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* mm, memory_hotplug: fix off-by-one in is_pageblock_removableMichal Hocko2019-02-211-12/+15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Rong Chen has reported the following boot crash: PGD 0 P4D 0 Oops: 0000 [#1] PREEMPT SMP PTI CPU: 1 PID: 239 Comm: udevd Not tainted 5.0.0-rc4-00149-gefad4e4 #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014 RIP: 0010:page_mapping+0x12/0x80 Code: 5d c3 48 89 df e8 0e ad 02 00 85 c0 75 da 89 e8 5b 5d c3 0f 1f 44 00 00 53 48 89 fb 48 8b 43 08 48 8d 50 ff a8 01 48 0f 45 da <48> 8b 53 08 48 8d 42 ff 83 e2 01 48 0f 44 c3 48 83 38 ff 74 2f 48 RSP: 0018:ffff88801fa87cd8 EFLAGS: 00010202 RAX: ffffffffffffffff RBX: fffffffffffffffe RCX: 000000000000000a RDX: fffffffffffffffe RSI: ffffffff820b9a20 RDI: ffff88801e5c0000 RBP: 6db6db6db6db6db7 R08: ffff88801e8bb000 R09: 0000000001b64d13 R10: ffff88801fa87cf8 R11: 0000000000000001 R12: ffff88801e640000 R13: ffffffff820b9a20 R14: ffff88801f145258 R15: 0000000000000001 FS: 00007fb2079817c0(0000) GS:ffff88801dd00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000006 CR3: 000000001fa82000 CR4: 00000000000006a0 Call Trace: __dump_page+0x14/0x2c0 is_mem_section_removable+0x24c/0x2c0 removable_show+0x87/0xa0 dev_attr_show+0x25/0x60 sysfs_kf_seq_show+0xba/0x110 seq_read+0x196/0x3f0 __vfs_read+0x34/0x180 vfs_read+0xa0/0x150 ksys_read+0x44/0xb0 do_syscall_64+0x5e/0x4a0 entry_SYSCALL_64_after_hwframe+0x49/0xbe and bisected it down to commit efad4e475c31 ("mm, memory_hotplug: is_mem_section_removable do not pass the end of a zone"). The reason for the crash is that the mapping is garbage for poisoned (uninitialized) page. This shouldn't happen as all pages in the zone's boundary should be initialized. Later debugging revealed that the actual problem is an off-by-one when evaluating the end_page. 'start_pfn + nr_pages' resp 'zone_end_pfn' refers to a pfn after the range and as such it might belong to a differen memory section. This along with CONFIG_SPARSEMEM then makes the loop condition completely bogus because a pointer arithmetic doesn't work for pages from two different sections in that memory model. Fix the issue by reworking is_pageblock_removable to be pfn based and only use struct page where necessary. This makes the code slightly easier to follow and we will remove the problematic pointer arithmetic completely. Link: http://lkml.kernel.org/r/20190218181544.14616-1-mhocko@kernel.org Fixes: efad4e475c31 ("mm, memory_hotplug: is_mem_section_removable do not pass the end of a zone") Signed-off-by: Michal Hocko <mhocko@suse.com> Reported-by: <rong.a.chen@intel.com> Tested-by: <rong.a.chen@intel.com> Acked-by: Mike Rapoport <rppt@linux.ibm.com> Reviewed-by: Oscar Salvador <osalvador@suse.de> Cc: Matthew Wilcox <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: don't let userspace spam allocations warningsDaniel Vetter2019-02-211-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | memdump_user usually gets fed unchecked userspace input. Blasting a full backtrace into dmesg every time is a bit excessive - I'm not sure on the kernel rule in general, but at least in drm we're trying not to let unpriviledge userspace spam the logs freely. Definitely not entire warning backtraces. It also means more filtering for our CI, because our testsuite exercises these corner cases and so hits these a lot. Link: http://lkml.kernel.org/r/20190220204058.11676-1-daniel.vetter@ffwll.ch Signed-off-by: Daniel Vetter <daniel.vetter@intel.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Michal Hocko <mhocko@suse.com> Reviewed-by: Kees Cook <keescook@chromium.org> Cc: Mike Rapoport <rppt@linux.vnet.ibm.com> Cc: Roman Gushchin <guro@fb.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Jan Stancek <jstancek@redhat.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Huang Ying <ying.huang@intel.com> Cc: Bartosz Golaszewski <brgl@bgdev.pl> 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>
* kasan, slab: remove redundant kasan_slab_alloc hooksAndrey Konovalov2019-02-211-2/+0
| | | | | | | | | | | | | | | | | | | kasan_slab_alloc() calls in kmem_cache_alloc() and kmem_cache_alloc_node() are redundant as they are already called via slab_alloc/slab_alloc_node()-> slab_post_alloc_hook()->kasan_slab_alloc(). Remove them. Link: http://lkml.kernel.org/r/4ca1655cdcfc4379c49c50f7bf80f81c4ad01485.1550602886.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Tested-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: Dmitry Vyukov <dvyukov@google.com> Cc: Evgeniy Stepanov <eugenis@google.com> Cc: Kostya Serebryany <kcc@google.com> 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, slab: make freelist stored without tagsAndrey Konovalov2019-02-211-2/+9
| | | | | | | | | | | | | | | | | | | | | Similarly to "kasan, slub: move kasan_poison_slab hook before page_address", move kasan_poison_slab() before alloc_slabmgmt(), which calls page_address(), to make page_address() return value to be non-tagged. This, combined with calling kasan_reset_tag() for off-slab slab management object, leads to freelist being stored non-tagged. Link: http://lkml.kernel.org/r/dfb53b44a4d00de3879a05a9f04c1f55e584f7a1.1550602886.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Tested-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: Dmitry Vyukov <dvyukov@google.com> Cc: Evgeniy Stepanov <eugenis@google.com> Cc: Kostya Serebryany <kcc@google.com> 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, slab: fix conflicts with CONFIG_HARDENED_USERCOPYAndrey Konovalov2019-02-211-0/+2
| | | | | | | | | | | | | | | | | | | Similarly to commit 96fedce27e13 ("kasan: make tag based mode work with CONFIG_HARDENED_USERCOPY"), we need to reset pointer tags in __check_heap_object() in mm/slab.c before doing any pointer math. Link: http://lkml.kernel.org/r/9a5c0f958db10e69df5ff9f2b997866b56b7effc.1550602886.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Tested-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: Dmitry Vyukov <dvyukov@google.com> Cc: Evgeniy Stepanov <eugenis@google.com> Cc: Kostya Serebryany <kcc@google.com> 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: prevent tracing of tags.cAndrey Konovalov2019-02-211-0/+2
| | | | | | | | | | | | | | | | | | | | Similarly to commit 0d0c8de8788b ("kasan: mark file common so ftrace doesn't trace it") add the -pg flag to mm/kasan/tags.c to prevent conflicts with tracing. Link: http://lkml.kernel.org/r/9c4c3ce5ccfb894c7fe66d91de7c1da2787b4da4.1550602886.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> Cc: Catalin Marinas <catalin.marinas@arm.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: fix random seed generation for tag-based modeAndrey Konovalov2019-02-211-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | There are two issues with assigning random percpu seeds right now: 1. We use for_each_possible_cpu() to iterate over cpus, but cpumask is not set up yet at the moment of kasan_init(), and thus we only set the seed for cpu #0. 2. A call to get_random_u32() always returns the same number and produces a message in dmesg, since the random subsystem is not yet initialized. Fix 1 by calling kasan_init_tags() after cpumask is set up. Fix 2 by using get_cycles() instead of get_random_u32(). This gives us lower quality random numbers, but it's good enough, as KASAN is meant to be used as a debugging tool and not a mitigation. Link: http://lkml.kernel.org/r/1f815cc914b61f3516ed4cc9bfd9eeca9bd5d9de.1550677973.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> 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>
* tmpfs: fix link accounting when a tmpfile is linked inDarrick J. Wong2019-02-211-3/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | tmpfs has a peculiarity of accounting hard links as if they were separate inodes: so that when the number of inodes is limited, as it is by default, a user cannot soak up an unlimited amount of unreclaimable dcache memory just by repeatedly linking a file. But when v3.11 added O_TMPFILE, and the ability to use linkat() on the fd, we missed accommodating this new case in tmpfs: "df -i" shows that an extra "inode" remains accounted after the file is unlinked and the fd closed and the actual inode evicted. If a user repeatedly links tmpfiles into a tmpfs, the limit will be hit (ENOSPC) even after they are deleted. Just skip the extra reservation from shmem_link() in this case: there's a sense in which this first link of a tmpfile is then cheaper than a hard link of another file, but the accounting works out, and there's still good limiting, so no need to do anything more complicated. Link: http://lkml.kernel.org/r/alpine.LSU.2.11.1902182134370.7035@eggly.anvils Fixes: f4e0c30c191 ("allow the temp files created by open() to be linked to") Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Hugh Dickins <hughd@google.com> Reported-by: Matej Kupljen <matej.kupljen@gmail.com> Acked-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: handle lru_add_drain_all for UP properlyMichal Hocko2019-02-211-7/+10
| | | | | | | | | | | | | | | | | | | | | | | | | Since for_each_cpu(cpu, mask) added by commit 2d3854a37e8b767a ("cpumask: introduce new API, without changing anything") did not evaluate the mask argument if NR_CPUS == 1 due to CONFIG_SMP=n, lru_add_drain_all() is hitting WARN_ON() at __flush_work() added by commit 4d43d395fed12463 ("workqueue: Try to catch flush_work() without INIT_WORK().") by unconditionally calling flush_work() [1]. Workaround this issue by using CONFIG_SMP=n specific lru_add_drain_all implementation. There is no real need to defer the implementation to the workqueue as the draining is going to happen on the local cpu. So alias lru_add_drain_all to lru_add_drain which does all the necessary work. [akpm@linux-foundation.org: fix various build warnings] [1] https://lkml.kernel.org/r/18a30387-6aa5-6123-e67c-57579ecc3f38@roeck-us.net Link: http://lkml.kernel.org/r/20190213124334.GH4525@dhcp22.suse.cz Signed-off-by: Michal Hocko <mhocko@suse.com> Reported-by: Guenter Roeck <linux@roeck-us.net> Debugged-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm, page_alloc: fix a division by zero error when boosting watermarks v2Mel Gorman2019-02-211-0/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | Yury Norov reported that an arm64 KVM instance could not boot since after v5.0-rc1 and could addressed by reverting the patches 1c30844d2dfe272d58c ("mm: reclaim small amounts of memory when an external 73444bc4d8f92e46a20 ("mm, page_alloc: do not wake kswapd with zone lock held") The problem is that a division by zero error is possible if boosting occurs very early in boot if the system has very little memory. This patch avoids the division by zero error. Link: http://lkml.kernel.org/r/20190213143012.GT9565@techsingularity.net Fixes: 1c30844d2dfe ("mm: reclaim small amounts of memory when an external fragmentation event occurs") Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Reported-by: Yury Norov <yury.norov@gmail.com> Tested-by: Yury Norov <yury.norov@gmail.com> Tested-by: Will Deacon <will.deacon@arm.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: David Rientjes <rientjes@google.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/debug.c: fix __dump_page() for poisoned pagesRobin Murphy2019-02-211-1/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Evaluating page_mapping() on a poisoned page ends up dereferencing junk and making PF_POISONED_CHECK() considerably crashier than intended: Unable to handle kernel NULL pointer dereference at virtual address 0000000000000006 Mem abort info: ESR = 0x96000005 Exception class = DABT (current EL), IL = 32 bits SET = 0, FnV = 0 EA = 0, S1PTW = 0 Data abort info: ISV = 0, ISS = 0x00000005 CM = 0, WnR = 0 user pgtable: 4k pages, 39-bit VAs, pgdp = 00000000c2f6ac38 [0000000000000006] pgd=0000000000000000, pud=0000000000000000 Internal error: Oops: 96000005 [#1] PREEMPT SMP Modules linked in: CPU: 2 PID: 491 Comm: bash Not tainted 5.0.0-rc1+ #1 Hardware name: ARM LTD ARM Juno Development Platform/ARM Juno Development Platform, BIOS EDK II Dec 17 2018 pstate: 00000005 (nzcv daif -PAN -UAO) pc : page_mapping+0x18/0x118 lr : __dump_page+0x1c/0x398 Process bash (pid: 491, stack limit = 0x000000004ebd4ecd) Call trace: page_mapping+0x18/0x118 __dump_page+0x1c/0x398 dump_page+0xc/0x18 remove_store+0xbc/0x120 dev_attr_store+0x18/0x28 sysfs_kf_write+0x40/0x50 kernfs_fop_write+0x130/0x1d8 __vfs_write+0x30/0x180 vfs_write+0xb4/0x1a0 ksys_write+0x60/0xd0 __arm64_sys_write+0x18/0x20 el0_svc_common+0x94/0xf8 el0_svc_handler+0x68/0x70 el0_svc+0x8/0xc Code: f9400401 d1000422 f240003f 9a801040 (f9400402) ---[ end trace cdb5eb5bf435cecb ]--- Fix that by not inspecting the mapping until we've determined that it's likely to be valid. Now the above condition still ends up stopping the kernel, but in the correct manner: page:ffffffbf20000000 is uninitialized and poisoned raw: ffffffffffffffff ffffffffffffffff ffffffffffffffff ffffffffffffffff raw: ffffffffffffffff ffffffffffffffff ffffffffffffffff ffffffffffffffff page dumped because: VM_BUG_ON_PAGE(PagePoisoned(p)) ------------[ cut here ]------------ kernel BUG at ./include/linux/mm.h:1006! Internal error: Oops - BUG: 0 [#1] PREEMPT SMP Modules linked in: CPU: 1 PID: 483 Comm: bash Not tainted 5.0.0-rc1+ #3 Hardware name: ARM LTD ARM Juno Development Platform/ARM Juno Development Platform, BIOS EDK II Dec 17 2018 pstate: 40000005 (nZcv daif -PAN -UAO) pc : remove_store+0xbc/0x120 lr : remove_store+0xbc/0x120 ... Link: http://lkml.kernel.org/r/03b53ee9d7e76cda4b9b5e1e31eea080db033396.1550071778.git.robin.murphy@arm.com Fixes: 1c6fb1d89e73 ("mm: print more information about mapping in __dump_page") Signed-off-by: Robin Murphy <robin.murphy@arm.com> Acked-by: Michal Hocko <mhocko@suse.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 Konovalov2019-02-214-3/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | 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 Konovalov2019-02-213-6/+5
| | | | | | | | | | | | | | | | | | | | | | | | 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: fix assigning tags twiceAndrey Konovalov2019-02-211-12/+17
| | | | | | | | | | | | | | | | | | | | | | | When an object is kmalloc()'ed, two hooks are called: kasan_slab_alloc() and kasan_kmalloc(). Right now we assign a tag twice, once in each of the hooks. Fix it by assigning a tag only in the former hook. Link: http://lkml.kernel.org/r/ce8c6431da735aa7ec051fd6497153df690eb021.1549921721.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>
* numa: change get_mempolicy() to use nr_node_ids instead of MAX_NUMNODESRalph Campbell2019-02-211-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The system call, get_mempolicy() [1], passes an unsigned long *nodemask pointer and an unsigned long maxnode argument which specifies the length of the user's nodemask array in bits (which is rounded up). The manual page says that if the maxnode value is too small, get_mempolicy will return EINVAL but there is no system call to return this minimum value. To determine this value, some programs search /proc/<pid>/status for a line starting with "Mems_allowed:" and use the number of digits in the mask to determine the minimum value. A recent change to the way this line is formatted [2] causes these programs to compute a value less than MAX_NUMNODES so get_mempolicy() returns EINVAL. Change get_mempolicy(), the older compat version of get_mempolicy(), and the copy_nodes_to_user() function to use nr_node_ids instead of MAX_NUMNODES, thus preserving the defacto method of computing the minimum size for the nodemask array and the maxnode argument. [1] http://man7.org/linux/man-pages/man2/get_mempolicy.2.html [2] https://lore.kernel.org/lkml/1545405631-6808-1-git-send-email-longman@redhat.com Link: http://lkml.kernel.org/r/20190211180245.22295-1-rcampbell@nvidia.com Fixes: 4fb8e5b89bcbbbb ("include/linux/nodemask.h: use nr_node_ids (not MAX_NUMNODES) in __nodemask_pr_numnodes()") Signed-off-by: Ralph Campbell <rcampbell@nvidia.com> Suggested-by: Alexander Duyck <alexander.duyck@gmail.com> Cc: Waiman Long <longman@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netLinus Torvalds2019-02-191-4/+4
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull networking fixes from David Miller: 1) Fix suspend and resume in mt76x0u USB driver, from Stanislaw Gruszka. 2) Missing memory barriers in xsk, from Magnus Karlsson. 3) rhashtable fixes in mac80211 from Herbert Xu. 4) 32-bit MIPS eBPF JIT fixes from Paul Burton. 5) Fix for_each_netdev_feature() on big endian, from Hauke Mehrtens. 6) GSO validation fixes from Willem de Bruijn. 7) Endianness fix for dwmac4 timestamp handling, from Alexandre Torgue. 8) More strict checks in tcp_v4_err(), from Eric Dumazet. 9) af_alg_release should NULL out the sk after the sock_put(), from Mao Wenan. 10) Missing unlock in mac80211 mesh error path, from Wei Yongjun. 11) Missing device put in hns driver, from Salil Mehta. * git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (44 commits) sky2: Increase D3 delay again vhost: correctly check the return value of translate_desc() in log_used() net: netcp: Fix ethss driver probe issue net: hns: Fixes the missing put_device in positive leg for roce reset net: stmmac: Fix a race in EEE enable callback qed: Fix iWARP syn packet mac address validation. qed: Fix iWARP buffer size provided for syn packet processing. r8152: Add support for MAC address pass through on RTL8153-BD mac80211: mesh: fix missing unlock on error in table_path_del() net/mlx4_en: fix spelling mistake: "quiting" -> "quitting" net: crypto set sk to NULL when af_alg_release. net: Do not allocate page fragments that are not skb aligned mm: Use fixed constant in page_frag_alloc instead of size + 1 tcp: tcp_v4_err() should be more careful tcp: clear icsk_backoff in tcp_write_queue_purge() net: mv643xx_eth: disable clk on error path in mv643xx_eth_shared_probe() qmi_wwan: apply SET_DTR quirk to Sierra WP7607 net: stmmac: handle endianness in dwmac4_get_timestamp doc: Mention MSG_ZEROCOPY implementation for UDP mlxsw: __mlxsw_sp_port_headroom_set(): Fix a use of local variable ...
| * mm: Use fixed constant in page_frag_alloc instead of size + 1Alexander Duyck2019-02-171-4/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch replaces the size + 1 value introduced with the recent fix for 1 byte allocs with a constant value. The idea here is to reduce code overhead as the previous logic would have to read size into a register, then increment it, and write it back to whatever field was being used. By using a constant we can avoid those memory reads and arithmetic operations in favor of just encoding the maximum value into the operation itself. Fixes: 2c2ade81741c ("mm: page_alloc: fix ref bias in page_frag_alloc() for 1-byte allocs") Signed-off-by: Alexander Duyck <alexander.h.duyck@linux.intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* | arm64, mm, efi: Account for GICv3 LPI tables in static memblock reserve tableArd Biesheuvel2019-02-161-2/+9
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In the irqchip and EFI code, we have what basically amounts to a quirk to work around a peculiarity in the GICv3 architecture, which permits the system memory address of LPI tables to be programmable only once after a CPU reset. This means kexec kernels must use the same memory as the first kernel, and thus ensure that this memory has not been given out for other purposes by the time the ITS init code runs, which is not very early for secondary CPUs. On systems with many CPUs, these reservations could overflow the memblock reservation table, and this was addressed in commit: eff896288872 ("efi/arm: Defer persistent reservations until after paging_init()") However, this turns out to have made things worse, since the allocation of page tables and heap space for the resized memblock reservation table itself may overwrite the regions we are attempting to reserve, which may cause all kinds of corruption, also considering that the ITS will still be poking bits into that memory in response to incoming MSIs. So instead, let's grow the static memblock reservation table on such systems so it can accommodate these reservations at an earlier time. This will permit us to revert the above commit in a subsequent patch. [ mingo: Minor cleanups. ] Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Acked-by: Mike Rapoport <rppt@linux.ibm.com> Acked-by: Will Deacon <will.deacon@arm.com> Acked-by: Marc Zyngier <marc.zyngier@arm.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-arm-kernel@lists.infradead.org Cc: linux-efi@vger.kernel.org Link: http://lkml.kernel.org/r/20190215123333.21209-2-ard.biesheuvel@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netLinus Torvalds2019-02-151-4/+4
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull networking fixes from David Miller: 1) Fix MAC address setting in mac80211 pmsr code, from Johannes Berg. 2) Probe SFP modules after being attached, from Russell King. 3) Byte ordering bug in SMC rx_curs_confirmed code, from Ursula Braun. 4) Revert some r8169 changes that are causing regressions, from Heiner Kallweit. 5) Fix spurious connection timeouts in netfilter nat code, from Florian Westphal. 6) SKB leak in tipc, from Hoang Le. 7) Short packet checkum issue in mlx4, similar to a previous mlx5 change, from Saeed Mahameed. The issue is that whilst padding bytes are usually zero, it is not guarateed and the hardware doesn't take the padding bytes into consideration when generating the checksum. 8) Fix various races in cls_tcindex, from Cong Wang. 9) Need to set stream ext to NULL before freeing in SCTP code, from Xin Long. 10) Fix locking in phy_is_started, from Heiner Kallweit. * git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (54 commits) net: ethernet: freescale: set FEC ethtool regs version net: hns: Fix object reference leaks in hns_dsaf_roce_reset() mm: page_alloc: fix ref bias in page_frag_alloc() for 1-byte allocs net: phy: fix potential race in the phylib state machine net: phy: don't use locking in phy_is_started selftests: fix timestamping Makefile net: dsa: bcm_sf2: potential array overflow in bcm_sf2_sw_suspend() net: fix possible overflow in __sk_mem_raise_allocated() dsa: mv88e6xxx: Ensure all pending interrupts are handled prior to exit net: phy: fix interrupt handling in non-started states sctp: set stream ext to NULL after freeing it in sctp_stream_outq_migrate sctp: call gso_reset_checksum when computing checksum in sctp_gso_segment net/mlx5e: XDP, fix redirect resources availability check net/mlx5: Fix a compilation warning in events.c net/mlx5: No command allowed when command interface is not ready net/mlx5e: Fix NULL pointer derefernce in set channels error flow netfilter: nft_compat: use-after-free when deleting targets team: avoid complex list operations in team_nl_cmd_options_set() net_sched: fix two more memory leaks in cls_tcindex net_sched: fix a memory leak in cls_tcindex ...
| * mm: page_alloc: fix ref bias in page_frag_alloc() for 1-byte allocsJann Horn2019-02-141-4/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The basic idea behind ->pagecnt_bias is: If we pre-allocate the maximum number of references that we might need to create in the fastpath later, the bump-allocation fastpath only has to modify the non-atomic bias value that tracks the number of extra references we hold instead of the atomic refcount. The maximum number of allocations we can serve (under the assumption that no allocation is made with size 0) is nc->size, so that's the bias used. However, even when all memory in the allocation has been given away, a reference to the page is still held; and in the `offset < 0` slowpath, the page may be reused if everyone else has dropped their references. This means that the necessary number of references is actually `nc->size+1`. Luckily, from a quick grep, it looks like the only path that can call page_frag_alloc(fragsz=1) is TAP with the IFF_NAPI_FRAGS flag, which requires CAP_NET_ADMIN in the init namespace and is only intended to be used for kernel testing and fuzzing. To test for this issue, put a `WARN_ON(page_ref_count(page) == 0)` in the `offset < 0` path, below the virt_to_page() call, and then repeatedly call writev() on a TAP device with IFF_TAP|IFF_NO_PI|IFF_NAPI_FRAGS|IFF_NAPI, with a vector consisting of 15 elements containing 1 byte each. Signed-off-by: Jann Horn <jannh@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* | Revert "mm: use early_pfn_to_nid in page_ext_init"Qian Cai2019-02-121-3/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This reverts commit fe53ca54270a ("mm: use early_pfn_to_nid in page_ext_init"). When booting a system with "page_owner=on", start_kernel page_ext_init invoke_init_callbacks init_section_page_ext init_page_owner init_early_allocated_pages init_zones_in_node init_pages_in_zone lookup_page_ext page_to_nid The issue here is that page_to_nid() will not work since some page flags have no node information until later in page_alloc_init_late() due to DEFERRED_STRUCT_PAGE_INIT. Hence, it could trigger an out-of-bounds access with an invalid nid. UBSAN: Undefined behaviour in ./include/linux/mm.h:1104:50 index 7 is out of range for type 'zone [5]' Also, kernel will panic since flags were poisoned earlier with, CONFIG_DEBUG_VM_PGFLAGS=y CONFIG_NODE_NOT_IN_PAGE_FLAGS=n start_kernel setup_arch pagetable_init paging_init sparse_init sparse_init_nid memblock_alloc_try_nid_raw It did not handle it well in init_pages_in_zone() which ends up calling page_to_nid(). page:ffffea0004200000 is uninitialized and poisoned raw: ffffffffffffffff ffffffffffffffff ffffffffffffffff ffffffffffffffff raw: ffffffffffffffff ffffffffffffffff ffffffffffffffff ffffffffffffffff page dumped because: VM_BUG_ON_PAGE(PagePoisoned(p)) page_owner info is not active (free page?) kernel BUG at include/linux/mm.h:990! RIP: 0010:init_page_owner+0x486/0x520 This means that assumptions behind commit fe53ca54270a ("mm: use early_pfn_to_nid in page_ext_init") are incomplete. Therefore, revert the commit for now. A proper way to move the page_owner initialization to sooner is to hook into memmap initialization. Link: http://lkml.kernel.org/r/20190115202812.75820-1-cai@lca.pw Signed-off-by: Qian Cai <cai@lca.pw> Acked-by: Michal Hocko <mhocko@kernel.org> Cc: Pasha Tatashin <Pavel.Tatashin@microsoft.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Yang Shi <yang.shi@linaro.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/gup: fix gup_pmd_range() for daxYu Zhao2019-02-121-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | For dax pmd, pmd_trans_huge() returns false but pmd_huge() returns true on x86. So the function works as long as hugetlb is configured. However, dax doesn't depend on hugetlb. Link: http://lkml.kernel.org/r/20190111034033.601-1-yuzhao@google.com Signed-off-by: Yu Zhao <yuzhao@google.com> Reviewed-by: Jan Kara <jack@suse.cz> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Huang Ying <ying.huang@intel.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Keith Busch <keith.busch@intel.com> Cc: "Michael S . Tsirkin" <mst@redhat.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Wei Yang <richard.weiyang@gmail.com> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | Revert "mm: slowly shrink slabs with a relatively small number of objects"Dave Chinner2019-02-121-10/+0
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This reverts commit 172b06c32b9497 ("mm: slowly shrink slabs with a relatively small number of objects"). This change changes the agressiveness of shrinker reclaim, causing small cache and low priority reclaim to greatly increase scanning pressure on small caches. As a result, light memory pressure has a disproportionate affect on small caches, and causes large caches to be reclaimed much faster than previously. As a result, it greatly perturbs the delicate balance of the VFS caches (dentry/inode vs file page cache) such that the inode/dentry caches are reclaimed much, much faster than the page cache and this drives us into several other caching imbalance related problems. As such, this is a bad change and needs to be reverted. [ Needs some massaging to retain the later seekless shrinker modifications.] Link: http://lkml.kernel.org/r/20190130041707.27750-3-david@fromorbit.com Fixes: 172b06c32b9497 ("mm: slowly shrink slabs with a relatively small number of objects") Signed-off-by: Dave Chinner <dchinner@redhat.com> Cc: Wolfgang Walter <linux@stwm.de> Cc: Roman Gushchin <guro@fb.com> Cc: Spock <dairinin@gmail.com> Cc: Rik van Riel <riel@surriel.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: migrate: don't rely on __PageMovable() of newpage after unlocking itDavid Hildenbrand2019-02-011-2/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We had a race in the old balloon compaction code before b1123ea6d3b3 ("mm: balloon: use general non-lru movable page feature") refactored it that became visible after backporting 195a8c43e93d ("virtio-balloon: deflate via a page list") without the refactoring. The bug existed from commit d6d86c0a7f8d ("mm/balloon_compaction: redesign ballooned pages management") till b1123ea6d3b3 ("mm: balloon: use general non-lru movable page feature"). d6d86c0a7f8d ("mm/balloon_compaction: redesign ballooned pages management") was backported to 3.12, so the broken kernels are stable kernels [3.12 - 4.7]. There was a subtle race between dropping the page lock of the newpage in __unmap_and_move() and checking for __is_movable_balloon_page(newpage). Just after dropping this page lock, virtio-balloon could go ahead and deflate the newpage, effectively dequeueing it and clearing PageBalloon, in turn making __is_movable_balloon_page(newpage) fail. This resulted in dropping the reference of the newpage via putback_lru_page(newpage) instead of put_page(newpage), leading to page->lru getting modified and a !LRU page ending up in the LRU lists. With 195a8c43e93d ("virtio-balloon: deflate via a page list") backported, one would suddenly get corrupted lists in release_pages_balloon(): - WARNING: CPU: 13 PID: 6586 at lib/list_debug.c:59 __list_del_entry+0xa1/0xd0 - list_del corruption. prev->next should be ffffe253961090a0, but was dead000000000100 Nowadays this race is no longer possible, but it is hidden behind very ugly handling of __ClearPageMovable() and __PageMovable(). __ClearPageMovable() will not make __PageMovable() fail, only PageMovable(). So the new check (__PageMovable(newpage)) will still hold even after newpage was dequeued by virtio-balloon. If anybody would ever change that special handling, the BUG would be introduced again. So instead, make it explicit and use the information of the original isolated page before migration. This patch can be backported fairly easy to stable kernels (in contrast to the refactoring). Link: http://lkml.kernel.org/r/20190129233217.10747-1-david@redhat.com Fixes: d6d86c0a7f8d ("mm/balloon_compaction: redesign ballooned pages management") Signed-off-by: David Hildenbrand <david@redhat.com> Reported-by: Vratislav Bendel <vbendel@redhat.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Rafael Aquini <aquini@redhat.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Jan Kara <jack@suse.cz> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Dominik Brodowski <linux@dominikbrodowski.net> Cc: Matthew Wilcox <willy@infradead.org> Cc: Vratislav Bendel <vbendel@redhat.com> Cc: Rafael Aquini <aquini@redhat.com> Cc: Konstantin Khlebnikov <k.khlebnikov@samsung.com> Cc: Minchan Kim <minchan@kernel.org> Cc: <stable@vger.kernel.org> [3.12 - 4.7] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm, memory_hotplug: __offline_pages fix wrong lockingMichal Hocko2019-02-011-2/+0
| | | | | | | | | | | | | | | | | | | | | Jan has noticed that we do double unlock on some failure paths when offlining a page range. This is indeed the case when test_pages_in_a_zone respp. start_isolate_page_range fail. This was an omission when forward porting the debugging patch from an older kernel. Fix the issue by dropping mem_hotplug_done from the failure condition and keeping the single unlock in the catch all failure path. Link: http://lkml.kernel.org/r/20190115120307.22768-1-mhocko@kernel.org Fixes: 7960509329c2 ("mm, memory_hotplug: print reason for the offlining failure") Signed-off-by: Michal Hocko <mhocko@suse.com> Reported-by: Jan Kara <jack@suse.cz> Reviewed-by: Jan Kara <jack@suse.cz> Tested-by: Jan Kara <jack@suse.cz> Reviewed-by: Oscar Salvador <osalvador@suse.de> 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: hwpoison: use do_send_sig_info() instead of force_sig()Naoya Horiguchi2019-02-011-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently memory_failure() is racy against process's exiting, which results in kernel crash by null pointer dereference. The root cause is that memory_failure() uses force_sig() to forcibly kill asynchronous (meaning not in the current context) processes. As discussed in thread https://lkml.org/lkml/2010/6/8/236 years ago for OOM fixes, this is not a right thing to do. OOM solves this issue by using do_send_sig_info() as done in commit d2d393099de2 ("signal: oom_kill_task: use SEND_SIG_FORCED instead of force_sig()"), so this patch is suggesting to do the same for hwpoison. do_send_sig_info() properly accesses to siglock with lock_task_sighand(), so is free from the reported race. I confirmed that the reported bug reproduces with inserting some delay in kill_procs(), and it never reproduces with this patch. Note that memory_failure() can send another type of signal using force_sig_mceerr(), and the reported race shouldn't happen on it because force_sig_mceerr() is called only for synchronous processes (i.e. BUS_MCEERR_AR happens only when some process accesses to the corrupted memory.) Link: http://lkml.kernel.org/r/20190116093046.GA29835@hori1.linux.bs1.fc.nec.co.jp Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Reported-by: Jane Chu <jane.chu@oracle.com> Reviewed-by: Dan Williams <dan.j.williams@intel.com> Reviewed-by: William Kucharski <william.kucharski@oracle.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* kasan: mark file common so ftrace doesn't trace itAnders Roxell2019-02-011-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When option CONFIG_KASAN is enabled toghether with ftrace, function ftrace_graph_caller() gets in to a recursion, via functions kasan_check_read() and kasan_check_write(). Breakpoint 2, ftrace_graph_caller () at ../arch/arm64/kernel/entry-ftrace.S:179 179 mcount_get_pc x0 // function's pc (gdb) bt #0 ftrace_graph_caller () at ../arch/arm64/kernel/entry-ftrace.S:179 #1 0xffffff90101406c8 in ftrace_caller () at ../arch/arm64/kernel/entry-ftrace.S:151 #2 0xffffff90106fd084 in kasan_check_write (p=0xffffffc06c170878, size=4) at ../mm/kasan/common.c:105 #3 0xffffff90104a2464 in atomic_add_return (v=<optimized out>, i=<optimized out>) at ./include/generated/atomic-instrumented.h:71 #4 atomic_inc_return (v=<optimized out>) at ./include/generated/atomic-fallback.h:284 #5 trace_graph_entry (trace=0xffffffc03f5ff380) at ../kernel/trace/trace_functions_graph.c:441 #6 0xffffff9010481774 in trace_graph_entry_watchdog (trace=<optimized out>) at ../kernel/trace/trace_selftest.c:741 #7 0xffffff90104a185c in function_graph_enter (ret=<optimized out>, func=<optimized out>, frame_pointer=18446743799894897728, retp=<optimized out>) at ../kernel/trace/trace_functions_graph.c:196 #8 0xffffff9010140628 in prepare_ftrace_return (self_addr=18446743592948977792, parent=0xffffffc03f5ff418, frame_pointer=18446743799894897728) at ../arch/arm64/kernel/ftrace.c:231 #9 0xffffff90101406f4 in ftrace_graph_caller () at ../arch/arm64/kernel/entry-ftrace.S:182 Backtrace stopped: previous frame identical to this frame (corrupt stack?) (gdb) Rework so that the kasan implementation isn't traced. Link: http://lkml.kernel.org/r/20181212183447.15890-1-anders.roxell@linaro.org Signed-off-by: Anders Roxell <anders.roxell@linaro.org> Acked-by: Dmitry Vyukov <dvyukov@google.com> Tested-by: Dmitry Vyukov <dvyukov@google.com> Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.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, oom: fix use-after-free in oom_kill_processShakeel Butt2019-02-011-0/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Syzbot instance running on upstream kernel found a use-after-free bug in oom_kill_process. On further inspection it seems like the process selected to be oom-killed has exited even before reaching read_lock(&tasklist_lock) in oom_kill_process(). More specifically the tsk->usage is 1 which is due to get_task_struct() in oom_evaluate_task() and the put_task_struct within for_each_thread() frees the tsk and for_each_thread() tries to access the tsk. The easiest fix is to do get/put across the for_each_thread() on the selected task. Now the next question is should we continue with the oom-kill as the previously selected task has exited? However before adding more complexity and heuristics, let's answer why we even look at the children of oom-kill selected task? The select_bad_process() has already selected the worst process in the system/memcg. Due to race, the selected process might not be the worst at the kill time but does that matter? The userspace can use the oom_score_adj interface to prefer children to be killed before the parent. I looked at the history but it seems like this is there before git history. Link: http://lkml.kernel.org/r/20190121215850.221745-1-shakeelb@google.com Reported-by: syzbot+7fbbfa368521945f0e3d@syzkaller.appspotmail.com Fixes: 6b0c81b3be11 ("mm, oom: reduce dependency on tasklist_lock") Signed-off-by: Shakeel Butt <shakeelb@google.com> Reviewed-by: Roman Gushchin <guro@fb.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: David Rientjes <rientjes@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm,memory_hotplug: fix scan_movable_pages() for gigantic hugepagesOscar Salvador2019-02-011-16/+20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This is the same sort of error we saw in commit 17e2e7d7e1b8 ("mm, page_alloc: fix has_unmovable_pages for HugePages"). Gigantic hugepages cross several memblocks, so it can be that the page we get in scan_movable_pages() is a page-tail belonging to a 1G-hugepage. If that happens, page_hstate()->size_to_hstate() will return NULL, and we will blow up in hugepage_migration_supported(). The splat is as follows: BUG: unable to handle kernel NULL pointer dereference at 0000000000000008 #PF error: [normal kernel read fault] PGD 0 P4D 0 Oops: 0000 [#1] SMP PTI CPU: 1 PID: 1350 Comm: bash Tainted: G E 5.0.0-rc1-mm1-1-default+ #27 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.0.0-prebuilt.qemu-project.org 04/01/2014 RIP: 0010:__offline_pages+0x6ae/0x900 Call Trace: memory_subsys_offline+0x42/0x60 device_offline+0x80/0xa0 state_store+0xab/0xc0 kernfs_fop_write+0x102/0x180 __vfs_write+0x26/0x190 vfs_write+0xad/0x1b0 ksys_write+0x42/0x90 do_syscall_64+0x5b/0x180 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Modules linked in: af_packet(E) xt_tcpudp(E) ipt_REJECT(E) xt_conntrack(E) nf_conntrack(E) nf_defrag_ipv4(E) ip_set(E) nfnetlink(E) ebtable_nat(E) ebtable_broute(E) bridge(E) stp(E) llc(E) iptable_mangle(E) iptable_raw(E) iptable_security(E) ebtable_filter(E) ebtables(E) iptable_filter(E) ip_tables(E) x_tables(E) kvm_intel(E) kvm(E) irqbypass(E) crct10dif_pclmul(E) crc32_pclmul(E) ghash_clmulni_intel(E) bochs_drm(E) ttm(E) aesni_intel(E) drm_kms_helper(E) aes_x86_64(E) crypto_simd(E) cryptd(E) glue_helper(E) drm(E) virtio_net(E) syscopyarea(E) sysfillrect(E) net_failover(E) sysimgblt(E) pcspkr(E) failover(E) i2c_piix4(E) fb_sys_fops(E) parport_pc(E) parport(E) button(E) btrfs(E) libcrc32c(E) xor(E) zstd_decompress(E) zstd_compress(E) xxhash(E) raid6_pq(E) sd_mod(E) ata_generic(E) ata_piix(E) ahci(E) libahci(E) libata(E) crc32c_intel(E) serio_raw(E) virtio_pci(E) virtio_ring(E) virtio(E) sg(E) scsi_mod(E) autofs4(E) [akpm@linux-foundation.org: fix brace layout, per David. Reduce indentation] Link: http://lkml.kernel.org/r/20190122154407.18417-1-osalvador@suse.de Signed-off-by: Oscar Salvador <osalvador@suse.de> Reviewed-by: Anthony Yznaga <anthony.yznaga@oracle.com> Acked-by: Michal Hocko <mhocko@suse.com> Reviewed-by: David Hildenbrand <david@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm, memory_hotplug: test_pages_in_a_zone do not pass the end of zoneMikhail Zaslonko2019-02-011-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If memory end is not aligned with the sparse memory section boundary, the mapping of such a section is only partly initialized. This may lead to VM_BUG_ON due to uninitialized struct pages access from test_pages_in_a_zone() function triggered by memory_hotplug sysfs handlers. Here are the the panic examples: CONFIG_DEBUG_VM_PGFLAGS=y kernel parameter mem=2050M -------------------------- page:000003d082008000 is uninitialized and poisoned page dumped because: VM_BUG_ON_PAGE(PagePoisoned(p)) Call Trace: test_pages_in_a_zone+0xde/0x160 show_valid_zones+0x5c/0x190 dev_attr_show+0x34/0x70 sysfs_kf_seq_show+0xc8/0x148 seq_read+0x204/0x480 __vfs_read+0x32/0x178 vfs_read+0x82/0x138 ksys_read+0x5a/0xb0 system_call+0xdc/0x2d8 Last Breaking-Event-Address: test_pages_in_a_zone+0xde/0x160 Kernel panic - not syncing: Fatal exception: panic_on_oops Fix this by checking whether the pfn to check is within the zone. [mhocko@suse.com: separated this change from http://lkml.kernel.org/r/20181105150401.97287-2-zaslonko@linux.ibm.com] Link: http://lkml.kernel.org/r/20190128144506.15603-3-mhocko@kernel.org [mhocko@suse.com: separated this change from http://lkml.kernel.org/r/20181105150401.97287-2-zaslonko@linux.ibm.com] Signed-off-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Mikhail Zaslonko <zaslonko@linux.ibm.com> Tested-by: Mikhail Gavrilov <mikhail.v.gavrilov@gmail.com> Reviewed-by: Oscar Salvador <osalvador@suse.de> Tested-by: Gerald Schaefer <gerald.schaefer@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Mikhail Gavrilov <mikhail.v.gavrilov@gmail.com> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm, memory_hotplug: is_mem_section_removable do not pass the end of a zoneMichal Hocko2019-02-011-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Patch series "mm, memory_hotplug: fix uninitialized pages fallouts", v2. Mikhail Zaslonko has posted fixes for the two bugs quite some time ago [1]. I have pushed back on those fixes because I believed that it is much better to plug the problem at the initialization time rather than play whack-a-mole all over the hotplug code and find all the places which expect the full memory section to be initialized. We have ended up with commit 2830bf6f05fb ("mm, memory_hotplug: initialize struct pages for the full memory section") merged and cause a regression [2][3]. The reason is that there might be memory layouts when two NUMA nodes share the same memory section so the merged fix is simply incorrect. In order to plug this hole we really have to be zone range aware in those handlers. I have split up the original patch into two. One is unchanged (patch 2) and I took a different approach for `removable' crash. [1] http://lkml.kernel.org/r/20181105150401.97287-2-zaslonko@linux.ibm.com [2] https://bugzilla.redhat.com/show_bug.cgi?id=1666948 [3] http://lkml.kernel.org/r/20190125163938.GA20411@dhcp22.suse.cz This patch (of 2): Mikhail has reported the following VM_BUG_ON triggered when reading sysfs removable state of a memory block: page:000003d08300c000 is uninitialized and poisoned page dumped because: VM_BUG_ON_PAGE(PagePoisoned(p)) Call Trace: is_mem_section_removable+0xb4/0x190 show_mem_removable+0x9a/0xd8 dev_attr_show+0x34/0x70 sysfs_kf_seq_show+0xc8/0x148 seq_read+0x204/0x480 __vfs_read+0x32/0x178 vfs_read+0x82/0x138 ksys_read+0x5a/0xb0 system_call+0xdc/0x2d8 Last Breaking-Event-Address: is_mem_section_removable+0xb4/0x190 Kernel panic - not syncing: Fatal exception: panic_on_oops The reason is that the memory block spans the zone boundary and we are stumbling over an unitialized struct page. Fix this by enforcing zone range in is_mem_section_removable so that we never run away from a zone. Link: http://lkml.kernel.org/r/20190128144506.15603-2-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Reported-by: Mikhail Zaslonko <zaslonko@linux.ibm.com> Debugged-by: Mikhail Zaslonko <zaslonko@linux.ibm.com> Tested-by: Gerald Schaefer <gerald.schaefer@de.ibm.com> Tested-by: Mikhail Gavrilov <mikhail.v.gavrilov@gmail.com> Reviewed-by: Oscar Salvador <osalvador@suse.de> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* oom, oom_reaper: do not enqueue same task twiceTetsuo Handa2019-02-011-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Arkadiusz reported that enabling memcg's group oom killing causes strange memcg statistics where there is no task in a memcg despite the number of tasks in that memcg is not 0. It turned out that there is a bug in wake_oom_reaper() which allows enqueuing same task twice which makes impossible to decrease the number of tasks in that memcg due to a refcount leak. This bug existed since the OOM reaper became invokable from task_will_free_mem(current) path in out_of_memory() in Linux 4.7, T1@P1 |T2@P1 |T3@P1 |OOM reaper ----------+----------+----------+------------ # Processing an OOM victim in a different memcg domain. try_charge() mem_cgroup_out_of_memory() mutex_lock(&oom_lock) try_charge() mem_cgroup_out_of_memory() mutex_lock(&oom_lock) try_charge() mem_cgroup_out_of_memory() mutex_lock(&oom_lock) out_of_memory() oom_kill_process(P1) do_send_sig_info(SIGKILL, @P1) mark_oom_victim(T1@P1) wake_oom_reaper(T1@P1) # T1@P1 is enqueued. mutex_unlock(&oom_lock) out_of_memory() mark_oom_victim(T2@P1) wake_oom_reaper(T2@P1) # T2@P1 is enqueued. mutex_unlock(&oom_lock) out_of_memory() mark_oom_victim(T1@P1) wake_oom_reaper(T1@P1) # T1@P1 is enqueued again due to oom_reaper_list == T2@P1 && T1@P1->oom_reaper_list == NULL. mutex_unlock(&oom_lock) # Completed processing an OOM victim in a different memcg domain. spin_lock(&oom_reaper_lock) # T1P1 is dequeued. spin_unlock(&oom_reaper_lock) but memcg's group oom killing made it easier to trigger this bug by calling wake_oom_reaper() on the same task from one out_of_memory() request. Fix this bug using an approach used by commit 855b018325737f76 ("oom, oom_reaper: disable oom_reaper for oom_kill_allocating_task"). As a side effect of this patch, this patch also avoids enqueuing multiple threads sharing memory via task_will_free_mem(current) path. Link: http://lkml.kernel.org/r/e865a044-2c10-9858-f4ef-254bc71d6cc2@i-love.sakura.ne.jp Link: http://lkml.kernel.org/r/5ee34fc6-1485-34f8-8790-903ddabaa809@i-love.sakura.ne.jp Fixes: af8e15cc85a25315 ("oom, oom_reaper: do not enqueue task if it is on the oom_reaper_list head") Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Reported-by: Arkadiusz Miskiewicz <arekm@maven.pl> Tested-by: Arkadiusz Miskiewicz <arekm@maven.pl> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Roman Gushchin <guro@fb.com> Cc: Tejun Heo <tj@kernel.org> Cc: Aleksa Sarai <asarai@suse.de> Cc: Jay Kamat <jgkamat@fb.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: migrate: make buffer_migrate_page_norefs() actually succeedJan Kara2019-02-011-5/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, buffer_migrate_page_norefs() was constantly failing because buffer_migrate_lock_buffers() grabbed reference on each buffer. In fact, there's no reason for buffer_migrate_lock_buffers() to grab any buffer references as the page is locked during all our operation and thus nobody can reclaim buffers from the page. So remove grabbing of buffer references which also makes buffer_migrate_page_norefs() succeed. Link: http://lkml.kernel.org/r/20190116131217.7226-1-jack@suse.cz Fixes: 89cb0888ca14 "mm: migrate: provide buffer_migrate_page_norefs()" Signed-off-by: Jan Kara <jack@suse.cz> Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> Cc: Pavel Machek <pavel@ucw.cz> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: David Rientjes <rientjes@google.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Zi Yan <zi.yan@cs.rutgers.edu> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/hugetlb.c: teach follow_hugetlb_page() to handle FOLL_NOWAITAndrea Arcangeli2019-02-011-1/+2
| | | | | | | | | | | | | | | | | | | | hugetlb needs the same fix as faultin_nopage (which was applied in commit 96312e61282a ("mm/gup.c: teach get_user_pages_unlocked to handle FOLL_NOWAIT")) or KVM hangs because it thinks the mmap_sem was already released by hugetlb_fault() if it returned VM_FAULT_RETRY, but it wasn't in the FOLL_NOWAIT case. Link: http://lkml.kernel.org/r/20190109020203.26669-2-aarcange@redhat.com Fixes: ce53053ce378 ("kvm: switch get_user_page_nowait() to get_user_pages_unlocked()") Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Tested-by: "Dr. David Alan Gilbert" <dgilbert@redhat.com> Reported-by: "Dr. David Alan Gilbert" <dgilbert@redhat.com> Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com> Reviewed-by: Peter Xu <peterx@redhat.com> Cc: Mike Rapoport <rppt@linux.vnet.ibm.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm, memory_hotplug: don't bail out in do_migrate_range() prematurelyOscar Salvador2019-02-011-16/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | do_migrate_range() takes a memory range and tries to isolate the pages to put them into a list. This list will be later on used in migrate_pages() to know the pages we need to migrate. Currently, if we fail to isolate a single page, we put all already isolated pages back to their LRU and we bail out from the function. This is quite suboptimal, as this will force us to start over again because scan_movable_pages will give us the same range. If there is no chance that we can isolate that page, we will loop here forever. Issue debugged in [1] has proved that. During the debugging of that issue, it was noticed that if do_migrate_ranges() fails to isolate a single page, we will just discard the work we have done so far and bail out, which means that scan_movable_pages() will find again the same set of pages. Instead, we can just skip the error, keep isolating as much pages as possible and then proceed with the call to migrate_pages(). This will allow us to do as much work as possible at once. [1] https://lkml.org/lkml/2018/12/6/324 Michal said: : I still think that this doesn't give us a whole picture. Looping for : ever is a bug. Failing the isolation is quite possible and it should : be a ephemeral condition (e.g. a race with freeing the page or : somebody else isolating the page for whatever reason). And here comes : the disadvantage of the current implementation. We simply throw : everything on the floor just because of a ephemeral condition. The : racy page_count check is quite dubious to prevent from that. Link: http://lkml.kernel.org/r/20181211135312.27034-1-osalvador@suse.de Signed-off-by: Oscar Salvador <osalvador@suse.de> Acked-by: Michal Hocko <mhocko@suse.com> Cc: David Hildenbrand <david@redhat.com> Cc: Dan Williams <dan.j.williams@gmail.com> Cc: Jan Kara <jack@suse.cz> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: William Kucharski <william.kucharski@oracle.com> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Revert "mm, memory_hotplug: initialize struct pages for the full memory section"Michal Hocko2019-01-281-12/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This reverts commit 2830bf6f05fb3e05bc4743274b806c821807a684. The underlying assumption that one sparse section belongs into a single numa node doesn't hold really. Robert Shteynfeld has reported a boot failure. The boot log was not captured but his memory layout is as follows: Early memory node ranges node 1: [mem 0x0000000000001000-0x0000000000090fff] node 1: [mem 0x0000000000100000-0x00000000dbdf8fff] node 1: [mem 0x0000000100000000-0x0000001423ffffff] node 0: [mem 0x0000001424000000-0x0000002023ffffff] This means that node0 starts in the middle of a memory section which is also in node1. memmap_init_zone tries to initialize padding of a section even when it is outside of the given pfn range because there are code paths (e.g. memory hotplug) which assume that the full worth of memory section is always initialized. In this particular case, though, such a range is already intialized and most likely already managed by the page allocator. Scribbling over those pages corrupts the internal state and likely blows up when any of those pages gets used. Reported-by: Robert Shteynfeld <robert.shteynfeld@gmail.com> Fixes: 2830bf6f05fb ("mm, memory_hotplug: initialize struct pages for the full memory section") Cc: stable@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge tag 'for-linus-20190125' of git://git.kernel.dk/linux-blockLinus Torvalds2019-01-261-0/+1
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull block fixes from Jens Axboe: "A collection of fixes for this release. This contains: - Silence sparse rightfully complaining about non-static wbt functions (Bart) - Fixes for the zoned comments/ioctl documentation (Damien) - direct-io fix that's been lingering for a while (Ernesto) - cgroup writeback fix (Tejun) - Set of NVMe patches for nvme-rdma/tcp (Sagi, Hannes, Raju) - Block recursion tracking fix (Ming) - Fix debugfs command flag naming for a few flags (Jianchao)" * tag 'for-linus-20190125' of git://git.kernel.dk/linux-block: block: Fix comment typo uapi: fix ioctl documentation blk-wbt: Declare local functions static blk-mq: fix the cmd_flag_name array nvme-multipath: drop optimization for static ANA group IDs nvmet-rdma: fix null dereference under heavy load nvme-rdma: rework queue maps handling nvme-tcp: fix timeout handler nvme-rdma: fix timeout handler writeback: synchronize sync(2) against cgroup writeback membership switches block: cover another queue enter recursion via BIO_QUEUE_ENTERED direct-io: allow direct writes to empty inodes
| * writeback: synchronize sync(2) against cgroup writeback membership switchesTejun Heo2019-01-221-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | sync_inodes_sb() can race against cgwb (cgroup writeback) membership switches and fail to writeback some inodes. For example, if an inode switches to another wb while sync_inodes_sb() is in progress, the new wb might not be visible to bdi_split_work_to_wbs() at all or the inode might jump from a wb which hasn't issued writebacks yet to one which already has. This patch adds backing_dev_info->wb_switch_rwsem to synchronize cgwb switch path against sync_inodes_sb() so that sync_inodes_sb() is guaranteed to see all the target wbs and inodes can't jump wbs to escape syncing. v2: Fixed misplaced rwsem init. Spotted by Jiufei. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Jiufei Xue <xuejiufei@gmail.com> Link: http://lkml.kernel.org/r/dc694ae2-f07f-61e1-7097-7c8411cee12d@gmail.com Acked-by: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* | Revert "Change mincore() to count "mapped" pages rather than "cached" pages"Linus Torvalds2019-01-241-13/+81
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This reverts commit 574823bfab82d9d8fa47f422778043fbb4b4f50e. It turns out that my hope that we could just remove the code that exposes the cache residency status from mincore() was too optimistic. There are various random users that want it, and one example would be the Netflix database cluster maintenance. To quote Josh Snyder: "For Netflix, losing accurate information from the mincore syscall would lengthen database cluster maintenance operations from days to months. We rely on cross-process mincore to migrate the contents of a page cache from machine to machine, and across reboots. To do this, I wrote and maintain happycache [1], a page cache dumper/loader tool. It is quite similar in architecture to pgfincore, except that it is agnostic to workload. The gist of happycache's operation is "produce a dump of residence status for each page, do some operation, then reload exactly the same pages which were present before." happycache is entirely dependent on accurate reporting of the in-core status of file-backed pages, as accessed by another process. We primarily use happycache with Cassandra, which (like Postgres + pgfincore) relies heavily on OS page cache to reduce disk accesses. Because our workloads never experience a cold page cache, we are able to provision hardware for a peak utilization level that is far lower than the hypothetical "every query is a cache miss" peak. A database warmed by happycache can be ready for service in seconds (bounded only by the performance of the drives and the I/O subsystem), with no period of in-service degradation. By contrast, putting a database in service without a page cache entails a potentially unbounded period of degradation (at Netflix, the time to populate a single node's cache via natural cache misses varies by workload from hours to weeks). If a single node upgrade were to take weeks, then upgrading an entire cluster would take months. Since we want to apply security upgrades (and other things) on a somewhat tighter schedule, we would have to develop more complex solutions to provide the same functionality already provided by mincore. At the bottom line, happycache is designed to benignly exploit the same information leak documented in the paper [2]. I think it makes perfect sense to remove cross-process mincore functionality from unprivileged users, but not to remove it entirely" We do have an alternate approach that limits the cache residency reporting only to processes that have write permissions to the file, so we can fix the original information leak issue that way. It involves _adding_ code rather than removing it, which is sad, but hey, at least we haven't found any users that would find the restrictions unacceptable. So revert the optimistic first approach to make room for that alternate fix instead. Reported-by: Josh Snyder <joshs@netflix.com> Cc: Jiri Kosina <jikos@kernel.org> Cc: Dominique Martinet <asmadeus@codewreck.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Dave Chinner <david@fromorbit.com> Cc: Kevin Easton <kevin@guarana.org> Cc: Matthew Wilcox <willy@infradead.org> Cc: Cyril Hrubis <chrubis@suse.cz> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Tejun Heo <tj@kernel.org> Cc: Kirill A. Shutemov <kirill@shutemov.name> Cc: Daniel Gruss <daniel@gruss.cc> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | mm/mmu_notifier: mm/rmap.c: Fix a mmu_notifier range bug in try_to_unmap_oneSean Christopherson2019-01-101-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The conversion to use a structure for mmu_notifier_invalidate_range_*() unintentionally changed the usage in try_to_unmap_one() to init the 'struct mmu_notifier_range' with vma->vm_start instead of @address, i.e. it invalidates the wrong address range. Revert to the correct address range. Manifests as KVM use-after-free WARNINGs and subsequent "BUG: Bad page state in process X" errors when reclaiming from a KVM guest due to KVM removing the wrong pages from its own mappings. Reported-by: leozinho29_eu@hotmail.com Reported-by: Mike Galbraith <efault@gmx.de> Reported-and-tested-by: Adam Borowski <kilobyte@angband.pl> Reviewed-by: Jérôme Glisse <jglisse@redhat.com> Reviewed-by: Pankaj gupta <pagupta@redhat.com> Cc: Christian König <christian.koenig@amd.com> Cc: Jan Kara <jack@suse.cz> Cc: Matthew Wilcox <mawilcox@microsoft.com> Cc: Ross Zwisler <zwisler@kernel.org> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Radim Krčmář <rkrcmar@redhat.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Felix Kuehling <felix.kuehling@amd.com> Cc: Ralph Campbell <rcampbell@nvidia.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Andrew Morton <akpm@linux-foundation.org> Fixes: ac46d4f3c432 ("mm/mmu_notifier: use structure for invalidate_range_start/end calls v2") Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | mm, page_alloc: do not wake kswapd with zone lock heldMel Gorman2019-01-081-1/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | syzbot reported the following regression in the latest merge window and it was confirmed by Qian Cai that a similar bug was visible from a different context. ====================================================== WARNING: possible circular locking dependency detected 4.20.0+ #297 Not tainted ------------------------------------------------------ syz-executor0/8529 is trying to acquire lock: 000000005e7fb829 (&pgdat->kswapd_wait){....}, at: __wake_up_common_lock+0x19e/0x330 kernel/sched/wait.c:120 but task is already holding lock: 000000009bb7bae0 (&(&zone->lock)->rlock){-.-.}, at: spin_lock include/linux/spinlock.h:329 [inline] 000000009bb7bae0 (&(&zone->lock)->rlock){-.-.}, at: rmqueue_bulk mm/page_alloc.c:2548 [inline] 000000009bb7bae0 (&(&zone->lock)->rlock){-.-.}, at: __rmqueue_pcplist mm/page_alloc.c:3021 [inline] 000000009bb7bae0 (&(&zone->lock)->rlock){-.-.}, at: rmqueue_pcplist mm/page_alloc.c:3050 [inline] 000000009bb7bae0 (&(&zone->lock)->rlock){-.-.}, at: rmqueue mm/page_alloc.c:3072 [inline] 000000009bb7bae0 (&(&zone->lock)->rlock){-.-.}, at: get_page_from_freelist+0x1bae/0x52a0 mm/page_alloc.c:3491 It appears to be a false positive in that the only way the lock ordering should be inverted is if kswapd is waking itself and the wakeup allocates debugging objects which should already be allocated if it's kswapd doing the waking. Nevertheless, the possibility exists and so it's best to avoid the problem. This patch flags a zone as needing a kswapd using the, surprisingly, unused zone flag field. The flag is read without the lock held to do the wakeup. It's possible that the flag setting context is not the same as the flag clearing context or for small races to occur. However, each race possibility is harmless and there is no visible degredation in fragmentation treatment. While zone->flag could have continued to be unused, there is potential for moving some existing fields into the flags field instead. Particularly read-mostly ones like zone->initialized and zone->contiguous. Link: http://lkml.kernel.org/r/20190103225712.GJ31517@techsingularity.net Fixes: 1c30844d2dfe ("mm: reclaim small amounts of memory when an external fragmentation event occurs") Reported-by: syzbot+93d94a001cfbce9e60e1@syzkaller.appspotmail.com Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Vlastimil Babka <vbabka@suse.cz> Tested-by: Qian Cai <cai@lca.pw> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Michal Hocko <mhocko@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | hugetlbfs: revert "use i_mmap_rwsem for more pmd sharing synchronization"Mike Kravetz2019-01-085-88/+20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This reverts b43a9990055958e70347c56f90ea2ae32c67334c The reverted commit caused issues with migration and poisoning of anon huge pages. The LTP move_pages12 test will cause an "unable to handle kernel NULL pointer" BUG would occur with stack similar to: RIP: 0010:down_write+0x1b/0x40 Call Trace: migrate_pages+0x81f/0xb90 __ia32_compat_sys_migrate_pages+0x190/0x190 do_move_pages_to_node.isra.53.part.54+0x2a/0x50 kernel_move_pages+0x566/0x7b0 __x64_sys_move_pages+0x24/0x30 do_syscall_64+0x5b/0x180 entry_SYSCALL_64_after_hwframe+0x44/0xa9 The purpose of the reverted patch was to fix some long existing races with huge pmd sharing. It used i_mmap_rwsem for this purpose with the idea that this could also be used to address truncate/page fault races with another patch. Further analysis has determined that i_mmap_rwsem can not be used to address all these hugetlbfs synchronization issues. Therefore, revert this patch while working an another approach to the underlying issues. Link: http://lkml.kernel.org/r/20190103235452.29335-2-mike.kravetz@oracle.com Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com> Reported-by: Jan Stancek <jstancek@redhat.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Hugh Dickins <hughd@google.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: "Aneesh Kumar K . V" <aneesh.kumar@linux.vnet.ibm.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Prakash Sangappa <prakash.sangappa@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | hugetlbfs: revert "Use i_mmap_rwsem to fix page fault/truncate race"Mike Kravetz2019-01-081-10/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This reverts c86aa7bbfd5568ba8a82d3635d8f7b8a8e06fe54 The reverted commit caused ABBA deadlocks when file migration raced with file eviction for specific hugetlbfs files. This was discovered with a modified version of the LTP move_pages12 test. The purpose of the reverted patch was to close a long existing race between hugetlbfs file truncation and page faults. After more analysis of the patch and impacted code, it was determined that i_mmap_rwsem can not be used for all required synchronization. Therefore, revert this patch while working an another approach to the underlying issue. Link: http://lkml.kernel.org/r/20190103235452.29335-1-mike.kravetz@oracle.com Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com> Reported-by: Jan Stancek <jstancek@redhat.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Hugh Dickins <hughd@google.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: "Aneesh Kumar K . V" <aneesh.kumar@linux.vnet.ibm.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Prakash Sangappa <prakash.sangappa@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | mm: page_mapped: don't assume compound page is huge or THPJan Stancek2019-01-081-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | LTP proc01 testcase has been observed to rarely trigger crashes on arm64: page_mapped+0x78/0xb4 stable_page_flags+0x27c/0x338 kpageflags_read+0xfc/0x164 proc_reg_read+0x7c/0xb8 __vfs_read+0x58/0x178 vfs_read+0x90/0x14c SyS_read+0x60/0xc0 The issue is that page_mapped() assumes that if compound page is not huge, then it must be THP. But if this is 'normal' compound page (COMPOUND_PAGE_DTOR), then following loop can keep running (for HPAGE_PMD_NR iterations) until it tries to read from memory that isn't mapped and triggers a panic: for (i = 0; i < hpage_nr_pages(page); i++) { if (atomic_read(&page[i]._mapcount) >= 0) return true; } I could replicate this on x86 (v4.20-rc4-98-g60b548237fed) only with a custom kernel module [1] which: - allocates compound page (PAGEC) of order 1 - allocates 2 normal pages (COPY), which are initialized to 0xff (to satisfy _mapcount >= 0) - 2 PAGEC page structs are copied to address of first COPY page - second page of COPY is marked as not present - call to page_mapped(COPY) now triggers fault on access to 2nd COPY page at offset 0x30 (_mapcount) [1] https://github.com/jstancek/reproducers/blob/master/kernel/page_mapped_crash/repro.c Fix the loop to iterate for "1 << compound_order" pages. Kirrill said "IIRC, sound subsystem can producuce custom mapped compound pages". Link: http://lkml.kernel.org/r/c440d69879e34209feba21e12d236d06bc0a25db.1543577156.git.jstancek@redhat.com Fixes: e1534ae95004 ("mm: differentiate page_mapped() from page_mapcount() for compound pages") Signed-off-by: Jan Stancek <jstancek@redhat.com> Debugged-by: Laszlo Ersek <lersek@redhat.com> Suggested-by: "Kirill A. Shutemov" <kirill@shutemov.name> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Reviewed-by: David Hildenbrand <david@redhat.com> Reviewed-by: Andrea Arcangeli <aarcange@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | mm/memory.c: initialise mmu_notifier_range correctlyMatthew Wilcox2019-01-081-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | One of the paths in follow_pte_pmd() initialised the mmu_notifier_range incorrectly. Link: http://lkml.kernel.org/r/20190103002126.GM6310@bombadil.infradead.org Fixes: ac46d4f3c432 ("mm/mmu_notifier: use structure for invalidate_range_start/end calls v2") Signed-off-by: Matthew Wilcox <willy@infradead.org> Tested-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Jérôme Glisse <jglisse@redhat.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Jan Kara <jack@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>