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2015-09-22mm, dax: VMA with vm_ops->pfn_mkwrite wants to be write-notifiedKirill A. Shutemov
For VM_PFNMAP and VM_MIXEDMAP we use vm_ops->pfn_mkwrite instead of vm_ops->page_mkwrite to notify abort write access. This means we want vma->vm_page_prot to be write-protected if the VMA provides this vm_ops. A theoretical scenario that will cause these missed events is: On writable mapping with vm_ops->pfn_mkwrite, but without vm_ops->page_mkwrite: read fault followed by write access to the pfn. Writable pte will be set up on read fault and write fault will not be generated. I found it examining Dave's complaint on generic/080: http://lkml.kernel.org/g/20150831233803.GO3902@dastard Although I don't think it's the reason. It shouldn't be a problem for ext2/ext4 as they provide both pfn_mkwrite and page_mkwrite. [akpm@linux-foundation.org: add local vm_ops to avoid 80-cols mess] Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Yigal Korman <yigal@plexistor.com> Acked-by: Boaz Harrosh <boaz@plexistor.com> Cc: Matthew Wilcox <matthew.r.wilcox@intel.com> Cc: Jan Kara <jack@suse.cz> Cc: Dave Chinner <david@fromorbit.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-17revert "mm: make sure all file VMAs have ->vm_ops set"Andrew Morton
Revert commit 6dc296e7df4c "mm: make sure all file VMAs have ->vm_ops set". Will Deacon reports that it "causes some mmap regressions in LTP, which appears to use a MAP_PRIVATE mmap of /dev/zero as a way to get anonymous pages in some of its tests (specifically mmap10 [1])". William Shuman reports Oracle crashes. So revert the patch while we work out what to do. Reported-by: William Shuman <wshuman3@gmail.com> Reported-by: Will Deacon <will.deacon@arm.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-10mm: make sure all file VMAs have ->vm_ops setKirill A. Shutemov
We rely on vma->vm_ops == NULL to detect anonymous VMA: see vma_is_anonymous(), but some drivers doesn't set ->vm_ops. As a result we can end up with anonymous page in private file mapping. That should not lead to serious misbehaviour, but nevertheless is wrong. Let's fix by setting up dummy ->vm_ops for file mmapping if f_op->mmap() didn't set its own. The patch also adds sanity check into __vma_link_rb(). It will help catch broken VMAs which inserted directly into mm_struct via insert_vm_struct(). Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Reviewed-by: Oleg Nesterov <oleg@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Minchan Kim <minchan@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-10mm, mpx: add "vm_flags_t vm_flags" arg to do_mmap_pgoff()Oleg Nesterov
Add the additional "vm_flags_t vm_flags" argument to do_mmap_pgoff(), rename it to do_mmap(), and re-introduce do_mmap_pgoff() as a simple wrapper on top of do_mmap(). Perhaps we should update the callers of do_mmap_pgoff() and kill it later. This way mpx_mmap() can simply call do_mmap(vm_flags => VM_MPX) and do not play with vm internals. After this change mmap_region() has a single user outside of mmap.c, arch/tile/mm/elf.c:arch_setup_additional_pages(). It would be nice to change arch/tile/ and unexport mmap_region(). [kirill@shutemov.name: fix build] [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Dave Hansen <dave.hansen@linux.intel.com> Tested-by: Dave Hansen <dave.hansen@linux.intel.com> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Ingo Molnar <mingo@elte.hu> Cc: Minchan Kim <minchan@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-08mm/mmap.c:insert_vm_struct(): check for failure before setting valuesChen Gang
There's no point in initializing vma->vm_pgoff if the insertion attempt will be failing anyway. Run the checks before performing the initialization. Signed-off-by: Chen Gang <gang.chen.5i5j@gmail.com> Cc: Michal Hocko <mhocko@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-08mm/mmap.c: simplify the failure return working flowChen Gang
__split_vma() doesn't need out_err label, neither need initializing err. copy_vma() can return NULL directly when kmem_cache_alloc() fails. Signed-off-by: Chen Gang <gang.chen.5i5j@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-08mremap: fix the wrong !vma->vm_file check in copy_vma()Oleg Nesterov
Test-case: #define _GNU_SOURCE #include <stdio.h> #include <unistd.h> #include <stdlib.h> #include <string.h> #include <sys/mman.h> #include <assert.h> void *find_vdso_vaddr(void) { FILE *perl; char buf[32] = {}; perl = popen("perl -e 'open STDIN,qq|/proc/@{[getppid]}/maps|;" "/^(.*?)-.*vdso/ && print hex $1 while <>'", "r"); fread(buf, sizeof(buf), 1, perl); fclose(perl); return (void *)atol(buf); } #define PAGE_SIZE 4096 void *get_unmapped_area(void) { void *p = mmap(0, PAGE_SIZE, PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS, -1,0); assert(p != MAP_FAILED); munmap(p, PAGE_SIZE); return p; } char save[2][PAGE_SIZE]; int main(void) { void *vdso = find_vdso_vaddr(); void *page[2]; assert(vdso); memcpy(save, vdso, sizeof (save)); // force another fault on the next check assert(madvise(vdso, 2 * PAGE_SIZE, MADV_DONTNEED) == 0); page[0] = mremap(vdso, PAGE_SIZE, PAGE_SIZE, MREMAP_FIXED | MREMAP_MAYMOVE, get_unmapped_area()); page[1] = mremap(vdso + PAGE_SIZE, PAGE_SIZE, PAGE_SIZE, MREMAP_FIXED | MREMAP_MAYMOVE, get_unmapped_area()); assert(page[0] != MAP_FAILED && page[1] != MAP_FAILED); printf("match: %d %d\n", !memcmp(save[0], page[0], PAGE_SIZE), !memcmp(save[1], page[1], PAGE_SIZE)); return 0; } fails without this patch. Before the previous commit it gets the wrong page, now it segfaults (which is imho better). This is because copy_vma() wrongly assumes that if vma->vm_file == NULL is irrelevant until the first fault which will use do_anonymous_page(). This is obviously wrong for the special mapping. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Hugh Dickins <hughd@google.com> Cc: Pavel Emelyanov <xemul@parallels.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-08mmap: fix the usage of ->vm_pgoff in special_mapping pathsOleg Nesterov
Test-case: #include <stdio.h> #include <unistd.h> #include <stdlib.h> #include <string.h> #include <sys/mman.h> #include <assert.h> void *find_vdso_vaddr(void) { FILE *perl; char buf[32] = {}; perl = popen("perl -e 'open STDIN,qq|/proc/@{[getppid]}/maps|;" "/^(.*?)-.*vdso/ && print hex $1 while <>'", "r"); fread(buf, sizeof(buf), 1, perl); fclose(perl); return (void *)atol(buf); } #define PAGE_SIZE 4096 int main(void) { void *vdso = find_vdso_vaddr(); assert(vdso); // of course they should differ, and they do so far printf("vdso pages differ: %d\n", !!memcmp(vdso, vdso + PAGE_SIZE, PAGE_SIZE)); // split into 2 vma's assert(mprotect(vdso, PAGE_SIZE, PROT_READ) == 0); // force another fault on the next check assert(madvise(vdso, 2 * PAGE_SIZE, MADV_DONTNEED) == 0); // now they no longer differ, the 2nd vm_pgoff is wrong printf("vdso pages differ: %d\n", !!memcmp(vdso, vdso + PAGE_SIZE, PAGE_SIZE)); return 0; } Output: vdso pages differ: 1 vdso pages differ: 0 This is because split_vma() correctly updates ->vm_pgoff, but the logic in insert_vm_struct() and special_mapping_fault() is absolutely broken, so the fault at vdso + PAGE_SIZE return the 1st page. The same happens if you simply unmap the 1st page. special_mapping_fault() does: pgoff = vmf->pgoff - vma->vm_pgoff; and this is _only_ correct if vma->vm_start mmaps the first page from ->vm_private_data array. vdso or any other user of install_special_mapping() is not anonymous, it has the "backing storage" even if it is just the array of pages. So we actually need to make vm_pgoff work as an offset in this array. Note: this also allows to fix another problem: currently gdb can't access "[vvar]" memory because in this case special_mapping_fault() doesn't work. Now that we can use ->vm_pgoff we can implement ->access() and fix this. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Hugh Dickins <hughd@google.com> Cc: Pavel Emelyanov <xemul@parallels.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-04userfaultfd: teach vma_merge to merge across vma->vm_userfaultfd_ctxAndrea Arcangeli
vma->vm_userfaultfd_ctx is yet another vma parameter that vma_merge must be aware about so that we can merge vmas back like they were originally before arming the userfaultfd on some memory range. Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Acked-by: Pavel Emelyanov <xemul@parallels.com> Cc: Sanidhya Kashyap <sanidhya.gatech@gmail.com> Cc: zhang.zhanghailiang@huawei.com Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Andres Lagar-Cavilla <andreslc@google.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Hugh Dickins <hughd@google.com> Cc: Peter Feiner <pfeiner@google.com> Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: "Huangpeng (Peter)" <peter.huangpeng@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-07-10vfs: Commit to never having exectuables on proc and sysfs.Eric W. Biederman
Today proc and sysfs do not contain any executable files. Several applications today mount proc or sysfs without noexec and nosuid and then depend on there being no exectuables files on proc or sysfs. Having any executable files show on proc or sysfs would cause a user space visible regression, and most likely security problems. Therefore commit to never allowing executables on proc and sysfs by adding a new flag to mark them as filesystems without executables and enforce that flag. Test the flag where MNT_NOEXEC is tested today, so that the only user visible effect will be that exectuables will be treated as if the execute bit is cleared. The filesystems proc and sysfs do not currently incoporate any executable files so this does not result in any user visible effects. This makes it unnecessary to vet changes to proc and sysfs tightly for adding exectuable files or changes to chattr that would modify existing files, as no matter what the individual file say they will not be treated as exectuable files by the vfs. Not having to vet changes to closely is important as without this we are only one proc_create call (or another goof up in the implementation of notify_change) from having problematic executables on proc. Those mistakes are all too easy to make and would create a situation where there are security issues or the assumptions of some program having to be broken (and cause userspace regressions). Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2015-06-24mm/mmap.c: optimization of do_mmap_pgoff functionPiotr Kwapulinski
The simple check for zero length memory mapping may be performed earlier. So that in case of zero length memory mapping some unnecessary code is not executed at all. It does not make the code less readable and saves some CPU cycles. Signed-off-by: Piotr Kwapulinski <kwapulinski.piotr@gmail.com> Acked-by: Michal Hocko <mhocko@suse.cz> 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>
2015-04-15mm/mmap.c: use while instead of if+gotoRasmus Villemoes
The creators of the C language gave us the while keyword. Let's use that instead of synthesizing it from if+goto. Made possible by 6597d783397a ("mm/mmap.c: replace find_vma_prepare() with clearer find_vma_links()"). [akpm@linux-foundation.org: fix 80-col overflows] Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Sasha Levin <sasha.levin@oracle.com> Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Roman Gushchin <klamm@yandex-team.ru> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-15mm: remove rest of ACCESS_ONCE() usagesJason Low
We converted some of the usages of ACCESS_ONCE to READ_ONCE in the mm/ tree since it doesn't work reliably on non-scalar types. This patch removes the rest of the usages of ACCESS_ONCE, and use the new READ_ONCE API for the read accesses. This makes things cleaner, instead of using separate/multiple sets of APIs. Signed-off-by: Jason Low <jason.low2@hp.com> Acked-by: Michal Hocko <mhocko@suse.cz> Acked-by: Davidlohr Bueso <dave@stgolabs.net> Acked-by: Rik van Riel <riel@redhat.com> Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-14mm: rename __mlock_vma_pages_range() to populate_vma_page_range()Kirill A. Shutemov
__mlock_vma_pages_range() doesn't necessarily mlock pages. It depends on vma flags. The same codepath is used for MAP_POPULATE. Let's rename __mlock_vma_pages_range() to populate_vma_page_range(). This patch also drops mlock_vma_pages_range() references from documentation. It has gone in cea10a19b797 ("mm: directly use __mlock_vma_pages_range() in find_extend_vma()"). Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: David Rientjes <rientjes@google.com> Cc: Michel Lespinasse <walken@google.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-03-25mm: fix anon_vma->degree underflow in anon_vma endless growing preventionLeon Yu
I have constantly stumbled upon "kernel BUG at mm/rmap.c:399!" after upgrading to 3.19 and had no luck with 4.0-rc1 neither. So, after looking into new logic introduced by commit 7a3ef208e662 ("mm: prevent endless growth of anon_vma hierarchy"), I found chances are that unlink_anon_vmas() is called without incrementing dst->anon_vma->degree in anon_vma_clone() due to allocation failure. If dst->anon_vma is not NULL in error path, its degree will be incorrectly decremented in unlink_anon_vmas() and eventually underflow when exiting as a result of another call to unlink_anon_vmas(). That's how "kernel BUG at mm/rmap.c:399!" is triggered for me. This patch fixes the underflow by dropping dst->anon_vma when allocation fails. It's safe to do so regardless of original value of dst->anon_vma because dst->anon_vma doesn't have valid meaning if anon_vma_clone() fails. Besides, callers don't care dst->anon_vma in such case neither. Also suggested by Michal Hocko, we can clean up vma_adjust() a bit as anon_vma_clone() now does the work. [akpm@linux-foundation.org: tweak comment] Fixes: 7a3ef208e662 ("mm: prevent endless growth of anon_vma hierarchy") Signed-off-by: Leon Yu <chianglungyu@gmail.com> Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com> Reviewed-by: Michal Hocko <mhocko@suse.cz> Acked-by: Rik van Riel <riel@redhat.com> Acked-by: David Rientjes <rientjes@google.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-02-11mm/mmap.c: fix arithmetic overflow in __vm_enough_memory()Roman Gushchin
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>
2015-02-11mm: fix false-positive warning on exit due mm_nr_pmds(mm)Kirill A. Shutemov
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>
2015-02-11mm: account pmd page tables to the processKirill A. Shutemov
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>
2015-02-10rmap: drop support of non-linear mappingsKirill A. Shutemov
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>
2015-02-10mm: replace remap_file_pages() syscall with emulationKirill A. Shutemov
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>
2015-01-11mm: fix corner case in anon_vma endless growing preventionKonstantin Khlebnikov
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>
2015-01-11mm: Don't count the stack guard page towards RLIMIT_STACKLinus Torvalds
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>
2014-12-13mm: export find_extend_vma() and handle_mm_fault() for driver useJesse Barnes
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>
2014-12-13mm: convert i_mmap_mutex to rwsemDavidlohr Bueso
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>
2014-12-13mm: use new helper functions around the i_mmap_mutexDavidlohr Bueso
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>
2014-12-10Merge branch 'x86-mpx-for-linus' of ↵Linus Torvalds
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
2014-12-03mm: fix anon_vma_clone() error treatmentDaniel Forrest
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>
2014-11-18x86, mpx: Cleanup unused bound tablesDave Hansen
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>
2014-10-29mm, thp: fix collapsing of hugepages on madviseDavid Rientjes
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>
2014-10-14mm: softdirty: enable write notifications on VMAs after VM_SOFTDIRTY clearedPeter Feiner
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>
2014-10-10Merge branch 'for-3.18' of ↵Linus Torvalds
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 ...
2014-10-09mm: use VM_BUG_ON_MM where possibleSasha Levin
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>
2014-10-09mm/mmap.c: clean up CONFIG_DEBUG_VM_RB checksAndrew Morton
- 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>
2014-10-09mm: convert a few VM_BUG_ON callers to VM_BUG_ON_VMASasha Levin
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>
2014-10-09mm: use may_adjust_brk helperCyrill Gorcunov
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>
2014-10-09mm/mmap.c: whitespace fixesvishnu.ps
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>
2014-09-24Merge branch 'for-linus' of ↵Tejun Heo
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>
2014-09-10mm/mmap.c: use pr_emerg when printing BUG related informationSasha Levin
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>
2014-09-08percpu_counter: add @gfp to percpu_counter_init()Tejun Heo
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>
2014-08-08mm: allow drivers to prevent new writable mappingsDavid Herrmann
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>
2014-08-06mm: catch memory commitment underflowKonstantin Khlebnikov
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>
2014-06-06mm: convert some level-less printks to pr_*Mitchel Humpherys
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>
2014-06-05Merge branch 'x86/vdso' of ↵Linus Torvalds
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
2014-06-04mm/mmap.c: remove the first mapping checkHuang Shijie
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>
2014-06-04mm/mmap.c: replace IS_ERR and PTR_ERR with PTR_ERR_OR_ZERODuan Jiong
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>
2014-05-20x86, mm: Improve _install_special_mapping and fix x86 vdso namingAndy Lutomirski
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>
2014-04-07mm: per-thread vma cachingDavidlohr Bueso
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>
2014-04-04Merge branch 'locks-3.15' of git://git.samba.org/jlayton/linuxLinus Torvalds
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
2014-04-03mm/mmap.c: mark function as staticRashika Kheria
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>
2014-03-31locks: fix locks_mandatory_locked to respect file-private locksJeff Layton
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>