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* mm/mmap.c: fix arithmetic overflow in __vm_enough_memory()Roman Gushchin2015-02-111-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | I noticed, that "allowed" can easily overflow by falling below 0, because (total_vm / 32) can be larger than "allowed". The problem occurs in OVERCOMMIT_NONE mode. In this case, a huge allocation can success and overcommit the system (despite OVERCOMMIT_NONE mode). All subsequent allocations will fall (system-wide), so system become unusable. The problem was masked out by commit c9b1d0981fcc ("mm: limit growth of 3% hardcoded other user reserve"), but it's easy to reproduce it on older kernels: 1) set overcommit_memory sysctl to 2 2) mmap() large file multiple times (with VM_SHARED flag) 3) try to malloc() large amount of memory It also can be reproduced on newer kernels, but miss-configured sysctl_user_reserve_kbytes is required. Fix this issue by switching to signed arithmetic here. [akpm@linux-foundation.org: use min_t] Signed-off-by: Roman Gushchin <klamm@yandex-team.ru> Cc: Andrew Shewmaker <agshew@gmail.com> Cc: Rik van Riel <riel@redhat.com> Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Reviewed-by: Michal Hocko <mhocko@suse.cz> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: fix false-positive warning on exit due mm_nr_pmds(mm)Kirill A. Shutemov2015-02-111-5/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The problem is that we check nr_ptes/nr_pmds in exit_mmap() which happens *before* pgd_free(). And if an arch does pte/pmd allocation in pgd_alloc() and frees them in pgd_free() we see offset in counters by the time of the checks. We tried to workaround this by offsetting expected counter value according to FIRST_USER_ADDRESS for both nr_pte and nr_pmd in exit_mmap(). But it doesn't work in some cases: 1. ARM with LPAE enabled also has non-zero USER_PGTABLES_CEILING, but upper addresses occupied with huge pmd entries, so the trick with offsetting expected counter value will get really ugly: we will have to apply it nr_pmds, but not nr_ptes. 2. Metag has non-zero FIRST_USER_ADDRESS, but doesn't do allocation pte/pmd page tables allocation in pgd_alloc(), just setup a pgd entry which is allocated at boot and shared accross all processes. The proposal is to move the check to check_mm() which happens *after* pgd_free() and do proper accounting during pgd_alloc() and pgd_free() which would bring counters to zero if nothing leaked. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Reported-by: Tyler Baker <tyler.baker@linaro.org> Tested-by: Tyler Baker <tyler.baker@linaro.org> Tested-by: Nishanth Menon <nm@ti.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: James Hogan <james.hogan@imgtec.com> Cc: Guan Xuetao <gxt@mprc.pku.edu.cn> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: account pmd page tables to the processKirill A. Shutemov2015-02-111-1/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Dave noticed that unprivileged process can allocate significant amount of memory -- >500 MiB on x86_64 -- and stay unnoticed by oom-killer and memory cgroup. The trick is to allocate a lot of PMD page tables. Linux kernel doesn't account PMD tables to the process, only PTE. The use-cases below use few tricks to allocate a lot of PMD page tables while keeping VmRSS and VmPTE low. oom_score for the process will be 0. #include <errno.h> #include <stdio.h> #include <stdlib.h> #include <unistd.h> #include <sys/mman.h> #include <sys/prctl.h> #define PUD_SIZE (1UL << 30) #define PMD_SIZE (1UL << 21) #define NR_PUD 130000 int main(void) { char *addr = NULL; unsigned long i; prctl(PR_SET_THP_DISABLE); for (i = 0; i < NR_PUD ; i++) { addr = mmap(addr + PUD_SIZE, PUD_SIZE, PROT_WRITE|PROT_READ, MAP_ANONYMOUS|MAP_PRIVATE, -1, 0); if (addr == MAP_FAILED) { perror("mmap"); break; } *addr = 'x'; munmap(addr, PMD_SIZE); mmap(addr, PMD_SIZE, PROT_WRITE|PROT_READ, MAP_ANONYMOUS|MAP_PRIVATE|MAP_FIXED, -1, 0); if (addr == MAP_FAILED) perror("re-mmap"), exit(1); } printf("PID %d consumed %lu KiB in PMD page tables\n", getpid(), i * 4096 >> 10); return pause(); } The patch addresses the issue by account PMD tables to the process the same way we account PTE. The main place where PMD tables is accounted is __pmd_alloc() and free_pmd_range(). But there're few corner cases: - HugeTLB can share PMD page tables. The patch handles by accounting the table to all processes who share it. - x86 PAE pre-allocates few PMD tables on fork. - Architectures with FIRST_USER_ADDRESS > 0. We need to adjust sanity check on exit(2). Accounting only happens on configuration where PMD page table's level is present (PMD is not folded). As with nr_ptes we use per-mm counter. The counter value is used to calculate baseline for badness score by oom-killer. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Reported-by: Dave Hansen <dave.hansen@linux.intel.com> Cc: Hugh Dickins <hughd@google.com> Reviewed-by: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Pavel Emelyanov <xemul@openvz.org> Cc: David Rientjes <rientjes@google.com> Tested-by: Sedat Dilek <sedat.dilek@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* rmap: drop support of non-linear mappingsKirill A. Shutemov2015-02-101-17/+7
| | | | | | | | | We don't create non-linear mappings anymore. Let's drop code which handles them in rmap. Signed-off-by: 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>
* mm: replace remap_file_pages() syscall with emulationKirill A. Shutemov2015-02-101-0/+69
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | remap_file_pages(2) was invented to be able efficiently map parts of huge file into limited 32-bit virtual address space such as in database workloads. Nonlinear mappings are pain to support and it seems there's no legitimate use-cases nowadays since 64-bit systems are widely available. Let's drop it and get rid of all these special-cased code. The patch replaces the syscall with emulation which creates new VMA on each remap_file_pages(), unless they it can be merged with an adjacent one. I didn't find *any* real code that uses remap_file_pages(2) to test emulation impact on. I've checked Debian code search and source of all packages in ALT Linux. No real users: libc wrappers, mentions in strace, gdb, valgrind and this kind of stuff. There are few basic tests in LTP for the syscall. They work just fine with emulation. To test performance impact, I've written small test case which demonstrate pretty much worst case scenario: map 4G shmfs file, write to begin of every page pgoff of the page, remap pages in reverse order, read every page. The test creates 1 million of VMAs if emulation is in use, so I had to set vm.max_map_count to 1100000 to avoid -ENOMEM. Before: 23.3 ( +- 4.31% ) seconds After: 43.9 ( +- 0.85% ) seconds Slowdown: 1.88x I believe we can live with that. Test case: #define _GNU_SOURCE #include <assert.h> #include <stdlib.h> #include <stdio.h> #include <sys/mman.h> #define MB (1024UL * 1024) #define SIZE (4096 * MB) int main(int argc, char **argv) { unsigned long *p; long i, pass; for (pass = 0; pass < 10; pass++) { p = mmap(NULL, SIZE, PROT_READ|PROT_WRITE, MAP_SHARED | MAP_ANONYMOUS, -1, 0); if (p == MAP_FAILED) { perror("mmap"); return -1; } for (i = 0; i < SIZE / 4096; i++) p[i * 4096 / sizeof(*p)] = i; for (i = 0; i < SIZE / 4096; i++) { if (remap_file_pages(p + i * 4096 / sizeof(*p), 4096, 0, (SIZE - 4096 * (i + 1)) >> 12, 0)) { perror("remap_file_pages"); return -1; } } for (i = SIZE / 4096 - 1; i >= 0; i--) assert(p[i * 4096 / sizeof(*p)] == SIZE / 4096 - i - 1); munmap(p, SIZE); } return 0; } [akpm@linux-foundation.org: fix spello] [sasha.levin@oracle.com: initialize populate before usage] [sasha.levin@oracle.com: grab file ref to prevent race while mmaping] Signed-off-by: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Dave Jones <davej@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Armin Rigo <arigo@tunes.org> Signed-off-by: Sasha Levin <sasha.levin@oracle.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: fix corner case in anon_vma endless growing preventionKonstantin Khlebnikov2015-01-111-2/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Fix for BUG_ON(anon_vma->degree) splashes in unlink_anon_vmas() ("kernel BUG at mm/rmap.c:399!") caused by commit 7a3ef208e662 ("mm: prevent endless growth of anon_vma hierarchy") Anon_vma_clone() is usually called for a copy of source vma in destination argument. If source vma has anon_vma it should be already in dst->anon_vma. NULL in dst->anon_vma is used as a sign that it's called from anon_vma_fork(). In this case anon_vma_clone() finds anon_vma for reusing. Vma_adjust() calls it differently and this breaks anon_vma reusing logic: anon_vma_clone() links vma to old anon_vma and updates degree counters but vma_adjust() overrides vma->anon_vma right after that. As a result final unlink_anon_vmas() decrements degree for wrong anon_vma. This patch assigns ->anon_vma before calling anon_vma_clone(). Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com> Reported-and-tested-by: Chris Clayton <chris2553@googlemail.com> Reported-and-tested-by: Oded Gabbay <oded.gabbay@amd.com> Reported-and-tested-by: Chih-Wei Huang <cwhuang@android-x86.org> Acked-by: Rik van Riel <riel@redhat.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Daniel Forrest <dan.forrest@ssec.wisc.edu> Cc: Michal Hocko <mhocko@suse.cz> Cc: stable@vger.kernel.org # to match back-porting of 7a3ef208e662 Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: Don't count the stack guard page towards RLIMIT_STACKLinus Torvalds2015-01-111-2/+5
| | | | | | | | | | | | | | | | | | | | | Commit fee7e49d4514 ("mm: propagate error from stack expansion even for guard page") made sure that we return the error properly for stack growth conditions. It also theorized that counting the guard page towards the stack limit might break something, but also said "Let's see if anybody notices". Somebody did notice. Apparently android-x86 sets the stack limit very close to the limit indeed, and including the guard page in the rlimit check causes the android 'zygote' process problems. So this adds the (fairly trivial) code to make the stack rlimit check be against the actual real stack size, rather than the size of the vma that includes the guard page. Reported-and-tested-by: Chih-Wei Huang <cwhuang@android-x86.org> Cc: Jay Foad <jay.foad@gmail.com> Cc: stable@kernel.org # to match back-porting of fee7e49d4514 Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: export find_extend_vma() and handle_mm_fault() for driver useJesse Barnes2014-12-131-0/+2
| | | | | | | | | | | This lets drivers like the AMD IOMMUv2 driver handle faults a bit more simply, rather than doing tricks with page refs and get_user_pages(). Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org> Cc: Oded Gabbay <oded.gabbay@amd.com> Cc: Joerg Roedel <jroedel@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: convert i_mmap_mutex to rwsemDavidlohr Bueso2014-12-131-4/+4
| | | | | | | | | | | | | | | | | | | | | | | | The i_mmap_mutex is a close cousin of the anon vma lock, both protecting similar data, one for file backed pages and the other for anon memory. To this end, this lock can also be a rwsem. In addition, there are some important opportunities to share the lock when there are no tree modifications. This conversion is straightforward. For now, all users take the write lock. [sfr@canb.auug.org.au: update fremap.c] Signed-off-by: Davidlohr Bueso <dbueso@suse.de> Reviewed-by: Rik van Riel <riel@redhat.com> Acked-by: "Kirill A. Shutemov" <kirill@shutemov.name> Acked-by: Hugh Dickins <hughd@google.com> Cc: Oleg Nesterov <oleg@redhat.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Acked-by: Mel Gorman <mgorman@suse.de> Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: use new helper functions around the i_mmap_mutexDavidlohr Bueso2014-12-131-7/+7
| | | | | | | | | | | | | | | | Convert all open coded mutex_lock/unlock calls to the i_mmap_[lock/unlock]_write() helpers. Signed-off-by: Davidlohr Bueso <dbueso@suse.de> Acked-by: Rik van Riel <riel@redhat.com> Acked-by: "Kirill A. Shutemov" <kirill@shutemov.name> Acked-by: Hugh Dickins <hughd@google.com> Cc: Oleg Nesterov <oleg@redhat.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Acked-by: Mel Gorman <mgorman@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge branch 'x86-mpx-for-linus' of ↵Linus Torvalds2014-12-101-0/+2
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 MPX support from Thomas Gleixner: "This enables support for x86 MPX. MPX is a new debug feature for bound checking in user space. It requires kernel support to handle the bound tables and decode the bound violating instruction in the trap handler" * 'x86-mpx-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: asm-generic: Remove asm-generic arch_bprm_mm_init() mm: Make arch_unmap()/bprm_mm_init() available to all architectures x86: Cleanly separate use of asm-generic/mm_hooks.h x86 mpx: Change return type of get_reg_offset() fs: Do not include mpx.h in exec.c x86, mpx: Add documentation on Intel MPX x86, mpx: Cleanup unused bound tables x86, mpx: On-demand kernel allocation of bounds tables x86, mpx: Decode MPX instruction to get bound violation information x86, mpx: Add MPX-specific mmap interface x86, mpx: Introduce VM_MPX to indicate that a VMA is MPX specific x86, mpx: Add MPX to disabled features ia64: Sync struct siginfo with general version mips: Sync struct siginfo with general version mpx: Extend siginfo structure to include bound violation information x86, mpx: Rename cfg_reg_u and status_reg x86: mpx: Give bndX registers actual names x86: Remove arbitrary instruction size limit in instruction decoder
| * x86, mpx: Cleanup unused bound tablesDave Hansen2014-11-181-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The previous patch allocates bounds tables on-demand. As noted in an earlier description, these can add up to *HUGE* amounts of memory. This has caused OOMs in practice when running tests. This patch adds support for freeing bounds tables when they are no longer in use. There are two types of mappings in play when unmapping tables: 1. The mapping with the actual data, which userspace is munmap()ing or brk()ing away, etc... 2. The mapping for the bounds table *backing* the data (is tagged with VM_MPX, see the patch "add MPX specific mmap interface"). If userspace use the prctl() indroduced earlier in this patchset to enable the management of bounds tables in kernel, when it unmaps the first type of mapping with the actual data, the kernel needs to free the mapping for the bounds table backing the data. This patch hooks in at the very end of do_unmap() to do so. We look at the addresses being unmapped and find the bounds directory entries and tables which cover those addresses. If an entire table is unused, we clear associated directory entry and free the table. Once we unmap the bounds table, we would have a bounds directory entry pointing at empty address space. That address space might now be allocated for some other (random) use, and the MPX hardware might now try to walk it as if it were a bounds table. That would be bad. So any unmapping of an enture bounds table has to be accompanied by a corresponding write to the bounds directory entry to invalidate it. That write to the bounds directory can fault, which causes the following problem: Since we are doing the freeing from munmap() (and other paths like it), we hold mmap_sem for write. If we fault, the page fault handler will attempt to acquire mmap_sem for read and we will deadlock. To avoid the deadlock, we pagefault_disable() when touching the bounds directory entry and use a get_user_pages() to resolve the fault. The unmapping of bounds tables happends under vm_munmap(). We also (indirectly) call vm_munmap() to _do_ the unmapping of the bounds tables. We avoid unbounded recursion by disallowing freeing of bounds tables *for* bounds tables. This would not occur normally, so should not have any practical impact. Being strict about it here helps ensure that we do not have an exploitable stack overflow. Based-on-patch-by: Qiaowei Ren <qiaowei.ren@intel.com> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Cc: linux-mm@kvack.org Cc: linux-mips@linux-mips.org Cc: Dave Hansen <dave@sr71.net> Link: http://lkml.kernel.org/r/20141114151831.E4531C4A@viggo.jf.intel.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* | mm: fix anon_vma_clone() error treatmentDaniel Forrest2014-12-031-3/+7
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Andrew Morton noticed that the error return from anon_vma_clone() was being dropped and replaced with -ENOMEM (which is not itself a bug because the only error return value from anon_vma_clone() is -ENOMEM). I did an audit of callers of anon_vma_clone() and discovered an actual bug where the error return was being lost. In __split_vma(), between Linux 3.11 and 3.12 the code was changed so the err variable is used before the call to anon_vma_clone() and the default initial value of -ENOMEM is overwritten. So a failure of anon_vma_clone() will return success since err at this point is now zero. Below is a patch which fixes this bug and also propagates the error return value from anon_vma_clone() in all cases. Fixes: ef0855d334e1 ("mm: mempolicy: turn vma_set_policy() into vma_dup_policy()") Signed-off-by: Daniel Forrest <dan.forrest@ssec.wisc.edu> Reviewed-by: Michal Hocko <mhocko@suse.cz> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Tim Hartrick <tim@edgecast.com> Cc: Hugh Dickins <hughd@google.com> Cc: Michel Lespinasse <walken@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: <stable@vger.kernel.org> [3.12+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm, thp: fix collapsing of hugepages on madviseDavid Rientjes2014-10-291-4/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | If an anonymous mapping is not allowed to fault thp memory and then madvise(MADV_HUGEPAGE) is used after fault, khugepaged will never collapse this memory into thp memory. This occurs because the madvise(2) handler for thp, hugepage_madvise(), clears VM_NOHUGEPAGE on the stack and it isn't stored in vma->vm_flags until the final action of madvise_behavior(). This causes the khugepaged_enter_vma_merge() to be a no-op in hugepage_madvise() when the vma had previously had VM_NOHUGEPAGE set. Fix this by passing the correct vma flags to the khugepaged mm slot handler. There's no chance khugepaged can run on this vma until after madvise_behavior() returns since we hold mm->mmap_sem. It would be possible to clear VM_NOHUGEPAGE directly from vma->vm_flags in hugepage_advise(), but I didn't want to introduce special case behavior into madvise_behavior(). I think it's best to just let it always set vma->vm_flags itself. Signed-off-by: David Rientjes <rientjes@google.com> Reported-by: Suleiman Souhlal <suleiman@google.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: 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: softdirty: enable write notifications on VMAs after VM_SOFTDIRTY clearedPeter Feiner2014-10-141-17/+28
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | For VMAs that don't want write notifications, PTEs created for read faults have their write bit set. If the read fault happens after VM_SOFTDIRTY is cleared, then the PTE's softdirty bit will remain clear after subsequent writes. Here's a simple code snippet to demonstrate the bug: char* m = mmap(NULL, getpagesize(), PROT_READ | PROT_WRITE, MAP_ANONYMOUS | MAP_SHARED, -1, 0); system("echo 4 > /proc/$PPID/clear_refs"); /* clear VM_SOFTDIRTY */ assert(*m == '\0'); /* new PTE allows write access */ assert(!soft_dirty(x)); *m = 'x'; /* should dirty the page */ assert(soft_dirty(x)); /* fails */ With this patch, write notifications are enabled when VM_SOFTDIRTY is cleared. Furthermore, to avoid unnecessary faults, write notifications are disabled when VM_SOFTDIRTY is set. As a side effect of enabling and disabling write notifications with care, this patch fixes a bug in mprotect where vm_page_prot bits set by drivers were zapped on mprotect. An analogous bug was fixed in mmap by commit c9d0bf241451 ("mm: uncached vma support with writenotify"). Signed-off-by: Peter Feiner <pfeiner@google.com> Reported-by: Peter Feiner <pfeiner@google.com> Suggested-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Pavel Emelyanov <xemul@parallels.com> Cc: Jamie Liu <jamieliu@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Bjorn Helgaas <bhelgaas@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge branch 'for-3.18' of ↵Linus Torvalds2014-10-101-1/+1
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu Pull percpu updates from Tejun Heo: "A lot of activities on percpu front. Notable changes are... - percpu allocator now can take @gfp. If @gfp doesn't contain GFP_KERNEL, it tries to allocate from what's already available to the allocator and a work item tries to keep the reserve around certain level so that these atomic allocations usually succeed. This will replace the ad-hoc percpu memory pool used by blk-throttle and also be used by the planned blkcg support for writeback IOs. Please note that I noticed a bug in how @gfp is interpreted while preparing this pull request and applied the fix 6ae833c7fe0c ("percpu: fix how @gfp is interpreted by the percpu allocator") just now. - percpu_ref now uses longs for percpu and global counters instead of ints. It leads to more sparse packing of the percpu counters on 64bit machines but the overhead should be negligible and this allows using percpu_ref for refcnting pages and in-memory objects directly. - The switching between percpu and single counter modes of a percpu_ref is made independent of putting the base ref and a percpu_ref can now optionally be initialized in single or killed mode. This allows avoiding percpu shutdown latency for cases where the refcounted objects may be synchronously created and destroyed in rapid succession with only a fraction of them reaching fully operational status (SCSI probing does this when combined with blk-mq support). It's also planned to be used to implement forced single mode to detect underflow more timely for debugging. There's a separate branch percpu/for-3.18-consistent-ops which cleans up the duplicate percpu accessors. That branch causes a number of conflicts with s390 and other trees. I'll send a separate pull request w/ resolutions once other branches are merged" * 'for-3.18' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu: (33 commits) percpu: fix how @gfp is interpreted by the percpu allocator blk-mq, percpu_ref: start q->mq_usage_counter in atomic mode percpu_ref: make INIT_ATOMIC and switch_to_atomic() sticky percpu_ref: add PERCPU_REF_INIT_* flags percpu_ref: decouple switching to percpu mode and reinit percpu_ref: decouple switching to atomic mode and killing percpu_ref: add PCPU_REF_DEAD percpu_ref: rename things to prepare for decoupling percpu/atomic mode switch percpu_ref: replace pcpu_ prefix with percpu_ percpu_ref: minor code and comment updates percpu_ref: relocate percpu_ref_reinit() Revert "blk-mq, percpu_ref: implement a kludge for SCSI blk-mq stall during probe" Revert "percpu: free percpu allocation info for uniprocessor system" percpu-refcount: make percpu_ref based on longs instead of ints percpu-refcount: improve WARN messages percpu: fix locking regression in the failure path of pcpu_alloc() percpu-refcount: add @gfp to percpu_ref_init() proportions: add @gfp to init functions percpu_counter: add @gfp to percpu_counter_init() percpu_counter: make percpu_counters_lock irq-safe ...
| * Merge branch 'for-linus' of ↵Tejun Heo2014-09-241-8/+8
| |\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-block into for-3.18 This is to receive 0a30288da1ae ("blk-mq, percpu_ref: implement a kludge for SCSI blk-mq stall during probe") which implements __percpu_ref_kill_expedited() to work around SCSI blk-mq stall. The commit reverted and patches to implement proper fix will be added. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Kent Overstreet <kmo@daterainc.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Christoph Hellwig <hch@lst.de>
| * | percpu_counter: add @gfp to percpu_counter_init()Tejun Heo2014-09-081-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Percpu allocator now supports allocation mask. Add @gfp to percpu_counter_init() so that !GFP_KERNEL allocation masks can be used with percpu_counters too. We could have left percpu_counter_init() alone and added percpu_counter_init_gfp(); however, the number of users isn't that high and introducing _gfp variants to all percpu data structures would be quite ugly, so let's just do the conversion. This is the one with the most users. Other percpu data structures are a lot easier to convert. This patch doesn't make any functional difference. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Jan Kara <jack@suse.cz> Acked-by: "David S. Miller" <davem@davemloft.net> Cc: x86@kernel.org Cc: Jens Axboe <axboe@kernel.dk> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Andrew Morton <akpm@linux-foundation.org>
* | | mm: use VM_BUG_ON_MM where possibleSasha Levin2014-10-091-3/+4
| | | | | | | | | | | | | | | | | | | | | | | | Dump the contents of the relevant struct_mm when we hit the bug condition. Signed-off-by: Sasha Levin <sasha.levin@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | | mm/mmap.c: clean up CONFIG_DEBUG_VM_RB checksAndrew Morton2014-10-091-6/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - be consistent in printing the test which failed - one message was actually wrong (a<b != b>a) - don't print second bogus warning if browse_rb() failed Cc: Sasha Levin <sasha.levin@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | | mm: convert a few VM_BUG_ON callers to VM_BUG_ON_VMASasha Levin2014-10-091-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Trivially convert a few VM_BUG_ON calls to VM_BUG_ON_VMA to extract more information when they trigger. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Sasha Levin <sasha.levin@oracle.com> Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Konstantin Khlebnikov <khlebnikov@openvz.org> Cc: Rik van Riel <riel@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Michal Hocko <mhocko@suse.cz> Cc: Hugh Dickins <hughd@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Michel Lespinasse <walken@google.com> Cc: Minchan Kim <minchan@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | | mm: use may_adjust_brk helperCyrill Gorcunov2014-10-091-4/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Kees Cook <keescook@chromium.org> Cc: Tejun Heo <tj@kernel.org> Cc: Andrew Vagin <avagin@openvz.org> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: H. Peter Anvin <hpa@zytor.com> Acked-by: Serge Hallyn <serge.hallyn@canonical.com> Cc: Pavel Emelyanov <xemul@parallels.com> Cc: Vasiliy Kulikov <segoon@openwall.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Michael Kerrisk <mtk.manpages@gmail.com> Cc: Julien Tinnes <jln@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | | mm/mmap.c: whitespace fixesvishnu.ps2014-10-091-18/+19
| |/ |/| | | | | | | | | Signed-off-by: vishnu.ps <vishnu.ps@samsung.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | mm/mmap.c: use pr_emerg when printing BUG related informationSasha Levin2014-09-101-8/+8
|/ | | | | | | | | | Make sure we actually see the output of validate_mm() and browse_rb() before triggering a BUG(). pr_info isn't shown by default so the reason for the BUG() isn't obvious. Signed-off-by: Sasha Levin <sasha.levin@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: allow drivers to prevent new writable mappingsDavid Herrmann2014-08-081-6/+24
| | | | | | | | | | | | | | | | | | | | | | | | | | | This patch (of 6): The i_mmap_writable field counts existing writable mappings of an address_space. To allow drivers to prevent new writable mappings, make this counter signed and prevent new writable mappings if it is negative. This is modelled after i_writecount and DENYWRITE. This will be required by the shmem-sealing infrastructure to prevent any new writable mappings after the WRITE seal has been set. In case there exists a writable mapping, this operation will fail with EBUSY. Note that we rely on the fact that iff you already own a writable mapping, you can increase the counter without using the helpers. This is the same that we do for i_writecount. Signed-off-by: David Herrmann <dh.herrmann@gmail.com> Acked-by: Hugh Dickins <hughd@google.com> Cc: Michael Kerrisk <mtk.manpages@gmail.com> Cc: Ryan Lortie <desrt@desrt.ca> Cc: Lennart Poettering <lennart@poettering.net> Cc: Daniel Mack <zonque@gmail.com> Cc: Andy Lutomirski <luto@amacapital.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: catch memory commitment underflowKonstantin Khlebnikov2014-08-061-0/+5
| | | | | | | | | | | | | | | Print a warning (if CONFIG_DEBUG_VM=y) when memory commitment becomes too negative. This shouldn't happen any more - the previous two patches fixed the committed_as underflow issues. [akpm@linux-foundation.org: use VM_WARN_ONCE, per Dave] Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Hugh Dickins <hughd@google.com> Cc: Dave Hansen <dave.hansen@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: convert some level-less printks to pr_*Mitchel Humpherys2014-06-061-9/+12
| | | | | | | | | | | | | | | | printk is meant to be used with an associated log level. There are some instances of printk scattered around the mm code where the log level is missing. Add a log level and adhere to suggestions by scripts/checkpatch.pl by moving to the pr_* macros. Also add the typical pr_fmt definition so that print statements can be easily traced back to the modules where they occur, correlated one with another, etc. This will require the removal of some (now redundant) prefixes on a few print statements. Signed-off-by: Mitchel Humpherys <mitchelh@codeaurora.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge branch 'x86/vdso' of ↵Linus Torvalds2014-06-051-29/+60
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip into next Pull x86 cdso updates from Peter Anvin: "Vdso cleanups and improvements largely from Andy Lutomirski. This makes the vdso a lot less ''special''" * 'x86/vdso' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/vdso, build: Make LE access macros clearer, host-safe x86/vdso, build: Fix cross-compilation from big-endian architectures x86/vdso, build: When vdso2c fails, unlink the output x86, vdso: Fix an OOPS accessing the HPET mapping w/o an HPET x86, mm: Replace arch_vma_name with vm_ops->name for vsyscalls x86, mm: Improve _install_special_mapping and fix x86 vdso naming mm, fs: Add vm_ops->name as an alternative to arch_vma_name x86, vdso: Fix an OOPS accessing the HPET mapping w/o an HPET x86, vdso: Remove vestiges of VDSO_PRELINK and some outdated comments x86, vdso: Move the vvar and hpet mappings next to the 64-bit vDSO x86, vdso: Move the 32-bit vdso special pages after the text x86, vdso: Reimplement vdso.so preparation in build-time C x86, vdso: Move syscall and sysenter setup into kernel/cpu/common.c x86, vdso: Clean up 32-bit vs 64-bit vdso params x86, mm: Ensure correct alignment of the fixmap
| * x86, mm: Improve _install_special_mapping and fix x86 vdso namingAndy Lutomirski2014-05-201-29/+60
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Using arch_vma_name to give special mappings a name is awkward. x86 currently implements it by comparing the start address of the vma to the expected address of the vdso. This requires tracking the start address of special mappings and is probably buggy if a special vma is split or moved. Improve _install_special_mapping to just name the vma directly. Use it to give the x86 vvar area a name, which should make CRIU's life easier. As a side effect, the vvar area will show up in core dumps. This could be considered weird and is fixable. [hpa: I say we accept this as-is but be prepared to deal with knocking out the vvars from core dumps if this becomes a problem.] Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Pavel Emelyanov <xemul@parallels.com> Signed-off-by: Andy Lutomirski <luto@amacapital.net> Link: http://lkml.kernel.org/r/276b39b6b645fb11e345457b503f17b83c2c6fd0.1400538962.git.luto@amacapital.net Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
* | mm/mmap.c: remove the first mapping checkHuang Shijie2014-06-041-3/+2
| | | | | | | | | | | | | | | | | | Remove the first mapping check for vma_link. Move the mutex_lock into the braces when vma->vm_file is true. Signed-off-by: Huang Shijie <b32955@freescale.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | mm/mmap.c: replace IS_ERR and PTR_ERR with PTR_ERR_OR_ZERODuan Jiong2014-06-041-3/+1
|/ | | | | | | | | | Fix a coccinelle error regarding usage of IS_ERR and PTR_ERR instead of PTR_ERR_OR_ZERO. Signed-off-by: Duan Jiong <duanj.fnst@cn.fujitsu.com> Acked-by: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: per-thread vma cachingDavidlohr Bueso2014-04-071-26/+29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch is a continuation of efforts trying to optimize find_vma(), avoiding potentially expensive rbtree walks to locate a vma upon faults. The original approach (https://lkml.org/lkml/2013/11/1/410), where the largest vma was also cached, ended up being too specific and random, thus further comparison with other approaches were needed. There are two things to consider when dealing with this, the cache hit rate and the latency of find_vma(). Improving the hit-rate does not necessarily translate in finding the vma any faster, as the overhead of any fancy caching schemes can be too high to consider. We currently cache the last used vma for the whole address space, which provides a nice optimization, reducing the total cycles in find_vma() by up to 250%, for workloads with good locality. On the other hand, this simple scheme is pretty much useless for workloads with poor locality. Analyzing ebizzy runs shows that, no matter how many threads are running, the mmap_cache hit rate is less than 2%, and in many situations below 1%. The proposed approach is to replace this scheme with a small per-thread cache, maximizing hit rates at a very low maintenance cost. Invalidations are performed by simply bumping up a 32-bit sequence number. The only expensive operation is in the rare case of a seq number overflow, where all caches that share the same address space are flushed. Upon a miss, the proposed replacement policy is based on the page number that contains the virtual address in question. Concretely, the following results are seen on an 80 core, 8 socket x86-64 box: 1) System bootup: Most programs are single threaded, so the per-thread scheme does improve ~50% hit rate by just adding a few more slots to the cache. +----------------+----------+------------------+ | caching scheme | hit-rate | cycles (billion) | +----------------+----------+------------------+ | baseline | 50.61% | 19.90 | | patched | 73.45% | 13.58 | +----------------+----------+------------------+ 2) Kernel build: This one is already pretty good with the current approach as we're dealing with good locality. +----------------+----------+------------------+ | caching scheme | hit-rate | cycles (billion) | +----------------+----------+------------------+ | baseline | 75.28% | 11.03 | | patched | 88.09% | 9.31 | +----------------+----------+------------------+ 3) Oracle 11g Data Mining (4k pages): Similar to the kernel build workload. +----------------+----------+------------------+ | caching scheme | hit-rate | cycles (billion) | +----------------+----------+------------------+ | baseline | 70.66% | 17.14 | | patched | 91.15% | 12.57 | +----------------+----------+------------------+ 4) Ebizzy: There's a fair amount of variation from run to run, but this approach always shows nearly perfect hit rates, while baseline is just about non-existent. The amounts of cycles can fluctuate between anywhere from ~60 to ~116 for the baseline scheme, but this approach reduces it considerably. For instance, with 80 threads: +----------------+----------+------------------+ | caching scheme | hit-rate | cycles (billion) | +----------------+----------+------------------+ | baseline | 1.06% | 91.54 | | patched | 99.97% | 14.18 | +----------------+----------+------------------+ [akpm@linux-foundation.org: fix nommu build, per Davidlohr] [akpm@linux-foundation.org: document vmacache_valid() logic] [akpm@linux-foundation.org: attempt to untangle header files] [akpm@linux-foundation.org: add vmacache_find() BUG_ON] [hughd@google.com: add vmacache_valid_mm() (from Oleg)] [akpm@linux-foundation.org: coding-style fixes] [akpm@linux-foundation.org: adjust and enhance comments] Signed-off-by: Davidlohr Bueso <davidlohr@hp.com> Reviewed-by: Rik van Riel <riel@redhat.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Reviewed-by: Michel Lespinasse <walken@google.com> Cc: Oleg Nesterov <oleg@redhat.com> Tested-by: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge branch 'locks-3.15' of git://git.samba.org/jlayton/linuxLinus Torvalds2014-04-041-1/+1
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull file locking updates from Jeff Layton: "Highlights: - maintainership change for fs/locks.c. Willy's not interested in maintaining it these days, and is OK with Bruce and I taking it. - fix for open vs setlease race that Al ID'ed - cleanup and consolidation of file locking code - eliminate unneeded BUG() call - merge of file-private lock implementation" * 'locks-3.15' of git://git.samba.org/jlayton/linux: locks: make locks_mandatory_area check for file-private locks locks: fix locks_mandatory_locked to respect file-private locks locks: require that flock->l_pid be set to 0 for file-private locks locks: add new fcntl cmd values for handling file private locks locks: skip deadlock detection on FL_FILE_PVT locks locks: pass the cmd value to fcntl_getlk/getlk64 locks: report l_pid as -1 for FL_FILE_PVT locks locks: make /proc/locks show IS_FILE_PVT locks as type "FLPVT" locks: rename locks_remove_flock to locks_remove_file locks: consolidate checks for compatible filp->f_mode values in setlk handlers locks: fix posix lock range overflow handling locks: eliminate BUG() call when there's an unexpected lock on file close locks: add __acquires and __releases annotations to locks_start and locks_stop locks: remove "inline" qualifier from fl_link manipulation functions locks: clean up comment typo locks: close potential race between setlease and open MAINTAINERS: update entry for fs/locks.c
| * locks: fix locks_mandatory_locked to respect file-private locksJeff Layton2014-03-311-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | As Trond pointed out, you can currently deadlock yourself by setting a file-private lock on a file that requires mandatory locking and then trying to do I/O on it. Avoid this problem by plumbing some knowledge of file-private locks into the mandatory locking code. In order to do this, we must pass down information about the struct file that's being used to locks_verify_locked. Reported-by: Trond Myklebust <trond.myklebust@primarydata.com> Signed-off-by: Jeff Layton <jlayton@redhat.com> Acked-by: J. Bruce Fields <bfields@redhat.com>
* | mm/mmap.c: mark function as staticRashika Kheria2014-04-031-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Mark function as static in mmap.c because they are not used outside this file. This eliminates the following warning in mm/mmap.c: mm/mmap.c:407:6: warning: no previous prototype for `validate_mm' [-Wmissing-prototypes] Signed-off-by: Rashika Kheria <rashika.kheria@gmail.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org> Reviewed-by: Rik van Riel <riel@redhat.com> Acked-by: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | mm: Add new func _install_special_mapping() to mmap.cStefani Seibold2014-03-181-4/+16
|/ | | | | | | | | | | | | | | The _install_special_mapping() is the new base function for install_special_mapping(). This function will return a pointer of the created VMA or a error code in an ERR_PTR() This new function will be needed by the for the vdso 32 bit support to map the additonal vvar and hpet pages into the 32 bit address space. This will be done with io_remap_pfn_range() and remap_pfn_range, which requieres a vm_area_struct. Reviewed-by: Andy Lutomirski <luto@amacapital.net> Signed-off-by: Stefani Seibold <stefani@seibold.net> Link: http://lkml.kernel.org/r/1395094933-14252-3-git-send-email-stefani@seibold.net Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
* mm: ignore VM_SOFTDIRTY on VMA mergingCyrill Gorcunov2014-01-231-2/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The VM_SOFTDIRTY bit affects vma merge routine: if two VMAs has all bits in vm_flags matched except dirty bit the kernel can't longer merge them and this forces the kernel to generate new VMAs instead. It finally may lead to the situation when userspace application reaches vm.max_map_count limit and get crashed in worse case | (gimp:11768): GLib-ERROR **: gmem.c:110: failed to allocate 4096 bytes | | (file-tiff-load:12038): LibGimpBase-WARNING **: file-tiff-load: gimp_wire_read(): error | xinit: connection to X server lost | | waiting for X server to shut down | /usr/lib64/gimp/2.0/plug-ins/file-tiff-load terminated: Hangup | /usr/lib64/gimp/2.0/plug-ins/script-fu terminated: Hangup | /usr/lib64/gimp/2.0/plug-ins/script-fu terminated: Hangup https://bugzilla.kernel.org/show_bug.cgi?id=67651 https://bugzilla.gnome.org/show_bug.cgi?id=719619#c0 Initial problem came from missed VM_SOFTDIRTY in do_brk() routine but even if we would set up VM_SOFTDIRTY here, there is still a way to prevent VMAs from merging: one can call | echo 4 > /proc/$PID/clear_refs and clear all VM_SOFTDIRTY over all VMAs presented in memory map, then new do_brk() will try to extend old VMA and finds that dirty bit doesn't match thus new VMA will be generated. As discussed with Pavel, the right approach should be to ignore VM_SOFTDIRTY bit when we're trying to merge VMAs and if merge successed we mark extended VMA with dirty bit where needed. Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org> Reported-by: Bastian Hougaard <gnome@rvzt.net> Reported-by: Mel Gorman <mgorman@suse.de> Cc: Pavel Emelyanov <xemul@parallels.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: audit/fix non-modular users of module_init in core codePaul Gortmaker2014-01-231-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Code that is obj-y (always built-in) or dependent on a bool Kconfig (built-in or absent) can never be modular. So using module_init as an alias for __initcall can be somewhat misleading. Fix these up now, so that we can relocate module_init from init.h into module.h in the future. If we don't do this, we'd have to add module.h to obviously non-modular code, and that would be a worse thing. The audit targets the following module_init users for change: mm/ksm.c bool KSM mm/mmap.c bool MMU mm/huge_memory.c bool TRANSPARENT_HUGEPAGE mm/mmu_notifier.c bool MMU_NOTIFIER Note that direct use of __initcall is discouraged, vs. one of the priority categorized subgroups. As __initcall gets mapped onto device_initcall, our use of subsys_initcall (which makes sense for these files) will thus change this registration from level 6-device to level 4-subsys (i.e. slightly earlier). However no observable impact of that difference has been observed during testing. One might think that core_initcall (l2) or postcore_initcall (l3) would be more appropriate for anything in mm/ but if we look at some actual init functions themselves, we see things like: mm/huge_memory.c --> hugepage_init --> hugepage_init_sysfs mm/mmap.c --> init_user_reserve --> sysctl_user_reserve_kbytes mm/ksm.c --> ksm_init --> sysfs_create_group and hence the choice of subsys_initcall (l4) seems reasonable, and at the same time minimizes the risk of changing the priority too drastically all at once. We can adjust further in the future. Also, several instances of missing ";" at EOL are fixed. Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/mmap.c: add mlock_future_check() helperDavidlohr Bueso2014-01-211-22/+23
| | | | | | | | | | | | | | Both do_brk and do_mmap_pgoff verify that we are actually capable of locking future pages if the corresponding VM_LOCKED flags are used. Encapsulate this logic into a single mlock_future_check() helper function. Signed-off-by: Davidlohr Bueso <davidlohr@hp.com> Cc: Rik van Riel <riel@redhat.com> Reviewed-by: Michel Lespinasse <walken@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: add overcommit_kbytes sysctl variableJerome Marchand2014-01-211-0/+1
| | | | | | | | | | | | | | | | | | | Some applications that run on HPC clusters are designed around the availability of RAM and the overcommit ratio is fine tuned to get the maximum usage of memory without swapping. With growing memory, the 1%-of-all-RAM grain provided by overcommit_ratio has become too coarse for these workload (on a 2TB machine it represents no less than 20GB). This patch adds the new overcommit_kbytes sysctl variable that allow a much finer grain. [akpm@linux-foundation.org: coding-style fixes] [akpm@linux-foundation.org: fix nommu build] Signed-off-by: Jerome Marchand <jmarchan@redhat.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: convert mm->nr_ptes to atomic_long_tKirill A. Shutemov2013-11-151-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | With split page table lock for PMD level we can't hold mm->page_table_lock while updating nr_ptes. Let's convert it to atomic_long_t to avoid races. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Tested-by: Alex Thorlton <athorlton@sgi.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: "Eric W . Biederman" <ebiederm@xmission.com> Cc: "Paul E . McKenney" <paulmck@linux.vnet.ibm.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Andi Kleen <ak@linux.intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Dave Jones <davej@redhat.com> Cc: David Howells <dhowells@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Kees Cook <keescook@chromium.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Michael Kerrisk <mtk.manpages@gmail.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: Robin Holt <robinmholt@gmail.com> Cc: Sedat Dilek <sedat.dilek@gmail.com> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge branch 'akpm' (patches from Andrew Morton)Linus Torvalds2013-11-131-9/+7
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Merge first patch-bomb from Andrew Morton: "Quite a lot of other stuff is banked up awaiting further next->mainline merging, but this batch contains: - Lots of random misc patches - OCFS2 - Most of MM - backlight updates - lib/ updates - printk updates - checkpatch updates - epoll tweaking - rtc updates - hfs - hfsplus - documentation - procfs - update gcov to gcc-4.7 format - IPC" * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (269 commits) ipc, msg: fix message length check for negative values ipc/util.c: remove unnecessary work pending test devpts: plug the memory leak in kill_sb ./Makefile: export initial ramdisk compression config option init/Kconfig: add option to disable kernel compression drivers: w1: make w1_slave::flags long to avoid memory corruption drivers/w1/masters/ds1wm.cuse dev_get_platdata() drivers/memstick/core/ms_block.c: fix unreachable state in h_msb_read_page() drivers/memstick/core/mspro_block.c: fix attributes array allocation drivers/pps/clients/pps-gpio.c: remove redundant of_match_ptr kernel/panic.c: reduce 1 byte usage for print tainted buffer gcov: reuse kbasename helper kernel/gcov/fs.c: use pr_warn() kernel/module.c: use pr_foo() gcov: compile specific gcov implementation based on gcc version gcov: add support for gcc 4.7 gcov format gcov: move gcov structs definitions to a gcc version specific file kernel/taskstats.c: return -ENOMEM when alloc memory fails in add_del_listener() kernel/taskstats.c: add nla_nest_cancel() for failure processing between nla_nest_start() and nla_nest_end() kernel/sysctl_binary.c: use scnprintf() instead of snprintf() ...
| * mm: factor commit limit calculationJerome Marchand2013-11-131-3/+1
| | | | | | | | | | | | | | | | | | | | | | | | The same calculation is currently done in three differents places. Factor that code so future changes has to be made at only one place. [akpm@linux-foundation.org: uninline vm_commit_limit()] Signed-off-by: Jerome Marchand <jmarchan@redhat.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Michal Hocko <mhocko@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * mm: ensure get_unmapped_area() returns higher address than mmap_min_addrAkira Takeuchi2013-11-131-5/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch fixes the problem that get_unmapped_area() can return illegal address and result in failing mmap(2) etc. In case that the address higher than PAGE_SIZE is set to /proc/sys/vm/mmap_min_addr, the address lower than mmap_min_addr can be returned by get_unmapped_area(), even if you do not pass any virtual address hint (i.e. the second argument). This is because the current get_unmapped_area() code does not take into account mmap_min_addr. This leads to two actual problems as follows: 1. mmap(2) can fail with EPERM on the process without CAP_SYS_RAWIO, although any illegal parameter is not passed. 2. The bottom-up search path after the top-down search might not work in arch_get_unmapped_area_topdown(). Note: The first and third chunk of my patch, which changes "len" check, are for more precise check using mmap_min_addr, and not for solving the above problem. [How to reproduce] --- test.c ------------------------------------------------- #include <stdio.h> #include <unistd.h> #include <sys/mman.h> #include <sys/errno.h> int main(int argc, char *argv[]) { void *ret = NULL, *last_map; size_t pagesize = sysconf(_SC_PAGESIZE); do { last_map = ret; ret = mmap(0, pagesize, PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0); // printf("ret=%p\n", ret); } while (ret != MAP_FAILED); if (errno != ENOMEM) { printf("ERR: unexpected errno: %d (last map=%p)\n", errno, last_map); } return 0; } --------------------------------------------------------------- $ gcc -m32 -o test test.c $ sudo sysctl -w vm.mmap_min_addr=65536 vm.mmap_min_addr = 65536 $ ./test (run as non-priviledge user) ERR: unexpected errno: 1 (last map=0x10000) Signed-off-by: Akira Takeuchi <takeuchi.akr@jp.panasonic.com> Signed-off-by: Kiyoshi Owada <owada.kiyoshi@jp.panasonic.com> Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * mmap: arch_get_unmapped_area(): use proper mmap base for bottom up directionHeiko Carstens2013-11-131-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This is more or less the generic variant of commit 41aacc1eea64 ("x86 get_unmapped_area: Access mmap_legacy_base through mm_struct member"). So effectively architectures which use an own arch_pick_mmap_layout() implementation but call the generic arch_get_unmapped_area() now can also randomize their mmap_base. All architectures which have an own arch_pick_mmap_layout() and call the generic arch_get_unmapped_area() (arm64, s390, tile) currently set mmap_base to TASK_UNMAPPED_BASE. This is also true for the generic arch_pick_mmap_layout() function. So this change is a no-op currently. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Radu Caragea <sinaelgl@gmail.com> Cc: Michel Lespinasse <walken@google.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Chris Metcalf <cmetcalf@tilera.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>
* | file->f_op is never NULL...Al Viro2013-10-241-2/+2
|/ | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* mm/mmap: remove unnecessary assignmentYanchuan Nian2013-09-111-1/+0
| | | | | | | | | | pgoff is not used after the statement "pgoff = vma->vm_pgoff;", so the assignment is redundant. Signed-off-by: Yanchuan Nian <ycnian@gmail.com> Acked-by: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: track vma changes with VM_SOFTDIRTY bitCyrill Gorcunov2013-09-111-1/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pavel reported that in case if vma area get unmapped and then mapped (or expanded) in-place, the soft dirty tracker won't be able to recognize this situation since it works on pte level and ptes are get zapped on unmap, loosing soft dirty bit of course. So to resolve this situation we need to track actions on vma level, there VM_SOFTDIRTY flag comes in. When new vma area created (or old expanded) we set this bit, and keep it here until application calls for clearing soft dirty bit. Thus when user space application track memory changes now it can detect if vma area is renewed. Reported-by: Pavel Emelyanov <xemul@parallels.com> Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Matt Mackall <mpm@selenic.com> Cc: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: KOSAKI Motohiro <kosaki.motohiro@gmail.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Peter Zijlstra <peterz@infradead.org> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> Cc: Rob Landley <rob@landley.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: mmap_region: kill correct_wcount/inode, use allow_write_access()Oleg Nesterov2013-09-111-9/+5
| | | | | | | | | | | | | | | | | | | | | correct_wcount and inode in mmap_region() just complicate the code. This boolean was needed previously, when deny_write_access() was called before vma_merge(), now we can simply check VM_DENYWRITE and do allow_write_access() if it is set. allow_write_access() checks file != NULL, so this is safe even if it was possible to use VM_DENYWRITE && !file. Just we need to ensure we use the same file which was deny_write_access()'ed, so the patch also moves "file = vma->vm_file" down after allow_write_access(). Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Colin Cross <ccross@android.com> Cc: David Rientjes <rientjes@google.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: do_mmap_pgoff: cleanup the usage of file_inode()Oleg Nesterov2013-09-111-3/+2
| | | | | | | | | | | | | | Simple cleanup. Move "struct inode *inode" variable into "if (file)" block to simplify the code and avoid the unnecessary check. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Colin Cross <ccross@android.com> Cc: David Rientjes <rientjes@google.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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