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* mm: slub: Fix slab walking for init_on_freeLaura Abbott2019-07-311-2/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | To properly clear the slab on free with slab_want_init_on_free, we walk the list of free objects using get_freepointer/set_freepointer. The value we get from get_freepointer may not be valid. This isn't an issue since an actual value will get written later but this means there's a chance of triggering a bug if we use this value with set_freepointer: kernel BUG at mm/slub.c:306! invalid opcode: 0000 [#1] PREEMPT PTI CPU: 0 PID: 0 Comm: swapper Not tainted 5.2.0-05754-g6471384a #4 RIP: 0010:kfree+0x58a/0x5c0 Code: 48 83 05 78 37 51 02 01 0f 0b 48 83 05 7e 37 51 02 01 48 83 05 7e 37 51 02 01 48 83 05 7e 37 51 02 01 48 83 05 d6 37 51 02 01 <0f> 0b 48 83 05 d4 37 51 02 01 48 83 05 d4 37 51 02 01 48 83 05 d4 RSP: 0000:ffffffff82603d90 EFLAGS: 00010002 RAX: ffff8c3976c04320 RBX: ffff8c3976c04300 RCX: 0000000000000000 RDX: ffff8c3976c04300 RSI: 0000000000000000 RDI: ffff8c3976c04320 RBP: ffffffff82603db8 R08: 0000000000000000 R09: 0000000000000000 R10: ffff8c3976c04320 R11: ffffffff8289e1e0 R12: ffffd52cc8db0100 R13: ffff8c3976c01a00 R14: ffffffff810f10d4 R15: ffff8c3976c04300 FS: 0000000000000000(0000) GS:ffffffff8266b000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffff8c397ffff000 CR3: 0000000125020000 CR4: 00000000000406b0 Call Trace: apply_wqattrs_prepare+0x154/0x280 apply_workqueue_attrs_locked+0x4e/0xe0 apply_workqueue_attrs+0x36/0x60 alloc_workqueue+0x25a/0x6d0 workqueue_init_early+0x246/0x348 start_kernel+0x3c7/0x7ec x86_64_start_reservations+0x40/0x49 x86_64_start_kernel+0xda/0xe4 secondary_startup_64+0xb6/0xc0 Modules linked in: ---[ end trace f67eb9af4d8d492b ]--- Fix this by ensuring the value we set with set_freepointer is either NULL or another value in the chain. Reported-by: kernel test robot <rong.a.chen@intel.com> Signed-off-by: Laura Abbott <labbott@redhat.com> Fixes: 6471384af2a6 ("mm: security: introduce init_on_alloc=1 and init_on_free=1 boot options") Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: security: introduce init_on_alloc=1 and init_on_free=1 boot optionsAlexander Potapenko2019-07-121-5/+35
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Patch series "add init_on_alloc/init_on_free boot options", v10. Provide init_on_alloc and init_on_free boot options. These are aimed at preventing possible information leaks and making the control-flow bugs that depend on uninitialized values more deterministic. Enabling either of the options guarantees that the memory returned by the page allocator and SL[AU]B is initialized with zeroes. SLOB allocator isn't supported at the moment, as its emulation of kmem caches complicates handling of SLAB_TYPESAFE_BY_RCU caches correctly. Enabling init_on_free also guarantees that pages and heap objects are initialized right after they're freed, so it won't be possible to access stale data by using a dangling pointer. As suggested by Michal Hocko, right now we don't let the heap users to disable initialization for certain allocations. There's not enough evidence that doing so can speed up real-life cases, and introducing ways to opt-out may result in things going out of control. This patch (of 2): The new options are needed to prevent possible information leaks and make control-flow bugs that depend on uninitialized values more deterministic. This is expected to be on-by-default on Android and Chrome OS. And it gives the opportunity for anyone else to use it under distros too via the boot args. (The init_on_free feature is regularly requested by folks where memory forensics is included in their threat models.) init_on_alloc=1 makes the kernel initialize newly allocated pages and heap objects with zeroes. Initialization is done at allocation time at the places where checks for __GFP_ZERO are performed. init_on_free=1 makes the kernel initialize freed pages and heap objects with zeroes upon their deletion. This helps to ensure sensitive data doesn't leak via use-after-free accesses. Both init_on_alloc=1 and init_on_free=1 guarantee that the allocator returns zeroed memory. The two exceptions are slab caches with constructors and SLAB_TYPESAFE_BY_RCU flag. Those are never zero-initialized to preserve their semantics. Both init_on_alloc and init_on_free default to zero, but those defaults can be overridden with CONFIG_INIT_ON_ALLOC_DEFAULT_ON and CONFIG_INIT_ON_FREE_DEFAULT_ON. If either SLUB poisoning or page poisoning is enabled, those options take precedence over init_on_alloc and init_on_free: initialization is only applied to unpoisoned allocations. Slowdown for the new features compared to init_on_free=0, init_on_alloc=0: hackbench, init_on_free=1: +7.62% sys time (st.err 0.74%) hackbench, init_on_alloc=1: +7.75% sys time (st.err 2.14%) Linux build with -j12, init_on_free=1: +8.38% wall time (st.err 0.39%) Linux build with -j12, init_on_free=1: +24.42% sys time (st.err 0.52%) Linux build with -j12, init_on_alloc=1: -0.13% wall time (st.err 0.42%) Linux build with -j12, init_on_alloc=1: +0.57% sys time (st.err 0.40%) The slowdown for init_on_free=0, init_on_alloc=0 compared to the baseline is within the standard error. The new features are also going to pave the way for hardware memory tagging (e.g. arm64's MTE), which will require both on_alloc and on_free hooks to set the tags for heap objects. With MTE, tagging will have the same cost as memory initialization. Although init_on_free is rather costly, there are paranoid use-cases where in-memory data lifetime is desired to be minimized. There are various arguments for/against the realism of the associated threat models, but given that we'll need the infrastructure for MTE anyway, and there are people who want wipe-on-free behavior no matter what the performance cost, it seems reasonable to include it in this series. [glider@google.com: v8] Link: http://lkml.kernel.org/r/20190626121943.131390-2-glider@google.com [glider@google.com: v9] Link: http://lkml.kernel.org/r/20190627130316.254309-2-glider@google.com [glider@google.com: v10] Link: http://lkml.kernel.org/r/20190628093131.199499-2-glider@google.com Link: http://lkml.kernel.org/r/20190617151050.92663-2-glider@google.com Signed-off-by: Alexander Potapenko <glider@google.com> Acked-by: Kees Cook <keescook@chromium.org> Acked-by: Michal Hocko <mhocko@suse.cz> [page and dmapool parts Acked-by: James Morris <jamorris@linux.microsoft.com>] Cc: Christoph Lameter <cl@linux.com> Cc: Masahiro Yamada <yamada.masahiro@socionext.com> Cc: "Serge E. Hallyn" <serge@hallyn.com> Cc: Nick Desaulniers <ndesaulniers@google.com> Cc: Kostya Serebryany <kcc@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Sandeep Patil <sspatil@android.com> Cc: Laura Abbott <labbott@redhat.com> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Jann Horn <jannh@google.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Marco Elver <elver@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: memcg/slab: unify SLAB and SLUB page accountingRoman Gushchin2019-07-121-12/+2
| | | | | | | | | | | | | | | | | | | | | | | | Currently the page accounting code is duplicated in SLAB and SLUB internals. Let's move it into new (un)charge_slab_page helpers in the slab_common.c file. These helpers will be responsible for statistics (global and memcg-aware) and memcg charging. So they are replacing direct memcg_(un)charge_slab() calls. Link: http://lkml.kernel.org/r/20190611231813.3148843-6-guro@fb.com Signed-off-by: Roman Gushchin <guro@fb.com> Reviewed-by: Shakeel Butt <shakeelb@google.com> Acked-by: Christoph Lameter <cl@linux.com> Acked-by: Vladimir Davydov <vdavydov.dev@gmail.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Waiman Long <longman@redhat.com> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Andrei Vagin <avagin@gmail.com> Cc: Qian Cai <cai@lca.pw> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: memcg/slab: generalize postponed non-root kmem_cache deactivationRoman Gushchin2019-07-121-7/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently SLUB uses a work scheduled after an RCU grace period to deactivate a non-root kmem_cache. This mechanism can be reused for kmem_caches release, but requires generalization for SLAB case. Introduce kmemcg_cache_deactivate() function, which calls allocator-specific __kmem_cache_deactivate() and schedules execution of __kmem_cache_deactivate_after_rcu() with all necessary locks in a worker context after an rcu grace period. Here is the new calling scheme: kmemcg_cache_deactivate() __kmemcg_cache_deactivate() SLAB/SLUB-specific kmemcg_rcufn() rcu kmemcg_workfn() work __kmemcg_cache_deactivate_after_rcu() SLAB/SLUB-specific instead of: __kmemcg_cache_deactivate() SLAB/SLUB-specific slab_deactivate_memcg_cache_rcu_sched() SLUB-only kmemcg_rcufn() rcu kmemcg_workfn() work kmemcg_cache_deact_after_rcu() SLUB-only For consistency, all allocator-specific functions start with "__". Link: http://lkml.kernel.org/r/20190611231813.3148843-4-guro@fb.com Signed-off-by: Roman Gushchin <guro@fb.com> Acked-by: Vladimir Davydov <vdavydov.dev@gmail.com> Reviewed-by: Shakeel Butt <shakeelb@google.com> Cc: Christoph Lameter <cl@linux.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Waiman Long <longman@redhat.com> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Andrei Vagin <avagin@gmail.com> Cc: Qian Cai <cai@lca.pw> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: memcg/slab: postpone kmem_cache memcg pointer initialization to ↵Roman Gushchin2019-07-121-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | memcg_link_cache() Patch series "mm: reparent slab memory on cgroup removal", v7. # Why do we need this? We've noticed that the number of dying cgroups is steadily growing on most of our hosts in production. The following investigation revealed an issue in the userspace memory reclaim code [1], accounting of kernel stacks [2], and also the main reason: slab objects. The underlying problem is quite simple: any page charged to a cgroup holds a reference to it, so the cgroup can't be reclaimed unless all charged pages are gone. If a slab object is actively used by other cgroups, it won't be reclaimed, and will prevent the origin cgroup from being reclaimed. Slab objects, and first of all vfs cache, is shared between cgroups, which are using the same underlying fs, and what's even more important, it's shared between multiple generations of the same workload. So if something is running periodically every time in a new cgroup (like how systemd works), we do accumulate multiple dying cgroups. Strictly speaking pagecache isn't different here, but there is a key difference: we disable protection and apply some extra pressure on LRUs of dying cgroups, and these LRUs contain all charged pages. My experiments show that with the disabled kernel memory accounting the number of dying cgroups stabilizes at a relatively small number (~100, depends on memory pressure and cgroup creation rate), and with kernel memory accounting it grows pretty steadily up to several thousands. Memory cgroups are quite complex and big objects (mostly due to percpu stats), so it leads to noticeable memory losses. Memory occupied by dying cgroups is measured in hundreds of megabytes. I've even seen a host with more than 100Gb of memory wasted for dying cgroups. It leads to a degradation of performance with the uptime, and generally limits the usage of cgroups. My previous attempt [3] to fix the problem by applying extra pressure on slab shrinker lists caused a regressions with xfs and ext4, and has been reverted [4]. The following attempts to find the right balance [5, 6] were not successful. So instead of trying to find a maybe non-existing balance, let's do reparent accounted slab caches to the parent cgroup on cgroup removal. # Implementation approach There is however a significant problem with reparenting of slab memory: there is no list of charged pages. Some of them are in shrinker lists, but not all. Introducing of a new list is really not an option. But fortunately there is a way forward: every slab page has a stable pointer to the corresponding kmem_cache. So the idea is to reparent kmem_caches instead of slab pages. It's actually simpler and cheaper, but requires some underlying changes: 1) Make kmem_caches to hold a single reference to the memory cgroup, instead of a separate reference per every slab page. 2) Stop setting page->mem_cgroup pointer for memcg slab pages and use page->kmem_cache->memcg indirection instead. It's used only on slab page release, so performance overhead shouldn't be a big issue. 3) Introduce a refcounter for non-root slab caches. It's required to be able to destroy kmem_caches when they become empty and release the associated memory cgroup. There is a bonus: currently we release all memcg kmem_caches all together with the memory cgroup itself. This patchset allows individual kmem_caches to be released as soon as they become inactive and free. Some additional implementation details are provided in corresponding commit messages. # Results Below is the average number of dying cgroups on two groups of our production hosts. They do run some sort of web frontend workload, the memory pressure is moderate. As we can see, with the kernel memory reparenting the number stabilizes in 60s range; however with the original version it grows almost linearly and doesn't show any signs of plateauing. The difference in slab and percpu usage between patched and unpatched versions also grows linearly. In 7 days it exceeded 200Mb. day 0 1 2 3 4 5 6 7 original 56 362 628 752 1070 1250 1490 1560 patched 23 46 51 55 60 57 67 69 mem diff(Mb) 22 74 123 152 164 182 214 241 # Links [1]: commit 68600f623d69 ("mm: don't miss the last page because of round-off error") [2]: commit 9b6f7e163cd0 ("mm: rework memcg kernel stack accounting") [3]: commit 172b06c32b94 ("mm: slowly shrink slabs with a relatively small number of objects") [4]: commit a9a238e83fbb ("Revert "mm: slowly shrink slabs with a relatively small number of objects") [5]: https://lkml.org/lkml/2019/1/28/1865 [6]: https://marc.info/?l=linux-mm&m=155064763626437&w=2 This patch (of 10): Initialize kmem_cache->memcg_params.memcg pointer in memcg_link_cache() rather than in init_memcg_params(). Once kmem_cache will hold a reference to the memory cgroup, it will simplify the refcounting. For non-root kmem_caches memcg_link_cache() is always called before the kmem_cache becomes visible to a user, so it's safe. Link: http://lkml.kernel.org/r/20190611231813.3148843-2-guro@fb.com Signed-off-by: Roman Gushchin <guro@fb.com> Reviewed-by: Shakeel Butt <shakeelb@google.com> Acked-by: Vladimir Davydov <vdavydov.dev@gmail.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Waiman Long <longman@redhat.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Andrei Vagin <avagin@gmail.com> Cc: Qian Cai <cai@lca.pw> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/slab: refactor common ksize KASAN logic into slab_common.cMarco Elver2019-07-121-12/+2
| | | | | | | | | | | | | | | | | | | | | This refactors common code of ksize() between the various allocators into slab_common.c: __ksize() is the allocator-specific implementation without instrumentation, whereas ksize() includes the required KASAN logic. Link: http://lkml.kernel.org/r/20190626142014.141844-5-elver@google.com Signed-off-by: Marco Elver <elver@google.com> Acked-by: Christoph Lameter <cl@linux.com> Reviewed-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Alexander Potapenko <glider@google.com> Cc: Andrey Konovalov <andreyknvl@google.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Kees Cook <keescook@chromium.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* slub: don't panic for memcg kmem cache creation failureShakeel Butt2019-07-121-4/+0
| | | | | | | | | | | | | | | | | | | | | | | | | Currently for CONFIG_SLUB, if a memcg kmem cache creation is failed and the corresponding root kmem cache has SLAB_PANIC flag, the kernel will be crashed. This is unnecessary as the kernel can handle the creation failures of memcg kmem caches. Additionally CONFIG_SLAB does not implement this behavior. So, to keep the behavior consistent between SLAB and SLUB, removing the panic for memcg kmem cache creation failures. The root kmem cache creation failure for SLAB_PANIC correctly panics for both SLAB and SLUB. Link: http://lkml.kernel.org/r/20190619232514.58994-1-shakeelb@google.com Reported-by: Dave Hansen <dave.hansen@intel.com> Signed-off-by: Shakeel Butt <shakeelb@google.com> Acked-by: David Rientjes <rientjes@google.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Christoph Lameter <cl@linux.com> Cc: Roman Gushchin <guro@fb.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/slub.c: avoid double string traverse in kmem_cache_flags()Yury Norov2019-07-121-3/+1
| | | | | | | | | | | | | | | | If ',' is not found, kmem_cache_flags() calls strlen() to find the end of line. We can do it in a single pass using strchrnul(). Link: http://lkml.kernel.org/r/20190501053111.7950-1-ynorov@marvell.com Signed-off-by: Yury Norov <ynorov@marvell.com> Acked-by: Aaron Tomlin <atomlin@redhat.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/slub.c: update the comment about slab frozenLiu Xiang2019-05-141-4/+5
| | | | | | | | | | | | | Now frozen slab can only be on the per cpu partial list. Link: http://lkml.kernel.org/r/1554022325-11305-1-git-send-email-liu.xiang6@zte.com.cn Signed-off-by: Liu Xiang <liu.xiang6@zte.com.cn> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* slub: remove useless kmem_cache_debug() before remove_full()Liu Xiang2019-05-141-2/+1
| | | | | | | | | | | | | | | | When CONFIG_SLUB_DEBUG is not enabled, remove_full() is empty. While CONFIG_SLUB_DEBUG is enabled, remove_full() can check s->flags by itself. So kmem_cache_debug() is useless and can be removed. Link: http://lkml.kernel.org/r/1552577313-2830-1-git-send-email-liu.xiang6@zte.com.cn Signed-off-by: Liu Xiang <liu.xiang6@zte.com.cn> Acked-by: David Rientjes <rientjes@google.com> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* slub: use slab_list instead of lruTobin C. Harding2019-05-141-20/+20
| | | | | | | | | | | | | | | | | | | | | Currently we use the page->lru list for maintaining lists of slabs. We have a list in the page structure (slab_list) that can be used for this purpose. Doing so makes the code cleaner since we are not overloading the lru list. Use the slab_list instead of the lru list for maintaining lists of slabs. Link: http://lkml.kernel.org/r/20190402230545.2929-6-tobin@kernel.org Signed-off-by: Tobin C. Harding <tobin@kernel.org> Acked-by: Christoph Lameter <cl@linux.com> Reviewed-by: Roman Gushchin <guro@fb.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Pekka Enberg <penberg@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* slub: add comments to endif pre-processor macrosTobin C. Harding2019-05-141-10/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | SLUB allocator makes heavy use of ifdef/endif pre-processor macros. The pairing of these statements is at times hard to follow e.g. if the pair are further than a screen apart or if there are nested pairs. We can reduce cognitive load by adding a comment to the endif statement of form #ifdef CONFIG_FOO ... #endif /* CONFIG_FOO */ Add comments to endif pre-processor macros if ifdef/endif pair is not immediately apparent. Link: http://lkml.kernel.org/r/20190402230545.2929-5-tobin@kernel.org Signed-off-by: Tobin C. Harding <tobin@kernel.org> Acked-by: Christoph Lameter <cl@linux.com> Reviewed-by: Roman Gushchin <guro@fb.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Pekka Enberg <penberg@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/slub: Simplify stack trace retrievalThomas Gleixner2019-04-291-8/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Replace the indirection through struct stack_trace with an invocation of the storage array based interface. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com> Acked-by: Christoph Lameter <cl@linux.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Pekka Enberg <penberg@kernel.org> Cc: linux-mm@kvack.org Cc: David Rientjes <rientjes@google.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Alexander Potapenko <glider@google.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: kasan-dev@googlegroups.com Cc: Mike Rapoport <rppt@linux.vnet.ibm.com> Cc: Akinobu Mita <akinobu.mita@gmail.com> Cc: Christoph Hellwig <hch@lst.de> Cc: iommu@lists.linux-foundation.org Cc: Robin Murphy <robin.murphy@arm.com> Cc: Marek Szyprowski <m.szyprowski@samsung.com> Cc: Johannes Thumshirn <jthumshirn@suse.de> Cc: David Sterba <dsterba@suse.com> Cc: Chris Mason <clm@fb.com> Cc: Josef Bacik <josef@toxicpanda.com> Cc: linux-btrfs@vger.kernel.org Cc: dm-devel@redhat.com Cc: Mike Snitzer <snitzer@redhat.com> Cc: Alasdair Kergon <agk@redhat.com> Cc: Daniel Vetter <daniel@ffwll.ch> Cc: intel-gfx@lists.freedesktop.org Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> Cc: dri-devel@lists.freedesktop.org Cc: David Airlie <airlied@linux.ie> Cc: Jani Nikula <jani.nikula@linux.intel.com> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com> Cc: Tom Zanussi <tom.zanussi@linux.intel.com> Cc: Miroslav Benes <mbenes@suse.cz> Cc: linux-arch@vger.kernel.org Link: https://lkml.kernel.org/r/20190425094801.771410441@linutronix.de
* mm/slub: Remove the ULONG_MAX stack trace hackeryThomas Gleixner2019-04-141-9/+4
| | | | | | | | | | | | | | | | | | | | | | | No architecture terminates the stack trace with ULONG_MAX anymore. Remove the cruft. While at it remove the pointless loop of clearing the stack array completely. It's sufficient to clear the last entry as the consumers break out on the first zeroed entry anyway. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Alexander Potapenko <glider@google.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Pekka Enberg <penberg@kernel.org> Cc: linux-mm@kvack.org Cc: David Rientjes <rientjes@google.com> Cc: Christoph Lameter <cl@linux.com> Link: https://lkml.kernel.org/r/20190410103644.574058244@linutronix.de
* mm: add support for kmem caches in DMA32 zoneNicolas Boichat2019-03-291-0/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Patch series "iommu/io-pgtable-arm-v7s: Use DMA32 zone for page tables", v6. This is a followup to the discussion in [1], [2]. IOMMUs using ARMv7 short-descriptor format require page tables (level 1 and 2) to be allocated within the first 4GB of RAM, even on 64-bit systems. For L1 tables that are bigger than a page, we can just use __get_free_pages with GFP_DMA32 (on arm64 systems only, arm would still use GFP_DMA). For L2 tables that only take 1KB, it would be a waste to allocate a full page, so we considered 3 approaches: 1. This series, adding support for GFP_DMA32 slab caches. 2. genalloc, which requires pre-allocating the maximum number of L2 page tables (4096, so 4MB of memory). 3. page_frag, which is not very memory-efficient as it is unable to reuse freed fragments until the whole page is freed. [3] This series is the most memory-efficient approach. stable@ note: We confirmed that this is a regression, and IOMMU errors happen on 4.19 and linux-next/master on MT8173 (elm, Acer Chromebook R13). The issue most likely starts from commit ad67f5a6545f ("arm64: replace ZONE_DMA with ZONE_DMA32"), i.e. 4.15, and presumably breaks a number of Mediatek platforms (and maybe others?). [1] https://lists.linuxfoundation.org/pipermail/iommu/2018-November/030876.html [2] https://lists.linuxfoundation.org/pipermail/iommu/2018-December/031696.html [3] https://patchwork.codeaurora.org/patch/671639/ This patch (of 3): IOMMUs using ARMv7 short-descriptor format require page tables to be allocated within the first 4GB of RAM, even on 64-bit systems. On arm64, this is done by passing GFP_DMA32 flag to memory allocation functions. For IOMMU L2 tables that only take 1KB, it would be a waste to allocate a full page using get_free_pages, so we considered 3 approaches: 1. This patch, adding support for GFP_DMA32 slab caches. 2. genalloc, which requires pre-allocating the maximum number of L2 page tables (4096, so 4MB of memory). 3. page_frag, which is not very memory-efficient as it is unable to reuse freed fragments until the whole page is freed. This change makes it possible to create a custom cache in DMA32 zone using kmem_cache_create, then allocate memory using kmem_cache_alloc. We do not create a DMA32 kmalloc cache array, as there are currently no users of kmalloc(..., GFP_DMA32). These calls will continue to trigger a warning, as we keep GFP_DMA32 in GFP_SLAB_BUG_MASK. This implies that calls to kmem_cache_*alloc on a SLAB_CACHE_DMA32 kmem_cache must _not_ use GFP_DMA32 (it is anyway redundant and unnecessary). Link: http://lkml.kernel.org/r/20181210011504.122604-2-drinkcat@chromium.org Signed-off-by: Nicolas Boichat <drinkcat@chromium.org> Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Will Deacon <will.deacon@arm.com> Cc: Robin Murphy <robin.murphy@arm.com> Cc: Joerg Roedel <joro@8bytes.org> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Sasha Levin <Alexander.Levin@microsoft.com> Cc: Huaisheng Ye <yehs1@lenovo.com> Cc: Mike Rapoport <rppt@linux.vnet.ibm.com> Cc: Yong Wu <yong.wu@mediatek.com> Cc: Matthias Brugger <matthias.bgg@gmail.com> Cc: Tomasz Figa <tfiga@google.com> Cc: Yingjoe Chen <yingjoe.chen@mediatek.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Matthew Wilcox <willy@infradead.org> Cc: Hsin-Yi Wang <hsinyi@chromium.org> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* numa: make "nr_node_ids" unsigned intAlexey Dobriyan2019-03-051-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Number of NUMA nodes can't be negative. This saves a few bytes on x86_64: add/remove: 0/0 grow/shrink: 4/21 up/down: 27/-265 (-238) Function old new delta hv_synic_alloc.cold 88 110 +22 prealloc_shrinker 260 262 +2 bootstrap 249 251 +2 sched_init_numa 1566 1567 +1 show_slab_objects 778 777 -1 s_show 1201 1200 -1 kmem_cache_init 346 345 -1 __alloc_workqueue_key 1146 1145 -1 mem_cgroup_css_alloc 1614 1612 -2 __do_sys_swapon 4702 4699 -3 __list_lru_init 655 651 -4 nic_probe 2379 2374 -5 store_user_store 118 111 -7 red_zone_store 106 99 -7 poison_store 106 99 -7 wq_numa_init 348 338 -10 __kmem_cache_empty 75 65 -10 task_numa_free 186 173 -13 merge_across_nodes_store 351 336 -15 irq_create_affinity_masks 1261 1246 -15 do_numa_crng_init 343 321 -22 task_numa_fault 4760 4737 -23 swapfile_init 179 156 -23 hv_synic_alloc 536 492 -44 apply_wqattrs_prepare 746 695 -51 Link: http://lkml.kernel.org/r/20190201223029.GA15820@avx2 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: fix some typos in mm directoryWei Yang2019-03-051-1/+1
| | | | | | | | | | | No functional change. Link: http://lkml.kernel.org/r/20190118235123.27843-1-richard.weiyang@gmail.com Signed-off-by: Wei Yang <richard.weiyang@gmail.com> Reviewed-by: Pekka Enberg <penberg@kernel.org> Acked-by: Mike Rapoport <rppt@linux.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm, slub: make the comment of put_cpu_partial() completeWei Yang2019-03-051-2/+2
| | | | | | | | | | | | | | | | | | There are two cases when put_cpu_partial() is invoked. * __slab_free * get_partial_node This patch just makes it cover these two cases. Link: http://lkml.kernel.org/r/20181025094437.18951-3-richard.weiyang@gmail.com Signed-off-by: Wei Yang <richard.weiyang@gmail.com> Acked-by: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/slub.c: remove an unused addr argumentQian Cai2019-03-051-3/+2
| | | | | | | | | | | | | | | | "addr" function argument is not used in alloc_consistency_checks() at all, so remove it. Link: http://lkml.kernel.org/r/20190211123214.35592-1-cai@lca.pw Fixes: becfda68abca ("slub: convert SLAB_DEBUG_FREE to SLAB_CONSISTENCY_CHECKS") Signed-off-by: Qian Cai <cai@lca.pw> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: David Rientjes <rientjes@google.com> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/slub.c: freelist is ensured to be NULL when new_slab() failsPeng Wang2019-03-051-2/+1
| | | | | | | | | | | | | | | | | | | new_slab_objects() will return immediately if freelist is not NULL. if (freelist) return freelist; One more assignment operation could be avoided. Link: http://lkml.kernel.org/r/20181229062512.30469-1-rocking@whu.edu.cn Signed-off-by: Peng Wang <rocking@whu.edu.cn> Reviewed-by: Pekka Enberg <penberg@kernel.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: David Rientjes <rientjes@google.com> Cc: Christoph Lameter <cl@linux.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* slub: fix a crash with SLUB_DEBUG + KASAN_SW_TAGSQian Cai2019-02-211-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In process_slab(), "p = get_freepointer()" could return a tagged pointer, but "addr = page_address()" always return a native pointer. As the result, slab_index() is messed up here, return (p - addr) / s->size; All other callers of slab_index() have the same situation where "addr" is from page_address(), so just need to untag "p". # cat /sys/kernel/slab/hugetlbfs_inode_cache/alloc_calls Unable to handle kernel paging request at virtual address 2bff808aa4856d48 Mem abort info: ESR = 0x96000007 Exception class = DABT (current EL), IL = 32 bits SET = 0, FnV = 0 EA = 0, S1PTW = 0 Data abort info: ISV = 0, ISS = 0x00000007 CM = 0, WnR = 0 swapper pgtable: 64k pages, 48-bit VAs, pgdp = 0000000002498338 [2bff808aa4856d48] pgd=00000097fcfd0003, pud=00000097fcfd0003, pmd=00000097fca30003, pte=00e8008b24850712 Internal error: Oops: 96000007 [#1] SMP CPU: 3 PID: 79210 Comm: read_all Tainted: G L 5.0.0-rc7+ #84 Hardware name: HPE Apollo 70 /C01_APACHE_MB , BIOS L50_5.13_1.0.6 07/10/2018 pstate: 00400089 (nzcv daIf +PAN -UAO) pc : get_map+0x78/0xec lr : get_map+0xa0/0xec sp : aeff808989e3f8e0 x29: aeff808989e3f940 x28: ffff800826200000 x27: ffff100012d47000 x26: 9700000000002500 x25: 0000000000000001 x24: 52ff8008200131f8 x23: 52ff8008200130a0 x22: 52ff800820013098 x21: ffff800826200000 x20: ffff100013172ba0 x19: 2bff808a8971bc00 x18: ffff1000148f5538 x17: 000000000000001b x16: 00000000000000ff x15: ffff1000148f5000 x14: 00000000000000d2 x13: 0000000000000001 x12: 0000000000000000 x11: 0000000020000002 x10: 2bff808aa4856d48 x9 : 0000020000000000 x8 : 68ff80082620ebb0 x7 : 0000000000000000 x6 : ffff1000105da1dc x5 : 0000000000000000 x4 : 0000000000000000 x3 : 0000000000000010 x2 : 2bff808a8971bc00 x1 : ffff7fe002098800 x0 : ffff80082620ceb0 Process read_all (pid: 79210, stack limit = 0x00000000f65b9361) Call trace: get_map+0x78/0xec process_slab+0x7c/0x47c list_locations+0xb0/0x3c8 alloc_calls_show+0x34/0x40 slab_attr_show+0x34/0x48 sysfs_kf_seq_show+0x2e4/0x570 kernfs_seq_show+0x12c/0x1a0 seq_read+0x48c/0xf84 kernfs_fop_read+0xd4/0x448 __vfs_read+0x94/0x5d4 vfs_read+0xcc/0x194 ksys_read+0x6c/0xe8 __arm64_sys_read+0x68/0xb0 el0_svc_handler+0x230/0x3bc el0_svc+0x8/0xc Code: d3467d2a 9ac92329 8b0a0e6a f9800151 (c85f7d4b) ---[ end trace a383a9a44ff13176 ]--- Kernel panic - not syncing: Fatal exception SMP: stopping secondary CPUs SMP: failed to stop secondary CPUs 1-7,32,40,127 Kernel Offset: disabled CPU features: 0x002,20000c18 Memory Limit: none ---[ end Kernel panic - not syncing: Fatal exception ]--- Link: http://lkml.kernel.org/r/20190220020251.82039-1-cai@lca.pw Signed-off-by: Qian Cai <cai@lca.pw> Reviewed-by: Andrey Konovalov <andreyknvl@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* slub: fix SLAB_CONSISTENCY_CHECKS + KASAN_SW_TAGSQian Cai2019-02-211-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Enabling SLUB_DEBUG's SLAB_CONSISTENCY_CHECKS with KASAN_SW_TAGS triggers endless false positives during boot below due to check_valid_pointer() checks tagged pointers which have no addresses that is valid within slab pages: BUG radix_tree_node (Tainted: G B ): Freelist Pointer check fails ----------------------------------------------------------------------------- INFO: Slab objects=69 used=69 fp=0x (null) flags=0x7ffffffc000200 INFO: Object @offset=15060037153926966016 fp=0x Redzone: bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb ................ Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ Object : 00 00 00 00 00 00 00 00 18 6b 06 00 08 80 ff d0 .........k...... Object : 18 6b 06 00 08 80 ff d0 00 00 00 00 00 00 00 00 .k.............. Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ Redzone: bb bb bb bb bb bb bb bb ........ Padding: 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a ZZZZZZZZZZZZZZZZ CPU: 0 PID: 0 Comm: swapper/0 Tainted: G B 5.0.0-rc5+ #18 Call trace: dump_backtrace+0x0/0x450 show_stack+0x20/0x2c __dump_stack+0x20/0x28 dump_stack+0xa0/0xfc print_trailer+0x1bc/0x1d0 object_err+0x40/0x50 alloc_debug_processing+0xf0/0x19c ___slab_alloc+0x554/0x704 kmem_cache_alloc+0x2f8/0x440 radix_tree_node_alloc+0x90/0x2fc idr_get_free+0x1e8/0x6d0 idr_alloc_u32+0x11c/0x2a4 idr_alloc+0x74/0xe0 worker_pool_assign_id+0x5c/0xbc workqueue_init_early+0x49c/0xd50 start_kernel+0x52c/0xac4 FIX radix_tree_node: Marking all objects used Link: http://lkml.kernel.org/r/20190209044128.3290-1-cai@lca.pw Signed-off-by: Qian Cai <cai@lca.pw> Reviewed-by: Andrey Konovalov <andreyknvl@google.com> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* kasan, slub: fix more conflicts with CONFIG_SLAB_FREELIST_HARDENEDAndrey Konovalov2019-02-211-1/+12
| | | | | | | | | | | | | | | | | | | | | | | When CONFIG_KASAN_SW_TAGS is enabled, ptr_addr might be tagged. Normally, this doesn't cause any issues, as both set_freepointer() and get_freepointer() are called with a pointer with the same tag. However, there are some issues with CONFIG_SLUB_DEBUG code. For example, when __free_slub() iterates over objects in a cache, it passes untagged pointers to check_object(). check_object() in turns calls get_freepointer() with an untagged pointer, which causes the freepointer to be restored incorrectly. Add kasan_reset_tag to freelist_ptr(). Also add a detailed comment. Link: http://lkml.kernel.org/r/bf858f26ef32eb7bd24c665755b3aee4bc58d0e4.1550103861.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Reported-by: Qian Cai <cai@lca.pw> Tested-by: Qian Cai <cai@lca.pw> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Alexander Potapenko <glider@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* kasan, slub: fix conflicts with CONFIG_SLAB_FREELIST_HARDENEDAndrey Konovalov2019-02-211-13/+7
| | | | | | | | | | | | | | | | | | | | | | | | | CONFIG_SLAB_FREELIST_HARDENED hashes freelist pointer with the address of the object where the pointer gets stored. With tag based KASAN we don't account for that when building freelist, as we call set_freepointer() with the first argument untagged. This patch changes the code to properly propagate tags throughout the loop. Link: http://lkml.kernel.org/r/3df171559c52201376f246bf7ce3184fe21c1dc7.1549921721.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Reported-by: Qian Cai <cai@lca.pw> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Alexander Potapenko <glider@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Vincenzo Frascino <vincenzo.frascino@arm.com> Cc: Kostya Serebryany <kcc@google.com> Cc: Evgeniy Stepanov <eugenis@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* kasan, slub: move kasan_poison_slab hook before page_addressAndrey Konovalov2019-02-211-4/+15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | With tag based KASAN page_address() looks at the page flags to see whether the resulting pointer needs to have a tag set. Since we don't want to set a tag when page_address() is called on SLAB pages, we call page_kasan_tag_reset() in kasan_poison_slab(). However in allocate_slab() page_address() is called before kasan_poison_slab(). Fix it by changing the order. [andreyknvl@google.com: fix compilation error when CONFIG_SLUB_DEBUG=n] Link: http://lkml.kernel.org/r/ac27cc0bbaeb414ed77bcd6671a877cf3546d56e.1550066133.git.andreyknvl@google.com Link: http://lkml.kernel.org/r/cd895d627465a3f1c712647072d17f10883be2a1.1549921721.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Cc: Alexander Potapenko <glider@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Evgeniy Stepanov <eugenis@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Kostya Serebryany <kcc@google.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Qian Cai <cai@lca.pw> Cc: Vincenzo Frascino <vincenzo.frascino@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* kmemleak: account for tagged pointers when calculating pointer rangeAndrey Konovalov2019-02-211-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | kmemleak keeps two global variables, min_addr and max_addr, which store the range of valid (encountered by kmemleak) pointer values, which it later uses to speed up pointer lookup when scanning blocks. With tagged pointers this range will get bigger than it needs to be. This patch makes kmemleak untag pointers before saving them to min_addr and max_addr and when performing a lookup. Link: http://lkml.kernel.org/r/16e887d442986ab87fe87a755815ad92fa431a5f.1550066133.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Tested-by: Qian Cai <cai@lca.pw> Acked-by: Catalin Marinas <catalin.marinas@arm.com> Cc: Alexander Potapenko <glider@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Evgeniy Stepanov <eugenis@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Kostya Serebryany <kcc@google.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Vincenzo Frascino <vincenzo.frascino@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* kasan, kmemleak: pass tagged pointers to kmemleakAndrey Konovalov2019-02-211-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | Right now we call kmemleak hooks before assigning tags to pointers in KASAN hooks. As a result, when an objects gets allocated, kmemleak sees a differently tagged pointer, compared to the one it sees when the object gets freed. Fix it by calling KASAN hooks before kmemleak's ones. Link: http://lkml.kernel.org/r/cd825aa4897b0fc37d3316838993881daccbe9f5.1549921721.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Reported-by: Qian Cai <cai@lca.pw> Cc: Alexander Potapenko <glider@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Evgeniy Stepanov <eugenis@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Kostya Serebryany <kcc@google.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Vincenzo Frascino <vincenzo.frascino@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* kasan: make tag based mode work with CONFIG_HARDENED_USERCOPYAndrey Konovalov2019-01-081-0/+2
| | | | | | | | | | | | | | | | | | | | | With CONFIG_HARDENED_USERCOPY enabled __check_heap_object() compares and then subtracts a potentially tagged pointer with a non-tagged address of the page that this pointer belongs to, which leads to unexpected behavior. Untag the pointer in __check_heap_object() before doing any of these operations. Link: http://lkml.kernel.org/r/7e756a298d514c4482f52aea6151db34818d395d.1546540962.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Christoph Lameter <cl@linux.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Vincenzo Frascino <vincenzo.frascino@arm.com> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/slub.c: record final state of slub action in deactivate_slab()Wei Yang2018-12-281-14/+7
| | | | | | | | | | | | | | | | | | | If __cmpxchg_double_slab() fails and (l != m), current code records transition states of slub action. Update the action after __cmpxchg_double_slab() success to record the final state. [akpm@linux-foundation.org: more whitespace cleanup] Link: http://lkml.kernel.org/r/20181107013119.3816-1-richard.weiyang@gmail.com Signed-off-by: Wei Yang <richard.weiyang@gmail.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/slub.c: page is always non-NULL in node_match()Wei Yang2018-12-281-1/+1
| | | | | | | | | | | | | | | node_match() is a static function and is only invoked in slub.c. In all three places, `page' is ensured to be valid. Link: http://lkml.kernel.org/r/20181106150245.1668-1-richard.weiyang@gmail.com Signed-off-by: Wei Yang <richard.weiyang@gmail.com> Acked-by: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/slub.c: remove validation on cpu_slab in __flush_cpu_slab()Wei Yang2018-12-281-5/+3
| | | | | | | | | | | | | | | | | cpu_slab is a per cpu variable which is allocated in all or none. If a cpu_slab failed to be allocated, the slub is not usable. We could use cpu_slab without validation in __flush_cpu_slab(). Link: http://lkml.kernel.org/r/20181103141218.22844-1-richard.weiyang@gmail.com Signed-off-by: Wei Yang <richard.weiyang@gmail.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* kasan: preassign tags to objects with ctors or SLAB_TYPESAFE_BY_RCUAndrey Konovalov2018-12-281-10/+14
| | | | | | | | | | | | | | | | | | | | | | | | An object constructor can initialize pointers within this objects based on the address of the object. Since the object address might be tagged, we need to assign a tag before calling constructor. The implemented approach is to assign tags to objects with constructors when a slab is allocated and call constructors once as usual. The downside is that such object would always have the same tag when it is reallocated, so we won't catch use-after-frees on it. Also pressign tags for objects from SLAB_TYPESAFE_BY_RCU caches, since they can be validy accessed after having been freed. Link: http://lkml.kernel.org/r/f158a8a74a031d66f0a9398a5b0ed453c37ba09a.1544099024.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Reviewed-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Reviewed-by: Dmitry Vyukov <dvyukov@google.com> Cc: Christoph Lameter <cl@linux.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* kasan: add CONFIG_KASAN_GENERIC and CONFIG_KASAN_SW_TAGSAndrey Konovalov2018-12-281-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This commit splits the current CONFIG_KASAN config option into two: 1. CONFIG_KASAN_GENERIC, that enables the generic KASAN mode (the one that exists now); 2. CONFIG_KASAN_SW_TAGS, that enables the software tag-based KASAN mode. The name CONFIG_KASAN_SW_TAGS is chosen as in the future we will have another hardware tag-based KASAN mode, that will rely on hardware memory tagging support in arm64. With CONFIG_KASAN_SW_TAGS enabled, compiler options are changed to instrument kernel files with -fsantize=kernel-hwaddress (except the ones for which KASAN_SANITIZE := n is set). Both CONFIG_KASAN_GENERIC and CONFIG_KASAN_SW_TAGS support both CONFIG_KASAN_INLINE and CONFIG_KASAN_OUTLINE instrumentation modes. This commit also adds empty placeholder (for now) implementation of tag-based KASAN specific hooks inserted by the compiler and adjusts common hooks implementation. While this commit adds the CONFIG_KASAN_SW_TAGS config option, this option is not selectable, as it depends on HAVE_ARCH_KASAN_SW_TAGS, which we will enable once all the infrastracture code has been added. Link: http://lkml.kernel.org/r/b2550106eb8a68b10fefbabce820910b115aa853.1544099024.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Reviewed-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Reviewed-by: Dmitry Vyukov <dvyukov@google.com> Cc: Christoph Lameter <cl@linux.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* kasan, slub: handle pointer tags in early_kmem_cache_node_allocAndrey Konovalov2018-12-281-5/+5
| | | | | | | | | | | | | | | | | | The previous patch updated KASAN hooks signatures and their usage in SLAB and SLUB code, except for the early_kmem_cache_node_alloc function. This patch handles that function separately, as it requires to reorder some of the initialization code to correctly propagate a tagged pointer in case a tag is assigned by kasan_kmalloc. Link: http://lkml.kernel.org/r/fc8d0fdcf733a7a52e8d0daaa650f4736a57de8c.1544099024.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Christoph Lameter <cl@linux.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* kasan, mm: change hooks signaturesAndrey Konovalov2018-12-281-8/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Patch series "kasan: add software tag-based mode for arm64", v13. This patchset adds a new software tag-based mode to KASAN [1]. (Initially this mode was called KHWASAN, but it got renamed, see the naming rationale at the end of this section). The plan is to implement HWASan [2] for the kernel with the incentive, that it's going to have comparable to KASAN performance, but in the same time consume much less memory, trading that off for somewhat imprecise bug detection and being supported only for arm64. The underlying ideas of the approach used by software tag-based KASAN are: 1. By using the Top Byte Ignore (TBI) arm64 CPU feature, we can store pointer tags in the top byte of each kernel pointer. 2. Using shadow memory, we can store memory tags for each chunk of kernel memory. 3. On each memory allocation, we can generate a random tag, embed it into the returned pointer and set the memory tags that correspond to this chunk of memory to the same value. 4. By using compiler instrumentation, before each memory access we can add a check that the pointer tag matches the tag of the memory that is being accessed. 5. On a tag mismatch we report an error. With this patchset the existing KASAN mode gets renamed to generic KASAN, with the word "generic" meaning that the implementation can be supported by any architecture as it is purely software. The new mode this patchset adds is called software tag-based KASAN. The word "tag-based" refers to the fact that this mode uses tags embedded into the top byte of kernel pointers and the TBI arm64 CPU feature that allows to dereference such pointers. The word "software" here means that shadow memory manipulation and tag checking on pointer dereference is done in software. As it is the only tag-based implementation right now, "software tag-based" KASAN is sometimes referred to as simply "tag-based" in this patchset. A potential expansion of this mode is a hardware tag-based mode, which would use hardware memory tagging support (announced by Arm [3]) instead of compiler instrumentation and manual shadow memory manipulation. Same as generic KASAN, software tag-based KASAN is strictly a debugging feature. [1] https://www.kernel.org/doc/html/latest/dev-tools/kasan.html [2] http://clang.llvm.org/docs/HardwareAssistedAddressSanitizerDesign.html [3] https://community.arm.com/processors/b/blog/posts/arm-a-profile-architecture-2018-developments-armv85a ====== Rationale On mobile devices generic KASAN's memory usage is significant problem. One of the main reasons to have tag-based KASAN is to be able to perform a similar set of checks as the generic one does, but with lower memory requirements. Comment from Vishwath Mohan <vishwath@google.com>: I don't have data on-hand, but anecdotally both ASAN and KASAN have proven problematic to enable for environments that don't tolerate the increased memory pressure well. This includes (a) Low-memory form factors - Wear, TV, Things, lower-tier phones like Go, (c) Connected components like Pixel's visual core [1]. These are both places I'd love to have a low(er) memory footprint option at my disposal. Comment from Evgenii Stepanov <eugenis@google.com>: Looking at a live Android device under load, slab (according to /proc/meminfo) + kernel stack take 8-10% available RAM (~350MB). KASAN's overhead of 2x - 3x on top of it is not insignificant. Not having this overhead enables near-production use - ex. running KASAN/KHWASAN kernel on a personal, daily-use device to catch bugs that do not reproduce in test configuration. These are the ones that often cost the most engineering time to track down. CPU overhead is bad, but generally tolerable. RAM is critical, in our experience. Once it gets low enough, OOM-killer makes your life miserable. [1] https://www.blog.google/products/pixel/pixel-visual-core-image-processing-and-machine-learning-pixel-2/ ====== Technical details Software tag-based KASAN mode is implemented in a very similar way to the generic one. This patchset essentially does the following: 1. TCR_TBI1 is set to enable Top Byte Ignore. 2. Shadow memory is used (with a different scale, 1:16, so each shadow byte corresponds to 16 bytes of kernel memory) to store memory tags. 3. All slab objects are aligned to shadow scale, which is 16 bytes. 4. All pointers returned from the slab allocator are tagged with a random tag and the corresponding shadow memory is poisoned with the same value. 5. Compiler instrumentation is used to insert tag checks. Either by calling callbacks or by inlining them (CONFIG_KASAN_OUTLINE and CONFIG_KASAN_INLINE flags are reused). 6. When a tag mismatch is detected in callback instrumentation mode KASAN simply prints a bug report. In case of inline instrumentation, clang inserts a brk instruction, and KASAN has it's own brk handler, which reports the bug. 7. The memory in between slab objects is marked with a reserved tag, and acts as a redzone. 8. When a slab object is freed it's marked with a reserved tag. Bug detection is imprecise for two reasons: 1. We won't catch some small out-of-bounds accesses, that fall into the same shadow cell, as the last byte of a slab object. 2. We only have 1 byte to store tags, which means we have a 1/256 probability of a tag match for an incorrect access (actually even slightly less due to reserved tag values). Despite that there's a particular type of bugs that tag-based KASAN can detect compared to generic KASAN: use-after-free after the object has been allocated by someone else. ====== Testing Some kernel developers voiced a concern that changing the top byte of kernel pointers may lead to subtle bugs that are difficult to discover. To address this concern deliberate testing has been performed. It doesn't seem feasible to do some kind of static checking to find potential issues with pointer tagging, so a dynamic approach was taken. All pointer comparisons/subtractions have been instrumented in an LLVM compiler pass and a kernel module that would print a bug report whenever two pointers with different tags are being compared/subtracted (ignoring comparisons with NULL pointers and with pointers obtained by casting an error code to a pointer type) has been used. Then the kernel has been booted in QEMU and on an Odroid C2 board and syzkaller has been run. This yielded the following results. The two places that look interesting are: is_vmalloc_addr in include/linux/mm.h is_kernel_rodata in mm/util.c Here we compare a pointer with some fixed untagged values to make sure that the pointer lies in a particular part of the kernel address space. Since tag-based KASAN doesn't add tags to pointers that belong to rodata or vmalloc regions, this should work as is. To make sure debug checks to those two functions that check that the result doesn't change whether we operate on pointers with or without untagging has been added. A few other cases that don't look that interesting: Comparing pointers to achieve unique sorting order of pointee objects (e.g. sorting locks addresses before performing a double lock): tty_ldisc_lock_pair_timeout in drivers/tty/tty_ldisc.c pipe_double_lock in fs/pipe.c unix_state_double_lock in net/unix/af_unix.c lock_two_nondirectories in fs/inode.c mutex_lock_double in kernel/events/core.c ep_cmp_ffd in fs/eventpoll.c fsnotify_compare_groups fs/notify/mark.c Nothing needs to be done here, since the tags embedded into pointers don't change, so the sorting order would still be unique. Checks that a pointer belongs to some particular allocation: is_sibling_entry in lib/radix-tree.c object_is_on_stack in include/linux/sched/task_stack.h Nothing needs to be done here either, since two pointers can only belong to the same allocation if they have the same tag. Overall, since the kernel boots and works, there are no critical bugs. As for the rest, the traditional kernel testing way (use until fails) is the only one that looks feasible. Another point here is that tag-based KASAN is available under a separate config option that needs to be deliberately enabled. Even though it might be used in a "near-production" environment to find bugs that are not found during fuzzing or running tests, it is still a debug tool. ====== Benchmarks The following numbers were collected on Odroid C2 board. Both generic and tag-based KASAN were used in inline instrumentation mode. Boot time [1]: * ~1.7 sec for clean kernel * ~5.0 sec for generic KASAN * ~5.0 sec for tag-based KASAN Network performance [2]: * 8.33 Gbits/sec for clean kernel * 3.17 Gbits/sec for generic KASAN * 2.85 Gbits/sec for tag-based KASAN Slab memory usage after boot [3]: * ~40 kb for clean kernel * ~105 kb (~260% overhead) for generic KASAN * ~47 kb (~20% overhead) for tag-based KASAN KASAN memory overhead consists of three main parts: 1. Increased slab memory usage due to redzones. 2. Shadow memory (the whole reserved once during boot). 3. Quaratine (grows gradually until some preset limit; the more the limit, the more the chance to detect a use-after-free). Comparing tag-based vs generic KASAN for each of these points: 1. 20% vs 260% overhead. 2. 1/16th vs 1/8th of physical memory. 3. Tag-based KASAN doesn't require quarantine. [1] Time before the ext4 driver is initialized. [2] Measured as `iperf -s & iperf -c 127.0.0.1 -t 30`. [3] Measured as `cat /proc/meminfo | grep Slab`. ====== Some notes A few notes: 1. The patchset can be found here: https://github.com/xairy/kasan-prototype/tree/khwasan 2. Building requires a recent Clang version (7.0.0 or later). 3. Stack instrumentation is not supported yet and will be added later. This patch (of 25): Tag-based KASAN changes the value of the top byte of pointers returned from the kernel allocation functions (such as kmalloc). This patch updates KASAN hooks signatures and their usage in SLAB and SLUB code to reflect that. Link: http://lkml.kernel.org/r/aec2b5e3973781ff8a6bb6760f8543643202c451.1544099024.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Reviewed-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Reviewed-by: Dmitry Vyukov <dvyukov@google.com> Cc: Christoph Lameter <cl@linux.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm, slab: combine kmalloc_caches and kmalloc_dma_cachesVlastimil Babka2018-10-261-6/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Patch series "kmalloc-reclaimable caches", v4. As discussed at LSF/MM [1] here's a patchset that introduces kmalloc-reclaimable caches (more details in the second patch) and uses them for dcache external names. That allows us to repurpose the NR_INDIRECTLY_RECLAIMABLE_BYTES counter later in the series. With patch 3/6, dcache external names are allocated from kmalloc-rcl-* caches, eliminating the need for manual accounting. More importantly, it also ensures the reclaimable kmalloc allocations are grouped in pages separate from the regular kmalloc allocations. The need for proper accounting of dcache external names has shown it's easy for misbehaving process to allocate lots of them, causing premature OOMs. Without the added grouping, it's likely that a similar workload can interleave the dcache external names allocations with regular kmalloc allocations (note: I haven't searched myself for an example of such regular kmalloc allocation, but I would be very surprised if there wasn't some). A pathological case would be e.g. one 64byte regular allocations with 63 external dcache names in a page (64x64=4096), which means the page is not freed even after reclaiming after all dcache names, and the process can thus "steal" the whole page with single 64byte allocation. If other kmalloc users similar to dcache external names become identified, they can also benefit from the new functionality simply by adding __GFP_RECLAIMABLE to the kmalloc calls. Side benefits of the patchset (that could be also merged separately) include removed branch for detecting __GFP_DMA kmalloc(), and shortening kmalloc cache names in /proc/slabinfo output. The latter is potentially an ABI break in case there are tools parsing the names and expecting the values to be in bytes. This is how /proc/slabinfo looks like after booting in virtme: ... kmalloc-rcl-4M 0 0 4194304 1 1024 : tunables 1 1 0 : slabdata 0 0 0 ... kmalloc-rcl-96 7 32 128 32 1 : tunables 120 60 8 : slabdata 1 1 0 kmalloc-rcl-64 25 128 64 64 1 : tunables 120 60 8 : slabdata 2 2 0 kmalloc-rcl-32 0 0 32 124 1 : tunables 120 60 8 : slabdata 0 0 0 kmalloc-4M 0 0 4194304 1 1024 : tunables 1 1 0 : slabdata 0 0 0 kmalloc-2M 0 0 2097152 1 512 : tunables 1 1 0 : slabdata 0 0 0 kmalloc-1M 0 0 1048576 1 256 : tunables 1 1 0 : slabdata 0 0 0 ... /proc/vmstat with renamed nr_indirectly_reclaimable_bytes counter: ... nr_slab_reclaimable 2817 nr_slab_unreclaimable 1781 ... nr_kernel_misc_reclaimable 0 ... /proc/meminfo with new KReclaimable counter: ... Shmem: 564 kB KReclaimable: 11260 kB Slab: 18368 kB SReclaimable: 11260 kB SUnreclaim: 7108 kB KernelStack: 1248 kB ... This patch (of 6): The kmalloc caches currently mainain separate (optional) array kmalloc_dma_caches for __GFP_DMA allocations. There are tests for __GFP_DMA in the allocation hotpaths. We can avoid the branches by combining kmalloc_caches and kmalloc_dma_caches into a single two-dimensional array where the outer dimension is cache "type". This will also allow to add kmalloc-reclaimable caches as a third type. Link: http://lkml.kernel.org/r/20180731090649.16028-2-vbabka@suse.cz Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Christoph Lameter <cl@linux.com> Acked-by: Roman Gushchin <guro@fb.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Laura Abbott <labbott@redhat.com> Cc: Sumit Semwal <sumit.semwal@linaro.org> Cc: Vijayanand Jitta <vjitta@codeaurora.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* slub: extend slub debug to handle multiple slabsAaron Tomlin2018-10-261-6/+44
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Extend the slub_debug syntax to "slub_debug=<flags>[,<slub>]*", where <slub> may contain an asterisk at the end. For example, the following would poison all kmalloc slabs: slub_debug=P,kmalloc* and the following would apply the default flags to all kmalloc and all block IO slabs: slub_debug=,bio*,kmalloc* Please note that a similar patch was posted by Iliyan Malchev some time ago but was never merged: https://marc.info/?l=linux-mm&m=131283905330474&w=2 Link: http://lkml.kernel.org/r/20180928111139.27962-1-atomlin@redhat.com Signed-off-by: Aaron Tomlin <atomlin@redhat.com> Acked-by: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Iliyan Malchev <malchev@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/slub.c: switch to bitmap_zalloc()Andy Shevchenko2018-10-261-13/+7
| | | | | | | | | | | | | | | Switch to bitmap_zalloc() to show clearly what we are allocating. Besides that it returns pointer of bitmap type instead of opaque void *. Link: http://lkml.kernel.org/r/20180830104301.61649-1-andriy.shevchenko@linux.intel.com Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Acked-by: Christoph Lameter <cl@linux.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Tested-by: David Rientjes <rientjes@google.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* notifier: Remove notifier header file wherever not usedMukesh Ojha2018-08-301-1/+0
| | | | | | | | | | The conversion of the hotplug notifiers to a state machine left the notifier.h includes around in some places. Remove them. Signed-off-by: Mukesh Ojha <mojha@codeaurora.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/1535114033-4605-1-git-send-email-mojha@codeaurora.org
* mm, slub: restore the original intention of prefetch_freepointer()Vlastimil Babka2018-08-171-2/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | In SLUB, prefetch_freepointer() is used when allocating an object from cache's freelist, to make sure the next object in the list is cache-hot, since it's probable it will be allocated soon. Commit 2482ddec670f ("mm: add SLUB free list pointer obfuscation") has unintentionally changed the prefetch in a way where the prefetch is turned to a real fetch, and only the next->next pointer is prefetched. In case there is not a stream of allocations that would benefit from prefetching, the extra real fetch might add a useless cache miss to the allocation. Restore the previous behavior. Link: http://lkml.kernel.org/r/20180809085245.22448-1-vbabka@suse.cz Fixes: 2482ddec670f ("mm: add SLUB free list pointer obfuscation") Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Kees Cook <keescook@chromium.org> Cc: Daniel Micay <danielmicay@gmail.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* slub: fix failure when we delete and create a slab cacheMikulas Patocka2018-06-281-1/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In kernel 4.17 I removed some code from dm-bufio that did slab cache merging (commit 21bb13276768: "dm bufio: remove code that merges slab caches") - both slab and slub support merging caches with identical attributes, so dm-bufio now just calls kmem_cache_create and relies on implicit merging. This uncovered a bug in the slub subsystem - if we delete a cache and immediatelly create another cache with the same attributes, it fails because of duplicate filename in /sys/kernel/slab/. The slub subsystem offloads freeing the cache to a workqueue - and if we create the new cache before the workqueue runs, it complains because of duplicate filename in sysfs. This patch fixes the bug by moving the call of kobject_del from sysfs_slab_remove_workfn to shutdown_cache. kobject_del must be called while we hold slab_mutex - so that the sysfs entry is deleted before a cache with the same attributes could be created. Running device-mapper-test-suite with: dmtest run --suite thin-provisioning -n /commit_failure_causes_fallback/ triggered: Buffer I/O error on dev dm-0, logical block 1572848, async page read device-mapper: thin: 253:1: metadata operation 'dm_pool_alloc_data_block' failed: error = -5 device-mapper: thin: 253:1: aborting current metadata transaction sysfs: cannot create duplicate filename '/kernel/slab/:a-0000144' CPU: 2 PID: 1037 Comm: kworker/u48:1 Not tainted 4.17.0.snitm+ #25 Hardware name: Supermicro SYS-1029P-WTR/X11DDW-L, BIOS 2.0a 12/06/2017 Workqueue: dm-thin do_worker [dm_thin_pool] Call Trace: dump_stack+0x5a/0x73 sysfs_warn_dup+0x58/0x70 sysfs_create_dir_ns+0x77/0x80 kobject_add_internal+0xba/0x2e0 kobject_init_and_add+0x70/0xb0 sysfs_slab_add+0xb1/0x250 __kmem_cache_create+0x116/0x150 create_cache+0xd9/0x1f0 kmem_cache_create_usercopy+0x1c1/0x250 kmem_cache_create+0x18/0x20 dm_bufio_client_create+0x1ae/0x410 [dm_bufio] dm_block_manager_create+0x5e/0x90 [dm_persistent_data] __create_persistent_data_objects+0x38/0x940 [dm_thin_pool] dm_pool_abort_metadata+0x64/0x90 [dm_thin_pool] metadata_operation_failed+0x59/0x100 [dm_thin_pool] alloc_data_block.isra.53+0x86/0x180 [dm_thin_pool] process_cell+0x2a3/0x550 [dm_thin_pool] do_worker+0x28d/0x8f0 [dm_thin_pool] process_one_work+0x171/0x370 worker_thread+0x49/0x3f0 kthread+0xf8/0x130 ret_from_fork+0x35/0x40 kobject_add_internal failed for :a-0000144 with -EEXIST, don't try to register things with the same name in the same directory. kmem_cache_create(dm_bufio_buffer-16) failed with error -17 Link: http://lkml.kernel.org/r/alpine.LRH.2.02.1806151817130.6333@file01.intranet.prod.int.rdu2.redhat.com Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Reported-by: Mike Snitzer <snitzer@redhat.com> Tested-by: Mike Snitzer <snitzer@redhat.com> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* treewide: kzalloc() -> kcalloc()Kees Cook2018-06-121-3/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The kzalloc() function has a 2-factor argument form, kcalloc(). This patch replaces cases of: kzalloc(a * b, gfp) with: kcalloc(a * b, gfp) as well as handling cases of: kzalloc(a * b * c, gfp) with: kzalloc(array3_size(a, b, c), gfp) as it's slightly less ugly than: kzalloc_array(array_size(a, b), c, gfp) This does, however, attempt to ignore constant size factors like: kzalloc(4 * 1024, gfp) though any constants defined via macros get caught up in the conversion. Any factors with a sizeof() of "unsigned char", "char", and "u8" were dropped, since they're redundant. The Coccinelle script used for this was: // Fix redundant parens around sizeof(). @@ type TYPE; expression THING, E; @@ ( kzalloc( - (sizeof(TYPE)) * E + sizeof(TYPE) * E , ...) | kzalloc( - (sizeof(THING)) * E + sizeof(THING) * E , ...) ) // Drop single-byte sizes and redundant parens. @@ expression COUNT; typedef u8; typedef __u8; @@ ( kzalloc( - sizeof(u8) * (COUNT) + COUNT , ...) | kzalloc( - sizeof(__u8) * (COUNT) + COUNT , ...) | kzalloc( - sizeof(char) * (COUNT) + COUNT , ...) | kzalloc( - sizeof(unsigned char) * (COUNT) + COUNT , ...) | kzalloc( - sizeof(u8) * COUNT + COUNT , ...) | kzalloc( - sizeof(__u8) * COUNT + COUNT , ...) | kzalloc( - sizeof(char) * COUNT + COUNT , ...) | kzalloc( - sizeof(unsigned char) * COUNT + COUNT , ...) ) // 2-factor product with sizeof(type/expression) and identifier or constant. @@ type TYPE; expression THING; identifier COUNT_ID; constant COUNT_CONST; @@ ( - kzalloc + kcalloc ( - sizeof(TYPE) * (COUNT_ID) + COUNT_ID, sizeof(TYPE) , ...) | - kzalloc + kcalloc ( - sizeof(TYPE) * COUNT_ID + COUNT_ID, sizeof(TYPE) , ...) | - kzalloc + kcalloc ( - sizeof(TYPE) * (COUNT_CONST) + COUNT_CONST, sizeof(TYPE) , ...) | - kzalloc + kcalloc ( - sizeof(TYPE) * COUNT_CONST + COUNT_CONST, sizeof(TYPE) , ...) | - kzalloc + kcalloc ( - sizeof(THING) * (COUNT_ID) + COUNT_ID, sizeof(THING) , ...) | - kzalloc + kcalloc ( - sizeof(THING) * COUNT_ID + COUNT_ID, sizeof(THING) , ...) | - kzalloc + kcalloc ( - sizeof(THING) * (COUNT_CONST) + COUNT_CONST, sizeof(THING) , ...) | - kzalloc + kcalloc ( - sizeof(THING) * COUNT_CONST + COUNT_CONST, sizeof(THING) , ...) ) // 2-factor product, only identifiers. @@ identifier SIZE, COUNT; @@ - kzalloc + kcalloc ( - SIZE * COUNT + COUNT, SIZE , ...) // 3-factor product with 1 sizeof(type) or sizeof(expression), with // redundant parens removed. @@ expression THING; identifier STRIDE, COUNT; type TYPE; @@ ( kzalloc( - sizeof(TYPE) * (COUNT) * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | kzalloc( - sizeof(TYPE) * (COUNT) * STRIDE + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | kzalloc( - sizeof(TYPE) * COUNT * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | kzalloc( - sizeof(TYPE) * COUNT * STRIDE + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | kzalloc( - sizeof(THING) * (COUNT) * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) | kzalloc( - sizeof(THING) * (COUNT) * STRIDE + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) | kzalloc( - sizeof(THING) * COUNT * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) | kzalloc( - sizeof(THING) * COUNT * STRIDE + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) ) // 3-factor product with 2 sizeof(variable), with redundant parens removed. @@ expression THING1, THING2; identifier COUNT; type TYPE1, TYPE2; @@ ( kzalloc( - sizeof(TYPE1) * sizeof(TYPE2) * COUNT + array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2)) , ...) | kzalloc( - sizeof(TYPE1) * sizeof(THING2) * (COUNT) + array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2)) , ...) | kzalloc( - sizeof(THING1) * sizeof(THING2) * COUNT + array3_size(COUNT, sizeof(THING1), sizeof(THING2)) , ...) | kzalloc( - sizeof(THING1) * sizeof(THING2) * (COUNT) + array3_size(COUNT, sizeof(THING1), sizeof(THING2)) , ...) | kzalloc( - sizeof(TYPE1) * sizeof(THING2) * COUNT + array3_size(COUNT, sizeof(TYPE1), sizeof(THING2)) , ...) | kzalloc( - sizeof(TYPE1) * sizeof(THING2) * (COUNT) + array3_size(COUNT, sizeof(TYPE1), sizeof(THING2)) , ...) ) // 3-factor product, only identifiers, with redundant parens removed. @@ identifier STRIDE, SIZE, COUNT; @@ ( kzalloc( - (COUNT) * STRIDE * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) | kzalloc( - COUNT * (STRIDE) * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) | kzalloc( - COUNT * STRIDE * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | kzalloc( - (COUNT) * (STRIDE) * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) | kzalloc( - COUNT * (STRIDE) * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | kzalloc( - (COUNT) * STRIDE * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | kzalloc( - (COUNT) * (STRIDE) * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | kzalloc( - COUNT * STRIDE * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) ) // Any remaining multi-factor products, first at least 3-factor products, // when they're not all constants... @@ expression E1, E2, E3; constant C1, C2, C3; @@ ( kzalloc(C1 * C2 * C3, ...) | kzalloc( - (E1) * E2 * E3 + array3_size(E1, E2, E3) , ...) | kzalloc( - (E1) * (E2) * E3 + array3_size(E1, E2, E3) , ...) | kzalloc( - (E1) * (E2) * (E3) + array3_size(E1, E2, E3) , ...) | kzalloc( - E1 * E2 * E3 + array3_size(E1, E2, E3) , ...) ) // And then all remaining 2 factors products when they're not all constants, // keeping sizeof() as the second factor argument. @@ expression THING, E1, E2; type TYPE; constant C1, C2, C3; @@ ( kzalloc(sizeof(THING) * C2, ...) | kzalloc(sizeof(TYPE) * C2, ...) | kzalloc(C1 * C2 * C3, ...) | kzalloc(C1 * C2, ...) | - kzalloc + kcalloc ( - sizeof(TYPE) * (E2) + E2, sizeof(TYPE) , ...) | - kzalloc + kcalloc ( - sizeof(TYPE) * E2 + E2, sizeof(TYPE) , ...) | - kzalloc + kcalloc ( - sizeof(THING) * (E2) + E2, sizeof(THING) , ...) | - kzalloc + kcalloc ( - sizeof(THING) * E2 + E2, sizeof(THING) , ...) | - kzalloc + kcalloc ( - (E1) * E2 + E1, E2 , ...) | - kzalloc + kcalloc ( - (E1) * (E2) + E1, E2 , ...) | - kzalloc + kcalloc ( - E1 * E2 + E1, E2 , ...) ) Signed-off-by: Kees Cook <keescook@chromium.org>
* treewide: kmalloc() -> kmalloc_array()Kees Cook2018-06-121-5/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The kmalloc() function has a 2-factor argument form, kmalloc_array(). This patch replaces cases of: kmalloc(a * b, gfp) with: kmalloc_array(a * b, gfp) as well as handling cases of: kmalloc(a * b * c, gfp) with: kmalloc(array3_size(a, b, c), gfp) as it's slightly less ugly than: kmalloc_array(array_size(a, b), c, gfp) This does, however, attempt to ignore constant size factors like: kmalloc(4 * 1024, gfp) though any constants defined via macros get caught up in the conversion. Any factors with a sizeof() of "unsigned char", "char", and "u8" were dropped, since they're redundant. The tools/ directory was manually excluded, since it has its own implementation of kmalloc(). The Coccinelle script used for this was: // Fix redundant parens around sizeof(). @@ type TYPE; expression THING, E; @@ ( kmalloc( - (sizeof(TYPE)) * E + sizeof(TYPE) * E , ...) | kmalloc( - (sizeof(THING)) * E + sizeof(THING) * E , ...) ) // Drop single-byte sizes and redundant parens. @@ expression COUNT; typedef u8; typedef __u8; @@ ( kmalloc( - sizeof(u8) * (COUNT) + COUNT , ...) | kmalloc( - sizeof(__u8) * (COUNT) + COUNT , ...) | kmalloc( - sizeof(char) * (COUNT) + COUNT , ...) | kmalloc( - sizeof(unsigned char) * (COUNT) + COUNT , ...) | kmalloc( - sizeof(u8) * COUNT + COUNT , ...) | kmalloc( - sizeof(__u8) * COUNT + COUNT , ...) | kmalloc( - sizeof(char) * COUNT + COUNT , ...) | kmalloc( - sizeof(unsigned char) * COUNT + COUNT , ...) ) // 2-factor product with sizeof(type/expression) and identifier or constant. @@ type TYPE; expression THING; identifier COUNT_ID; constant COUNT_CONST; @@ ( - kmalloc + kmalloc_array ( - sizeof(TYPE) * (COUNT_ID) + COUNT_ID, sizeof(TYPE) , ...) | - kmalloc + kmalloc_array ( - sizeof(TYPE) * COUNT_ID + COUNT_ID, sizeof(TYPE) , ...) | - kmalloc + kmalloc_array ( - sizeof(TYPE) * (COUNT_CONST) + COUNT_CONST, sizeof(TYPE) , ...) | - kmalloc + kmalloc_array ( - sizeof(TYPE) * COUNT_CONST + COUNT_CONST, sizeof(TYPE) , ...) | - kmalloc + kmalloc_array ( - sizeof(THING) * (COUNT_ID) + COUNT_ID, sizeof(THING) , ...) | - kmalloc + kmalloc_array ( - sizeof(THING) * COUNT_ID + COUNT_ID, sizeof(THING) , ...) | - kmalloc + kmalloc_array ( - sizeof(THING) * (COUNT_CONST) + COUNT_CONST, sizeof(THING) , ...) | - kmalloc + kmalloc_array ( - sizeof(THING) * COUNT_CONST + COUNT_CONST, sizeof(THING) , ...) ) // 2-factor product, only identifiers. @@ identifier SIZE, COUNT; @@ - kmalloc + kmalloc_array ( - SIZE * COUNT + COUNT, SIZE , ...) // 3-factor product with 1 sizeof(type) or sizeof(expression), with // redundant parens removed. @@ expression THING; identifier STRIDE, COUNT; type TYPE; @@ ( kmalloc( - sizeof(TYPE) * (COUNT) * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | kmalloc( - sizeof(TYPE) * (COUNT) * STRIDE + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | kmalloc( - sizeof(TYPE) * COUNT * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | kmalloc( - sizeof(TYPE) * COUNT * STRIDE + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | kmalloc( - sizeof(THING) * (COUNT) * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) | kmalloc( - sizeof(THING) * (COUNT) * STRIDE + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) | kmalloc( - sizeof(THING) * COUNT * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) | kmalloc( - sizeof(THING) * COUNT * STRIDE + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) ) // 3-factor product with 2 sizeof(variable), with redundant parens removed. @@ expression THING1, THING2; identifier COUNT; type TYPE1, TYPE2; @@ ( kmalloc( - sizeof(TYPE1) * sizeof(TYPE2) * COUNT + array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2)) , ...) | kmalloc( - sizeof(TYPE1) * sizeof(THING2) * (COUNT) + array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2)) , ...) | kmalloc( - sizeof(THING1) * sizeof(THING2) * COUNT + array3_size(COUNT, sizeof(THING1), sizeof(THING2)) , ...) | kmalloc( - sizeof(THING1) * sizeof(THING2) * (COUNT) + array3_size(COUNT, sizeof(THING1), sizeof(THING2)) , ...) | kmalloc( - sizeof(TYPE1) * sizeof(THING2) * COUNT + array3_size(COUNT, sizeof(TYPE1), sizeof(THING2)) , ...) | kmalloc( - sizeof(TYPE1) * sizeof(THING2) * (COUNT) + array3_size(COUNT, sizeof(TYPE1), sizeof(THING2)) , ...) ) // 3-factor product, only identifiers, with redundant parens removed. @@ identifier STRIDE, SIZE, COUNT; @@ ( kmalloc( - (COUNT) * STRIDE * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) | kmalloc( - COUNT * (STRIDE) * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) | kmalloc( - COUNT * STRIDE * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | kmalloc( - (COUNT) * (STRIDE) * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) | kmalloc( - COUNT * (STRIDE) * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | kmalloc( - (COUNT) * STRIDE * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | kmalloc( - (COUNT) * (STRIDE) * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | kmalloc( - COUNT * STRIDE * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) ) // Any remaining multi-factor products, first at least 3-factor products, // when they're not all constants... @@ expression E1, E2, E3; constant C1, C2, C3; @@ ( kmalloc(C1 * C2 * C3, ...) | kmalloc( - (E1) * E2 * E3 + array3_size(E1, E2, E3) , ...) | kmalloc( - (E1) * (E2) * E3 + array3_size(E1, E2, E3) , ...) | kmalloc( - (E1) * (E2) * (E3) + array3_size(E1, E2, E3) , ...) | kmalloc( - E1 * E2 * E3 + array3_size(E1, E2, E3) , ...) ) // And then all remaining 2 factors products when they're not all constants, // keeping sizeof() as the second factor argument. @@ expression THING, E1, E2; type TYPE; constant C1, C2, C3; @@ ( kmalloc(sizeof(THING) * C2, ...) | kmalloc(sizeof(TYPE) * C2, ...) | kmalloc(C1 * C2 * C3, ...) | kmalloc(C1 * C2, ...) | - kmalloc + kmalloc_array ( - sizeof(TYPE) * (E2) + E2, sizeof(TYPE) , ...) | - kmalloc + kmalloc_array ( - sizeof(TYPE) * E2 + E2, sizeof(TYPE) , ...) | - kmalloc + kmalloc_array ( - sizeof(THING) * (E2) + E2, sizeof(THING) , ...) | - kmalloc + kmalloc_array ( - sizeof(THING) * E2 + E2, sizeof(THING) , ...) | - kmalloc + kmalloc_array ( - (E1) * E2 + E1, E2 , ...) | - kmalloc + kmalloc_array ( - (E1) * (E2) + E1, E2 , ...) | - kmalloc + kmalloc_array ( - E1 * E2 + E1, E2 , ...) ) Signed-off-by: Kees Cook <keescook@chromium.org>
* slub: remove 'reserved' file from sysfsMatthew Wilcox2018-06-071-7/+0
| | | | | | | | | | | | | | | | | | | | Christoph doubts anyone was using the 'reserved' file in sysfs, so remove it. Link: http://lkml.kernel.org/r/20180518194519.3820-17-willy@infradead.org Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com> Acked-by: Christoph Lameter <cl@linux.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Jérôme Glisse <jglisse@redhat.com> Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com> Cc: Lai Jiangshan <jiangshanlai@gmail.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* slub: remove kmem_cache->reservedMatthew Wilcox2018-06-071-21/+20
| | | | | | | | | | | | | | | | | | | | | The reserved field was only used for embedding an rcu_head in the data structure. With the previous commit, we no longer need it. That lets us remove the 'reserved' argument to a lot of functions. Link: http://lkml.kernel.org/r/20180518194519.3820-16-willy@infradead.org Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com> Acked-by: Christoph Lameter <cl@linux.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Jérôme Glisse <jglisse@redhat.com> Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com> Cc: Lai Jiangshan <jiangshanlai@gmail.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* slab,slub: remove rcu_head size checksMatthew Wilcox2018-06-071-25/+2
| | | | | | | | | | | | | | | | | | | | rcu_head may now grow larger than list_head without affecting slab or slub. Link: http://lkml.kernel.org/r/20180518194519.3820-15-willy@infradead.org Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com> Acked-by: Christoph Lameter <cl@linux.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Jérôme Glisse <jglisse@redhat.com> Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com> Cc: Lai Jiangshan <jiangshanlai@gmail.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: move lru union within struct pageMatthew Wilcox2018-06-071-4/+4
| | | | | | | | | | | | | | | | | | | | Since the LRU is two words, this does not affect the double-word alignment of SLUB's freelist. Link: http://lkml.kernel.org/r/20180518194519.3820-10-willy@infradead.org Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Christoph Lameter <cl@linux.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Jérôme Glisse <jglisse@redhat.com> Cc: Lai Jiangshan <jiangshanlai@gmail.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: move 'private' union within struct pageMatthew Wilcox2018-06-071-18/+2
| | | | | | | | | | | | | | | | | | | | | | | By moving page->private to the fourth word of struct page, we can put the SLUB counters in the same word as SLAB's s_mem and still do the cmpxchg_double trick. Now the SLUB counters no longer overlap with the mapcount or refcount so we can drop the call to page_mapcount_reset() and simplify set_page_slub_counters() to a single line. Link: http://lkml.kernel.org/r/20180518194519.3820-6-willy@infradead.org Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Christoph Lameter <cl@linux.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Jérôme Glisse <jglisse@redhat.com> Cc: Lai Jiangshan <jiangshanlai@gmail.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: switch s_mem and slab_cache in struct pageMatthew Wilcox2018-06-071-0/+1
| | | | | | | | | | | | | | | | | | | | | This will allow us to store slub's counters in the same bits as slab's s_mem. slub now needs to set page->mapping to NULL as it frees the page, just like slab does. Link: http://lkml.kernel.org/r/20180518194519.3820-5-willy@infradead.org Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com> Acked-by: Christoph Lameter <cl@linux.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Jérôme Glisse <jglisse@redhat.com> Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com> Cc: Lai Jiangshan <jiangshanlai@gmail.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/slub: remove obsolete commentCanjiang Lu2018-06-071-6/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The obsolete comment removed in this patch was introduced by 51df1142816e4 ("slub: Dynamically size kmalloc cache allocations"). I paste related modification from that commit: +#ifdef CONFIG_NUMA + /* + * Allocate kmem_cache_node properly from the kmem_cache slab. + * kmem_cache_node is separately allocated so no need to + * update any list pointers. + */ + temp_kmem_cache_node = kmem_cache_node; + kmem_cache_node = kmem_cache_alloc(kmem_cache, GFP_NOWAIT); + memcpy(kmem_cache_node, temp_kmem_cache_node, kmem_size); + + kmem_cache_bootstrap_fixup(kmem_cache_node); + + caches++; +#else + /* + * kmem_cache has kmem_cache_node embedded and we moved it! + * Update the list heads + */ + INIT_LIST_HEAD(&kmem_cache->local_node.partial); + list_splice(&temp_kmem_cache->local_node.partial, &kmem_cache->local_node.partial); +#ifdef CONFIG_SLUB_DEBUG + INIT_LIST_HEAD(&kmem_cache->local_node.full); + list_splice(&temp_kmem_cache->local_node.full, &kmem_cache->local_node.full); +#endif As we can see there're used to distinguish the difference handling between NUMA/non-NUMA configuration in the original commit. I think it doesn't make any sense in current implementation which is placed above kmem_cache_node = bootstrap(&boot_kmem_cache_node); So maybe it's better to remove them now? Link: http://lkml.kernel.org/r/5af26f58.1c69fb81.1be0e.c520SMTPIN_ADDED_BROKEN@mx.google.com Signed-off-by: Canjiang Lu <canjiang.lu@samsung.com> Acked-by: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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