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2017-04-13zsmalloc: expand class bitMinchan Kim1-1/+1
Now 64K page system, zsamlloc has 257 classes so 8 class bit is not enough. With that, it corrupts the system when zsmalloc stores 65536byte data(ie, index number 256) so that this patch increases class bit for simple fix for stable backport. We should clean up this mess soon. index size 0 32 1 288 .. .. 204 52256 256 65536 Fixes: 3783689a1 ("zsmalloc: introduce zspage structure") Link: http://lkml.kernel.org/r/1492042622-12074-3-git-send-email-minchan@kernel.org Signed-off-by: Minchan Kim <minchan@kernel.org> Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-04-13thp: fix MADV_DONTNEED vs. MADV_FREE raceKirill A. Shutemov1-2/+1
Both MADV_DONTNEED and MADV_FREE handled with down_read(mmap_sem). It's critical to not clear pmd intermittently while handling MADV_FREE to avoid race with MADV_DONTNEED: CPU0: CPU1: madvise_free_huge_pmd() pmdp_huge_get_and_clear_full() madvise_dontneed() zap_pmd_range() pmd_trans_huge(*pmd) == 0 (without ptl) // skip the pmd set_pmd_at(); // pmd is re-established It results in MADV_DONTNEED skipping the pmd, leaving it not cleared. It violates MADV_DONTNEED interface and can result is userspace misbehaviour. Basically it's the same race as with numa balancing in change_huge_pmd(), but a bit simpler to mitigate: we don't need to preserve dirty/young flags here due to MADV_FREE functionality. [kirill.shutemov@linux.intel.com: Urgh... Power is special again] Link: http://lkml.kernel.org/r/20170303102636.bhd2zhtpds4mt62a@black.fi.intel.com Link: http://lkml.kernel.org/r/20170302151034.27829-4-kirill.shutemov@linux.intel.com Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Minchan Kim <minchan@kernel.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hillf Danton <hillf.zj@alibaba-inc.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-04-13thp: fix MADV_DONTNEED vs. numa balancing raceKirill A. Shutemov1-1/+33
In case prot_numa, we are under down_read(mmap_sem). It's critical to not clear pmd intermittently to avoid race with MADV_DONTNEED which is also under down_read(mmap_sem): CPU0: CPU1: change_huge_pmd(prot_numa=1) pmdp_huge_get_and_clear_notify() madvise_dontneed() zap_pmd_range() pmd_trans_huge(*pmd) == 0 (without ptl) // skip the pmd set_pmd_at(); // pmd is re-established The race makes MADV_DONTNEED miss the huge pmd and don't clear it which may break userspace. Found by code analysis, never saw triggered. Link: http://lkml.kernel.org/r/20170302151034.27829-3-kirill.shutemov@linux.intel.com Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hillf Danton <hillf.zj@alibaba-inc.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-04-13thp: reduce indentation level in change_huge_pmd()Kirill A. Shutemov1-26/+26
Patch series "thp: fix few MADV_DONTNEED races" For MADV_DONTNEED to work properly with huge pages, it's critical to not clear pmd intermittently unless you hold down_write(mmap_sem). Otherwise MADV_DONTNEED can miss the THP which can lead to userspace breakage. See example of such race in commit message of patch 2/4. All these races are found by code inspection. I haven't seen them triggered. I don't think it's worth to apply them to stable@. This patch (of 4): Restructure code in preparation for a fix. Link: http://lkml.kernel.org/r/20170302151034.27829-2-kirill.shutemov@linux.intel.com Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hillf Danton <hillf.zj@alibaba-inc.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-04-13z3fold: fix page locking in z3fold_alloc()Vitaly Wool1-2/+7
Stress testing of the current z3fold implementation on a 8-core system revealed it was possible that a z3fold page deleted from its unbuddied list in z3fold_alloc() would be put on another unbuddied list by z3fold_free() while z3fold_alloc() is still processing it. This has been introduced with commit 5a27aa822 ("z3fold: add kref refcounting") due to the removal of special handling of a z3fold page not on any list in z3fold_free(). To fix this, the z3fold page lock should be taken in z3fold_alloc() before the pool lock is released. To avoid deadlocking, we just try to lock the page as soon as we get a hold of it, and if trylock fails, we drop this page and take the next one. Signed-off-by: Vitaly Wool <vitalywool@gmail.com> Cc: Dan Streetman <ddstreet@ieee.org> Cc: <Oleksiy.Avramchenko@sony.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-04-08mm/mempolicy.c: fix error handling in set_mempolicy and mbind.Chris Salls1-12/+8
In the case that compat_get_bitmap fails we do not want to copy the bitmap to the user as it will contain uninitialized stack data and leak sensitive data. Signed-off-by: Chris Salls <salls@cs.ucsb.edu> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-04-08mm: move pcp and lru-pcp draining into single wqMichal Hocko4-26/+32
We currently have 2 specific WQ_RECLAIM workqueues in the mm code. vmstat_wq for updating pcp stats and lru_add_drain_wq dedicated to drain per cpu lru caches. This seems more than necessary because both can run on a single WQ. Both do not block on locks requiring a memory allocation nor perform any allocations themselves. We will save one rescuer thread this way. On the other hand drain_all_pages() queues work on the system wq which doesn't have rescuer and so this depend on memory allocation (when all workers are stuck allocating and new ones cannot be created). Initially we thought this would be more of a theoretical problem but Hugh Dickins has reported: : 4.11-rc has been giving me hangs after hours of swapping load. At : first they looked like memory leaks ("fork: Cannot allocate memory"); : but for no good reason I happened to do "cat /proc/sys/vm/stat_refresh" : before looking at /proc/meminfo one time, and the stat_refresh stuck : in D state, waiting for completion of flush_work like many kworkers. : kthreadd waiting for completion of flush_work in drain_all_pages(). This worker should be using WQ_RECLAIM as well in order to guarantee a forward progress. We can reuse the same one as for lru draining and vmstat. Link: http://lkml.kernel.org/r/20170307131751.24936-1-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Suggested-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Mel Gorman <mgorman@suse.de> Tested-by: Yang Li <pku.leo@gmail.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>
2017-04-08mm, swap_cgroup: reschedule when neeed in swap_cgroup_swapoff()David Rientjes1-0/+2
We got need_resched() warnings in swap_cgroup_swapoff() because swap_cgroup_ctrl[type].length is particularly large. Reschedule when needed. Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1704061315270.80559@chino.kir.corp.google.com Signed-off-by: David Rientjes <rientjes@google.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-04-08mm, thp: fix setting of defer+madvise thp defrag modeDavid Rientjes1-6/+6
Setting thp defrag mode of "defer+madvise" actually sets "defer" in the kernel due to the name similarity and the out-of-order way the string is checked in defrag_store(). Check the string in the correct order so that TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG is set appropriately for "defer+madvise". Fixes: 21440d7eb904 ("mm, thp: add new defer+madvise defrag option") Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1704051814420.137626@chino.kir.corp.google.com Signed-off-by: David Rientjes <rientjes@google.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-04-08mm/page_alloc.c: fix print order in show_free_areas()Alexander Polakov1-1/+1
Fixes: 11fb998986a72a ("mm: move most file-based accounting to the node") Link: http://lkml.kernel.org/r/1490377730.30219.2.camel@beget.ru Signed-off-by: Alexander Polyakov <apolyakov@beget.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: <stable@vger.kernel.org> [4.8+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-04-08mm: fix page_vma_mapped_walk() for ksm pagesHugh Dickins1-7/+8
Doug Smythies reports oops with KSM in this backtrace, I've been seeing the same: page_vma_mapped_walk+0xe6/0x5b0 page_referenced_one+0x91/0x1a0 rmap_walk_ksm+0x100/0x190 rmap_walk+0x4f/0x60 page_referenced+0x149/0x170 shrink_active_list+0x1c2/0x430 shrink_node_memcg+0x67a/0x7a0 shrink_node+0xe1/0x320 kswapd+0x34b/0x720 Just as observed in commit 4b0ece6fa016 ("mm: migrate: fix remove_migration_pte() for ksm pages"), you cannot use page->index calculations on ksm pages. page_vma_mapped_walk() is relying on __vma_address(), where a ksm page can lead it off the end of the page table, and into whatever nonsense is in the next page, ending as an oops inside check_pte()'s pte_page(). KSM tells page_vma_mapped_walk() exactly where to look for the page, it does not need any page->index calculation: and that's so also for all the normal and file and anon pages - just not for THPs and their subpages. Get out early in most cases: instead of a PageKsm test, move down the earlier not-THP-page test, as suggested by Kirill. I'm also slightly worried that this loop can stray into other vmas, so added a vm_end test to prevent surprises; though I have not imagined anything worse than a very contrived case, in which a page mlocked in the next vma might be reclaimed because it is not mlocked in this vma. Fixes: ace71a19cec5 ("mm: introduce page_vma_mapped_walk()") Link: http://lkml.kernel.org/r/alpine.LSU.2.11.1704031104400.1118@eggly.anvils Signed-off-by: Hugh Dickins <hughd@google.com> Reported-by: Doug Smythies <dsmythies@telus.net> Tested-by: Doug Smythies <dsmythies@telus.net> Reviewed-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>
2017-03-31mm/hugetlb.c: don't call region_abort if region_chg failsMike Kravetz1-1/+3
Changes to hugetlbfs reservation maps is a two step process. The first step is a call to region_chg to determine what needs to be changed, and prepare that change. This should be followed by a call to call to region_add to commit the change, or region_abort to abort the change. The error path in hugetlb_reserve_pages called region_abort after a failed call to region_chg. As a result, the adds_in_progress counter in the reservation map is off by 1. This is caught by a VM_BUG_ON in resv_map_release when the reservation map is freed. syzkaller fuzzer (when using an injected kmalloc failure) found this bug, that resulted in the following: kernel BUG at mm/hugetlb.c:742! Call Trace: hugetlbfs_evict_inode+0x7b/0xa0 fs/hugetlbfs/inode.c:493 evict+0x481/0x920 fs/inode.c:553 iput_final fs/inode.c:1515 [inline] iput+0x62b/0xa20 fs/inode.c:1542 hugetlb_file_setup+0x593/0x9f0 fs/hugetlbfs/inode.c:1306 newseg+0x422/0xd30 ipc/shm.c:575 ipcget_new ipc/util.c:285 [inline] ipcget+0x21e/0x580 ipc/util.c:639 SYSC_shmget ipc/shm.c:673 [inline] SyS_shmget+0x158/0x230 ipc/shm.c:657 entry_SYSCALL_64_fastpath+0x1f/0xc2 RIP: resv_map_release+0x265/0x330 mm/hugetlb.c:742 Link: http://lkml.kernel.org/r/1490821682-23228-1-git-send-email-mike.kravetz@oracle.com Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com> Reported-by: Dmitry Vyukov <dvyukov@google.com> Acked-by: Hillf Danton <hillf.zj@alibaba-inc.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-03-31kasan: report only the first error by defaultMark Rutland2-5/+36
Disable kasan after the first report. There are several reasons for this: - Single bug quite often has multiple invalid memory accesses causing storm in the dmesg. - Write OOB access might corrupt metadata so the next report will print bogus alloc/free stacktraces. - Reports after the first easily could be not bugs by itself but just side effects of the first one. Given that multiple reports usually only do harm, it makes sense to disable kasan after the first one. If user wants to see all the reports, the boot-time parameter kasan_multi_shot must be used. [aryabinin@virtuozzo.com: wrote changelog and doc, added missing include] Link: http://lkml.kernel.org/r/20170323154416.30257-1-aryabinin@virtuozzo.com Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Andrey Konovalov <andreyknvl@google.com> Cc: Alexander Potapenko <glider@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-03-31mm: fix section name for .data..ro_after_initKees Cook1-1/+1
A section name for .data..ro_after_init was added by both: commit d07a980c1b8d ("s390: add proper __ro_after_init support") and commit d7c19b066dcf ("mm: kmemleak: scan .data.ro_after_init") The latter adds incorrect wrapping around the existing s390 section, and came later. I'd prefer the s390 naming, so this moves the s390-specific name up to the asm-generic/sections.h and renames the section as used by kmemleak (and in the future, kernel/extable.c). Link: http://lkml.kernel.org/r/20170327192213.GA129375@beast Signed-off-by: Kees Cook <keescook@chromium.org> Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com> [s390 parts] Acked-by: Jakub Kicinski <jakub.kicinski@netronome.com> Cc: Eddie Kovsky <ewk@edkovsky.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-03-31mm, hugetlb: use pte_present() instead of pmd_present() in follow_huge_pmd()Naoya Horiguchi1-2/+4
I found the race condition which triggers the following bug when move_pages() and soft offline are called on a single hugetlb page concurrently. Soft offlining page 0x119400 at 0x700000000000 BUG: unable to handle kernel paging request at ffffea0011943820 IP: follow_huge_pmd+0x143/0x190 PGD 7ffd2067 PUD 7ffd1067 PMD 0 [61163.582052] Oops: 0000 [#1] SMP Modules linked in: binfmt_misc ppdev virtio_balloon parport_pc pcspkr i2c_piix4 parport i2c_core acpi_cpufreq ip_tables xfs libcrc32c ata_generic pata_acpi virtio_blk 8139too crc32c_intel ata_piix serio_raw libata virtio_pci 8139cp virtio_ring virtio mii floppy dm_mirror dm_region_hash dm_log dm_mod [last unloaded: cap_check] CPU: 0 PID: 22573 Comm: iterate_numa_mo Tainted: P OE 4.11.0-rc2-mm1+ #2 Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011 RIP: 0010:follow_huge_pmd+0x143/0x190 RSP: 0018:ffffc90004bdbcd0 EFLAGS: 00010202 RAX: 0000000465003e80 RBX: ffffea0004e34d30 RCX: 00003ffffffff000 RDX: 0000000011943800 RSI: 0000000000080001 RDI: 0000000465003e80 RBP: ffffc90004bdbd18 R08: 0000000000000000 R09: ffff880138d34000 R10: ffffea0004650000 R11: 0000000000c363b0 R12: ffffea0011943800 R13: ffff8801b8d34000 R14: ffffea0000000000 R15: 000077ff80000000 FS: 00007fc977710740(0000) GS:ffff88007dc00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffea0011943820 CR3: 000000007a746000 CR4: 00000000001406f0 Call Trace: follow_page_mask+0x270/0x550 SYSC_move_pages+0x4ea/0x8f0 SyS_move_pages+0xe/0x10 do_syscall_64+0x67/0x180 entry_SYSCALL64_slow_path+0x25/0x25 RIP: 0033:0x7fc976e03949 RSP: 002b:00007ffe72221d88 EFLAGS: 00000246 ORIG_RAX: 0000000000000117 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fc976e03949 RDX: 0000000000c22390 RSI: 0000000000001400 RDI: 0000000000005827 RBP: 00007ffe72221e00 R08: 0000000000c2c3a0 R09: 0000000000000004 R10: 0000000000c363b0 R11: 0000000000000246 R12: 0000000000400650 R13: 00007ffe72221ee0 R14: 0000000000000000 R15: 0000000000000000 Code: 81 e4 ff ff 1f 00 48 21 c2 49 c1 ec 0c 48 c1 ea 0c 4c 01 e2 49 bc 00 00 00 00 00 ea ff ff 48 c1 e2 06 49 01 d4 f6 45 bc 04 74 90 <49> 8b 7c 24 20 40 f6 c7 01 75 2b 4c 89 e7 8b 47 1c 85 c0 7e 2a RIP: follow_huge_pmd+0x143/0x190 RSP: ffffc90004bdbcd0 CR2: ffffea0011943820 ---[ end trace e4f81353a2d23232 ]--- Kernel panic - not syncing: Fatal exception Kernel Offset: disabled This bug is triggered when pmd_present() returns true for non-present hugetlb, so fixing the present check in follow_huge_pmd() prevents it. Using pmd_present() to determine present/non-present for hugetlb is not correct, because pmd_present() checks multiple bits (not only _PAGE_PRESENT) for historical reason and it can misjudge hugetlb state. Fixes: e66f17ff7177 ("mm/hugetlb: take page table lock in follow_huge_pmd()") Link: http://lkml.kernel.org/r/1490149898-20231-1-git-send-email-n-horiguchi@ah.jp.nec.com Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Acked-by: Hillf Danton <hillf.zj@alibaba-inc.com> Cc: Hugh Dickins <hughd@google.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Gerald Schaefer <gerald.schaefer@de.ibm.com> Cc: <stable@vger.kernel.org> [4.0+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-03-31mm: workingset: fix premature shadow node shrinking with cgroupsJohannes Weiner1-1/+1
Commit 0a6b76dd23fa ("mm: workingset: make shadow node shrinker memcg aware") enabled cgroup-awareness in the shadow node shrinker, but forgot to also enable cgroup-awareness in the list_lru the shadow nodes sit on. Consequently, all shadow nodes are sitting on a global (per-NUMA node) list, while the shrinker applies the limits according to the amount of cache in the cgroup its shrinking. The result is excessive pressure on the shadow nodes from cgroups that have very little cache. Enable memcg-mode on the shadow node LRUs, such that per-cgroup limits are applied to per-cgroup lists. Fixes: 0a6b76dd23fa ("mm: workingset: make shadow node shrinker memcg aware") Link: http://lkml.kernel.org/r/20170322005320.8165-1-hannes@cmpxchg.org Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Vladimir Davydov <vdavydov@tarantool.org> Cc: Michal Hocko <mhocko@suse.com> Cc: <stable@vger.kernel.org> [4.6+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-03-31mm: rmap: fix huge file mmap accounting in the memcg statsJohannes Weiner1-2/+2
Huge pages are accounted as single units in the memcg's "file_mapped" counter. Account the correct number of base pages, like we do in the corresponding node counter. Link: http://lkml.kernel.org/r/20170322005111.3156-1-hannes@cmpxchg.org Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Cc: <stable@vger.kernel.org> [4.8+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-03-31mm: move mm_percpu_wq initialization earlierMichal Hocko1-3/+1
Yang Li has reported that drain_all_pages triggers a WARN_ON which means that this function is called earlier than the mm_percpu_wq is initialized on arm64 with CMA configured: WARNING: CPU: 2 PID: 1 at mm/page_alloc.c:2423 drain_all_pages+0x244/0x25c Modules linked in: CPU: 2 PID: 1 Comm: swapper/0 Not tainted 4.11.0-rc1-next-20170310-00027-g64dfbc5 #127 Hardware name: Freescale Layerscape 2088A RDB Board (DT) task: ffffffc07c4a6d00 task.stack: ffffffc07c4a8000 PC is at drain_all_pages+0x244/0x25c LR is at start_isolate_page_range+0x14c/0x1f0 [...] drain_all_pages+0x244/0x25c start_isolate_page_range+0x14c/0x1f0 alloc_contig_range+0xec/0x354 cma_alloc+0x100/0x1fc dma_alloc_from_contiguous+0x3c/0x44 atomic_pool_init+0x7c/0x208 arm64_dma_init+0x44/0x4c do_one_initcall+0x38/0x128 kernel_init_freeable+0x1a0/0x240 kernel_init+0x10/0xfc ret_from_fork+0x10/0x20 Fix this by moving the whole setup_vmstat which is an initcall right now to init_mm_internals which will be called right after the WQ subsystem is initialized. Link: http://lkml.kernel.org/r/20170315164021.28532-1-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Reported-by: Yang Li <pku.leo@gmail.com> Tested-by: Yang Li <pku.leo@gmail.com> Tested-by: Xiaolong Ye <xiaolong.ye@intel.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-03-31mm: migrate: fix remove_migration_pte() for ksm pagesNaoya Horiguchi1-2/+5
I found that calling page migration for ksm pages causes the following bug: page:ffffea0004d51180 count:2 mapcount:2 mapping:ffff88013c785141 index:0x913 flags: 0x57ffffc0040068(uptodate|lru|active|swapbacked) raw: 0057ffffc0040068 ffff88013c785141 0000000000000913 0000000200000001 raw: ffffea0004d5f9e0 ffffea0004d53f60 0000000000000000 ffff88007d81b800 page dumped because: VM_BUG_ON_PAGE(!PageLocked(page)) page->mem_cgroup:ffff88007d81b800 ------------[ cut here ]------------ kernel BUG at /src/linux-dev/mm/rmap.c:1086! invalid opcode: 0000 [#1] SMP Modules linked in: ppdev parport_pc virtio_balloon i2c_piix4 pcspkr parport i2c_core acpi_cpufreq ip_tables xfs libcrc32c ata_generic pata_acpi ata_piix 8139too libata virtio_blk 8139cp crc32c_intel mii virtio_pci virtio_ring serio_raw virtio floppy dm_mirror dm_region_hash dm_log dm_mod CPU: 0 PID: 3162 Comm: bash Not tainted 4.11.0-rc2-mm1+ #1 Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011 RIP: 0010:do_page_add_anon_rmap+0x1ba/0x260 RSP: 0018:ffffc90002473b30 EFLAGS: 00010282 RAX: 0000000000000021 RBX: ffffea0004d51180 RCX: 0000000000000006 RDX: 0000000000000000 RSI: 0000000000000082 RDI: ffff88007dc0dfe0 RBP: ffffc90002473b58 R08: 00000000fffffffe R09: 00000000000001c1 R10: 0000000000000005 R11: 00000000000001c0 R12: ffff880139ab3d80 R13: 0000000000000000 R14: 0000700000000200 R15: 0000160000000000 FS: 00007f5195f50740(0000) GS:ffff88007dc00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fd450287000 CR3: 000000007a08e000 CR4: 00000000001406f0 Call Trace: page_add_anon_rmap+0x18/0x20 remove_migration_pte+0x220/0x2c0 rmap_walk_ksm+0x143/0x220 rmap_walk+0x55/0x60 remove_migration_ptes+0x53/0x80 migrate_pages+0x8ed/0xb60 soft_offline_page+0x309/0x8d0 store_soft_offline_page+0xaf/0xf0 dev_attr_store+0x18/0x30 sysfs_kf_write+0x3a/0x50 kernfs_fop_write+0xff/0x180 __vfs_write+0x37/0x160 vfs_write+0xb2/0x1b0 SyS_write+0x55/0xc0 do_syscall_64+0x67/0x180 entry_SYSCALL64_slow_path+0x25/0x25 RIP: 0033:0x7f51956339e0 RSP: 002b:00007ffcfa0dffc8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 000000000000000c RCX: 00007f51956339e0 RDX: 000000000000000c RSI: 00007f5195f53000 RDI: 0000000000000001 RBP: 00007f5195f53000 R08: 000000000000000a R09: 00007f5195f50740 R10: 000000000000000b R11: 0000000000000246 R12: 00007f5195907400 R13: 000000000000000c R14: 0000000000000001 R15: 0000000000000000 Code: fe ff ff 48 81 c2 00 02 00 00 48 89 55 d8 e8 2e c3 fd ff 48 8b 55 d8 e9 42 ff ff ff 48 c7 c6 e0 52 a1 81 48 89 df e8 46 ad fe ff <0f> 0b 48 83 e8 01 e9 7f fe ff ff 48 83 e8 01 e9 96 fe ff ff 48 RIP: do_page_add_anon_rmap+0x1ba/0x260 RSP: ffffc90002473b30 ---[ end trace a679d00f4af2df48 ]--- Kernel panic - not syncing: Fatal exception Kernel Offset: disabled ---[ end Kernel panic - not syncing: Fatal exception The problem is in the following lines: new = page - pvmw.page->index + linear_page_index(vma, pvmw.address); The 'new' is calculated with 'page' which is given by the caller as a destination page and some offset adjustment for thp. But this doesn't properly work for ksm pages because pvmw.page->index doesn't change for each address but linear_page_index() changes, which means that 'new' points to different pages for each addresses backed by the ksm page. As a result, we try to set totally unrelated pages as destination pages, and that causes kernel crash. This patch fixes the miscalculation and makes ksm page migration work fine. Fixes: 3fe87967c536 ("mm: convert remove_migration_pte() to use page_vma_mapped_walk()") Link: http://lkml.kernel.org/r/1489717683-29905-1-git-send-email-n-horiguchi@ah.jp.nec.com Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Hillf Danton <hillf.zj@alibaba-inc.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-03-21mm, swap: Remove WARN_ON_ONCE() in free_swap_slot()Huang Ying1-2/+0
Before commit 452b94b8c8c7 ("mm/swap: don't BUG_ON() due to uninitialized swap slot cache"), the following bug is reported, ------------[ cut here ]------------ kernel BUG at mm/swap_slots.c:270! invalid opcode: 0000 [#1] SMP CPU: 5 PID: 1745 Comm: (sd-pam) Not tainted 4.11.0-rc1-00243-g24c534bb161b #1 Hardware name: System manufacturer System Product Name/Z170-K, BIOS 1803 05/06/2016 RIP: 0010:free_swap_slot+0xba/0xd0 Call Trace: swap_free+0x36/0x40 do_swap_page+0x360/0x6d0 __handle_mm_fault+0x880/0x1080 handle_mm_fault+0xd0/0x240 __do_page_fault+0x232/0x4d0 do_page_fault+0x20/0x70 page_fault+0x22/0x30 ---[ end trace aefc9ede53e0ab21 ]--- This is raised by the BUG_ON(!swap_slot_cache_initialized) in free_swap_slot(). This is incorrect, because even if the swap slots cache fails to be initialized, the swap should operate properly without the swap slots cache. And the use_swap_slot_cache check later in the function will protect the uninitialized swap slots cache case. In commit 452b94b8c8c7, the BUG_ON() is replaced by WARN_ON_ONCE(). In the patch, the WARN_ON_ONCE() is removed too. Reported-by: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Tim Chen <tim.c.chen@linux.intel.com> Cc: Michal Hocko <mhocko@suse.com> Signed-off-by: "Huang, Ying" <ying.huang@intel.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-03-19mm/swap: don't BUG_ON() due to uninitialized swap slot cacheLinus Torvalds1-1/+1
This BUG_ON() triggered for me once at shutdown, and I don't see a reason for the check. The code correctly checks whether the swap slot cache is usable or not, so an uninitialized swap slot cache is not actually problematic afaik. I've temporarily just switched the BUG_ON() to a WARN_ON_ONCE(), since I'm not sure why that seemingly pointless check was there. I suspect the real fix is to just remove it entirely, but for now we'll warn about it but not bring the machine down. Cc: "Huang, Ying" <ying.huang@intel.com> Cc: Tim Chen <tim.c.chen@linux.intel.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-03-16mm: add private lock to serialize memory hotplug operationsHeiko Carstens1-1/+5
Commit bfc8c90139eb ("mem-hotplug: implement get/put_online_mems") introduced new functions get/put_online_mems() and mem_hotplug_begin/end() in order to allow similar semantics for memory hotplug like for cpu hotplug. The corresponding functions for cpu hotplug are get/put_online_cpus() and cpu_hotplug_begin/done() for cpu hotplug. The commit however missed to introduce functions that would serialize memory hotplug operations like they are done for cpu hotplug with cpu_maps_update_begin/done(). This basically leaves mem_hotplug.active_writer unprotected and allows concurrent writers to modify it, which may lead to problems as outlined by commit f931ab479dd2 ("mm: fix devm_memremap_pages crash, use mem_hotplug_{begin, done}"). That commit was extended again with commit b5d24fda9c3d ("mm, devm_memremap_pages: hold device_hotplug lock over mem_hotplug_{begin, done}") which serializes memory hotplug operations for some call sites by using the device_hotplug lock. In addition with commit 3fc21924100b ("mm: validate device_hotplug is held for memory hotplug") a sanity check was added to mem_hotplug_begin() to verify that the device_hotplug lock is held. This in turn triggers the following warning on s390: WARNING: CPU: 6 PID: 1 at drivers/base/core.c:643 assert_held_device_hotplug+0x4a/0x58 Call Trace: assert_held_device_hotplug+0x40/0x58) mem_hotplug_begin+0x34/0xc8 add_memory_resource+0x7e/0x1f8 add_memory+0xda/0x130 add_memory_merged+0x15c/0x178 sclp_detect_standby_memory+0x2ae/0x2f8 do_one_initcall+0xa2/0x150 kernel_init_freeable+0x228/0x2d8 kernel_init+0x2a/0x140 kernel_thread_starter+0x6/0xc One possible fix would be to add more lock_device_hotplug() and unlock_device_hotplug() calls around each call site of mem_hotplug_begin/end(). But that would give the device_hotplug lock additional semantics it better should not have (serialize memory hotplug operations). Instead add a new memory_add_remove_lock which has the similar semantics like cpu_add_remove_lock for cpu hotplug. To keep things hopefully a bit easier the lock will be locked and unlocked within the mem_hotplug_begin/end() functions. Link: http://lkml.kernel.org/r/20170314125226.16779-2-heiko.carstens@de.ibm.com Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Reported-by: Sebastian Ott <sebott@linux.vnet.ibm.com> Acked-by: Dan Williams <dan.j.williams@intel.com> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Cc: Ben Hutchings <ben@decadent.org.uk> Cc: Gerald Schaefer <gerald.schaefer@de.ibm.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-03-16mm: don't warn when vmalloc() fails due to a fatal signalDmitry Vyukov1-1/+2
When vmalloc() fails it prints a very lengthy message with all the details about memory consumption assuming that it happened due to OOM. However, vmalloc() can also fail due to fatal signal pending. In such case the message is quite confusing because it suggests that it is OOM but the numbers suggest otherwise. The messages can also pollute console considerably. Don't warn when vmalloc() fails due to fatal signal pending. Link: http://lkml.kernel.org/r/20170313114425.72724-1-dvyukov@google.com Signed-off-by: Dmitry Vyukov <dvyukov@google.com> Reviewed-by: Matthew Wilcox <mawilcox@microsoft.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-03-16z3fold: fix spinlock unlocking in page reclaimVitaly Wool1-0/+1
Commmit 5a27aa822029 ("z3fold: add kref refcounting") introduced a bug in z3fold_reclaim_page() with function exit that may leave pool->lock spinlock held. Here comes the trivial fix. Fixes: 5a27aa822029 ("z3fold: add kref refcounting") Link: http://lkml.kernel.org/r/20170311222239.7b83d8e7ef1914e05497649f@gmail.com Reported-by: Alexey Khoroshilov <khoroshilov@ispras.ru> Signed-off-by: Vitaly Wool <vitalywool@gmail.com> Cc: Dan Streetman <ddstreet@ieee.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-03-14Merge branch 'for-4.11-fixes' of ↵Linus Torvalds2-5/+7
git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu Pull percpu fixes from Tejun Heo: - the allocation path was updating pcpu_nr_empty_pop_pages without the required locking which can lead to incorrect handling of empty chunks (e.g. keeping too many around), which is buggy but shouldn't lead to critical failures. Fixed by adding the locking - a trivial patch to drop an unused param from pcpu_get_pages() * 'for-4.11-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu: percpu: remove unused chunk_alloc parameter from pcpu_get_pages() percpu: acquire pcpu_lock when updating pcpu_nr_empty_pop_pages
2017-03-13mm, gup: fix typo in gup_p4d_range()Kirill A. Shutemov1-1/+1
gup_p4d_range() should call gup_pud_range(), not itself. [ This was not noticed on x86: this is the HAVE_GENERIC_RCU_GUP code used by arm[64] and powerpc - Linus ] Fixes: c2febafc6773 ("mm: convert generic code to 5-level paging") Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Reported-by: Chris Packham <chris.packham@alliedtelesis.co.nz> Reported-by: Anton Blanchard <anton@samba.org> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-03-10Merge branch 'prep-for-5level'Linus Torvalds16-104/+495
Merge 5-level page table prep from Kirill Shutemov: "Here's relatively low-risk part of 5-level paging patchset. Merging it now will make x86 5-level paging enabling in v4.12 easier. The first patch is actually x86-specific: detect 5-level paging support. It boils down to single define. The rest of patchset converts Linux MMU abstraction from 4- to 5-level paging. Enabling of new abstraction in most cases requires adding single line of code in arch-specific code. The rest is taken care by asm-generic/. Changes to mm/ code are mostly mechanical: add support for new page table level -- p4d_t -- where we deal with pud_t now. v2: - fix build on microblaze (Michal); - comment for __ARCH_HAS_5LEVEL_HACK in kasan_populate_zero_shadow(); - acks from Michal" * emailed patches from Kirill A Shutemov <kirill.shutemov@linux.intel.com>: mm: introduce __p4d_alloc() mm: convert generic code to 5-level paging asm-generic: introduce <asm-generic/pgtable-nop4d.h> arch, mm: convert all architectures to use 5level-fixup.h asm-generic: introduce __ARCH_USE_5LEVEL_HACK asm-generic: introduce 5level-fixup.h x86/cpufeature: Add 5-level paging detection
2017-03-10Merge branch 'akpm' (patches from Andrew)Linus Torvalds8-28/+117
Merge fixes from Andrew Morton: "26 fixes" * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (26 commits) userfaultfd: remove wrong comment from userfaultfd_ctx_get() fat: fix using uninitialized fields of fat_inode/fsinfo_inode sh: cayman: IDE support fix kasan: fix races in quarantine_remove_cache() kasan: resched in quarantine_remove_cache() mm: do not call mem_cgroup_free() from within mem_cgroup_alloc() thp: fix another corner case of munlock() vs. THPs rmap: fix NULL-pointer dereference on THP munlocking mm/memblock.c: fix memblock_next_valid_pfn() userfaultfd: selftest: vm: allow to build in vm/ directory userfaultfd: non-cooperative: userfaultfd_remove revalidate vma in MADV_DONTNEED userfaultfd: non-cooperative: fix fork fctx->new memleak mm/cgroup: avoid panic when init with low memory drivers/md/bcache/util.h: remove duplicate inclusion of blkdev.h mm/vmstats: add thp_split_pud event for clarity include/linux/fs.h: fix unsigned enum warning with gcc-4.2 userfaultfd: non-cooperative: release all ctx in dup_userfaultfd_complete userfaultfd: non-cooperative: robustness check userfaultfd: non-cooperative: rollback userfaultfd_exit x86, mm: unify exit paths in gup_pte_range() ...
2017-03-09kasan: fix races in quarantine_remove_cache()Dmitry Vyukov1-6/+36
quarantine_remove_cache() frees all pending objects that belong to the cache, before we destroy the cache itself. However there are currently two possibilities how it can fail to do so. First, another thread can hold some of the objects from the cache in temp list in quarantine_put(). quarantine_put() has a windows of enabled interrupts, and on_each_cpu() in quarantine_remove_cache() can finish right in that window. These objects will be later freed into the destroyed cache. Then, quarantine_reduce() has the same problem. It grabs a batch of objects from the global quarantine, then unlocks quarantine_lock and then frees the batch. quarantine_remove_cache() can finish while some objects from the cache are still in the local to_free list in quarantine_reduce(). Fix the race with quarantine_put() by disabling interrupts for the whole duration of quarantine_put(). In combination with on_each_cpu() in quarantine_remove_cache() it ensures that quarantine_remove_cache() either sees the objects in the per-cpu list or in the global list. Fix the race with quarantine_reduce() by protecting quarantine_reduce() with srcu critical section and then doing synchronize_srcu() at the end of quarantine_remove_cache(). I've done some assessment of how good synchronize_srcu() works in this case. And on a 4 CPU VM I see that it blocks waiting for pending read critical sections in about 2-3% of cases. Which looks good to me. I suspect that these races are the root cause of some GPFs that I episodically hit. Previously I did not have any explanation for them. BUG: unable to handle kernel NULL pointer dereference at 00000000000000c8 IP: qlist_free_all+0x2e/0xc0 mm/kasan/quarantine.c:155 PGD 6aeea067 PUD 60ed7067 PMD 0 Oops: 0000 [#1] SMP KASAN Dumping ftrace buffer: (ftrace buffer empty) Modules linked in: CPU: 0 PID: 13667 Comm: syz-executor2 Not tainted 4.10.0+ #60 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 task: ffff88005f948040 task.stack: ffff880069818000 RIP: 0010:qlist_free_all+0x2e/0xc0 mm/kasan/quarantine.c:155 RSP: 0018:ffff88006981f298 EFLAGS: 00010246 RAX: ffffea0000ffff00 RBX: 0000000000000000 RCX: ffffea0000ffff1f RDX: 0000000000000000 RSI: ffff88003fffc3e0 RDI: 0000000000000000 RBP: ffff88006981f2c0 R08: ffff88002fed7bd8 R09: 00000001001f000d R10: 00000000001f000d R11: ffff88006981f000 R12: ffff88003fffc3e0 R13: ffff88006981f2d0 R14: ffffffff81877fae R15: 0000000080000000 FS: 00007fb911a2d700(0000) GS:ffff88003ec00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000000000c8 CR3: 0000000060ed6000 CR4: 00000000000006f0 Call Trace: quarantine_reduce+0x10e/0x120 mm/kasan/quarantine.c:239 kasan_kmalloc+0xca/0xe0 mm/kasan/kasan.c:590 kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:544 slab_post_alloc_hook mm/slab.h:456 [inline] slab_alloc_node mm/slub.c:2718 [inline] kmem_cache_alloc_node+0x1d3/0x280 mm/slub.c:2754 __alloc_skb+0x10f/0x770 net/core/skbuff.c:219 alloc_skb include/linux/skbuff.h:932 [inline] _sctp_make_chunk+0x3b/0x260 net/sctp/sm_make_chunk.c:1388 sctp_make_data net/sctp/sm_make_chunk.c:1420 [inline] sctp_make_datafrag_empty+0x208/0x360 net/sctp/sm_make_chunk.c:746 sctp_datamsg_from_user+0x7e8/0x11d0 net/sctp/chunk.c:266 sctp_sendmsg+0x2611/0x3970 net/sctp/socket.c:1962 inet_sendmsg+0x164/0x5b0 net/ipv4/af_inet.c:761 sock_sendmsg_nosec net/socket.c:633 [inline] sock_sendmsg+0xca/0x110 net/socket.c:643 SYSC_sendto+0x660/0x810 net/socket.c:1685 SyS_sendto+0x40/0x50 net/socket.c:1653 I am not sure about backporting. The bug is quite hard to trigger, I've seen it few times during our massive continuous testing (however, it could be cause of some other episodic stray crashes as it leads to memory corruption...). If it is triggered, the consequences are very bad -- almost definite bad memory corruption. The fix is non trivial and has chances of introducing new bugs. I am also not sure how actively people use KASAN on older releases. [dvyukov@google.com: - sorted includes[ Link: http://lkml.kernel.org/r/20170309094028.51088-1-dvyukov@google.com Link: http://lkml.kernel.org/r/20170308151532.5070-1-dvyukov@google.com Signed-off-by: Dmitry Vyukov <dvyukov@google.com> Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Greg Thelen <gthelen@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-03-09kasan: resched in quarantine_remove_cache()Dmitry Vyukov1-1/+8
We see reported stalls/lockups in quarantine_remove_cache() on machines with large amounts of RAM. quarantine_remove_cache() needs to scan whole quarantine in order to take out all objects belonging to the cache. Quarantine is currently 1/32-th of RAM, e.g. on a machine with 256GB of memory that will be 8GB. Moreover quarantine scanning is a walk over uncached linked list, which is slow. Add cond_resched() after scanning of each non-empty batch of objects. Batches are specifically kept of reasonable size for quarantine_put(). On a machine with 256GB of RAM we should have ~512 non-empty batches, each with 16MB of objects. Link: http://lkml.kernel.org/r/20170308154239.25440-1-dvyukov@google.com Signed-off-by: Dmitry Vyukov <dvyukov@google.com> Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Greg Thelen <gthelen@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>
2017-03-09mm: do not call mem_cgroup_free() from within mem_cgroup_alloc()Tahsin Erdogan1-3/+8
mem_cgroup_free() indirectly calls wb_domain_exit() which is not prepared to deal with a struct wb_domain object that hasn't executed wb_domain_init(). For instance, the following warning message is printed by lockdep if alloc_percpu() fails in mem_cgroup_alloc(): INFO: trying to register non-static key. the code is fine but needs lockdep annotation. turning off the locking correctness validator. CPU: 1 PID: 1950 Comm: mkdir Not tainted 4.10.0+ #151 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 Call Trace: dump_stack+0x67/0x99 register_lock_class+0x36d/0x540 __lock_acquire+0x7f/0x1a30 lock_acquire+0xcc/0x200 del_timer_sync+0x3c/0xc0 wb_domain_exit+0x14/0x20 mem_cgroup_free+0x14/0x40 mem_cgroup_css_alloc+0x3f9/0x620 cgroup_apply_control_enable+0x190/0x390 cgroup_mkdir+0x290/0x3d0 kernfs_iop_mkdir+0x58/0x80 vfs_mkdir+0x10e/0x1a0 SyS_mkdirat+0xa8/0xd0 SyS_mkdir+0x14/0x20 entry_SYSCALL_64_fastpath+0x18/0xad Add __mem_cgroup_free() which skips wb_domain_exit(). This is used by both mem_cgroup_free() and mem_cgroup_alloc() clean up. Fixes: 0b8f73e104285 ("mm: memcontrol: clean up alloc, online, offline, free functions") Link: http://lkml.kernel.org/r/20170306192122.24262-1-tahsin@google.com Signed-off-by: Tahsin Erdogan <tahsin@google.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-03-09thp: fix another corner case of munlock() vs. THPsKirill A. Shutemov1-5/+4
The following test case triggers BUG() in munlock_vma_pages_range(): int main(int argc, char *argv[]) { int fd; system("mount -t tmpfs -o huge=always none /mnt"); fd = open("/mnt/test", O_CREAT | O_RDWR); ftruncate(fd, 4UL << 20); mmap(NULL, 4UL << 20, PROT_READ | PROT_WRITE, MAP_SHARED | MAP_FIXED | MAP_LOCKED, fd, 0); mmap(NULL, 4096, PROT_READ | PROT_WRITE, MAP_SHARED | MAP_LOCKED, fd, 0); munlockall(); return 0; } The second mmap() create PTE-mapping of the first huge page in file. It makes kernel munlock the page as we never keep PTE-mapped page mlocked. On munlockall() when we handle vma created by the first mmap(), munlock_vma_page() returns page_mask == 0, as the page is not mlocked anymore. On next iteration follow_page_mask() return tail page, but page_mask is HPAGE_NR_PAGES - 1. It makes us skip to the first tail page of the next huge page and step on VM_BUG_ON_PAGE(PageMlocked(page)). The fix is not use the page_mask from follow_page_mask() at all. It has no use for us. Link: http://lkml.kernel.org/r/20170302150252.34120-1-kirill.shutemov@linux.intel.com Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: <stable@vger.kernel.org> [4.5+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-03-09rmap: fix NULL-pointer dereference on THP munlockingKirill A. Shutemov1-6/+7
The following test case triggers NULL-pointer derefernce in try_to_unmap_one(): #include <fcntl.h> #include <stdlib.h> #include <unistd.h> #include <sys/mman.h> int main(int argc, char *argv[]) { int fd; system("mount -t tmpfs -o huge=always none /mnt"); fd = open("/mnt/test", O_CREAT | O_RDWR); ftruncate(fd, 2UL << 20); mmap(NULL, 2UL << 20, PROT_READ | PROT_WRITE, MAP_SHARED | MAP_FIXED | MAP_LOCKED, fd, 0); mmap(NULL, 2UL << 20, PROT_READ | PROT_WRITE, MAP_SHARED | MAP_LOCKED, fd, 0); munlockall(); return 0; } Apparently, there's a case when we call try_to_unmap() on huge PMDs: it's TTU_MUNLOCK. Let's handle this case correctly. Fixes: c7ab0d2fdc84 ("mm: convert try_to_unmap_one() to use page_vma_mapped_walk()") Link: http://lkml.kernel.org/r/20170302151159.30592-1-kirill.shutemov@linux.intel.com Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-03-09mm/memblock.c: fix memblock_next_valid_pfn()AKASHI Takahiro1-1/+4
Obviously, we should not access memblock.memory.regions[right] if 'right' is outside of [0..memblock.memory.cnt>. Fixes: b92df1de5d28 ("mm: page_alloc: skip over regions of invalid pfns where possible") Link: http://lkml.kernel.org/r/20170303023745.9104-1-takahiro.akashi@linaro.org Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org> Cc: Paul Burton <paul.burton@imgtec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-03-09userfaultfd: non-cooperative: userfaultfd_remove revalidate vma in MADV_DONTNEEDAndrea Arcangeli1-3/+41
userfaultfd_remove() has to be execute before zapping the pagetables or UFFDIO_COPY could keep filling pages after zap_page_range returned, which would result in non zero data after a MADV_DONTNEED. However userfaultfd_remove() may have to release the mmap_sem. This was handled correctly in MADV_REMOVE, but MADV_DONTNEED accessed a potentially stale vma (the very vma passed to zap_page_range(vma, ...)). The fix consists in revalidating the vma in case userfaultfd_remove() had to release the mmap_sem. This also optimizes away an unnecessary down_read/up_read in the MADV_REMOVE case if UFFD_EVENT_FORK had to be delivered. It all remains zero runtime cost in case CONFIG_USERFAULTFD=n as userfaultfd_remove() will be defined as "true" at build time. Link: http://lkml.kernel.org/r/20170302173738.18994-3-aarcange@redhat.com Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Acked-by: Mike Rapoport <rppt@linux.vnet.ibm.com> Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Pavel Emelyanov <xemul@parallels.com> Cc: Hillf Danton <hillf.zj@alibaba-inc.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-03-09mm/cgroup: avoid panic when init with low memoryLaurent Dufour1-2/+5
The system may panic when initialisation is done when almost all the memory is assigned to the huge pages using the kernel command line parameter hugepage=xxxx. Panic may occur like this: Unable to handle kernel paging request for data at address 0x00000000 Faulting instruction address: 0xc000000000302b88 Oops: Kernel access of bad area, sig: 11 [#1] SMP NR_CPUS=2048 [ 0.082424] NUMA pSeries Modules linked in: CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.9.0-15-generic #16-Ubuntu task: c00000021ed01600 task.stack: c00000010d108000 NIP: c000000000302b88 LR: c000000000270e04 CTR: c00000000016cfd0 REGS: c00000010d10b2c0 TRAP: 0300 Not tainted (4.9.0-15-generic) MSR: 8000000002009033 <SF,VEC,EE,ME,IR,DR,RI,LE>[ 0.082770] CR: 28424422 XER: 00000000 CFAR: c0000000003d28b8 DAR: 0000000000000000 DSISR: 40000000 SOFTE: 1 GPR00: c000000000270e04 c00000010d10b540 c00000000141a300 c00000010fff6300 GPR04: 0000000000000000 00000000026012c0 c00000010d10b630 0000000487ab0000 GPR08: 000000010ee90000 c000000001454fd8 0000000000000000 0000000000000000 GPR12: 0000000000004400 c00000000fb80000 00000000026012c0 00000000026012c0 GPR16: 00000000026012c0 0000000000000000 0000000000000000 0000000000000002 GPR20: 000000000000000c 0000000000000000 0000000000000000 00000000024200c0 GPR24: c0000000016eef48 0000000000000000 c00000010fff7d00 00000000026012c0 GPR28: 0000000000000000 c00000010fff7d00 c00000010fff6300 c00000010d10b6d0 NIP mem_cgroup_soft_limit_reclaim+0xf8/0x4f0 LR do_try_to_free_pages+0x1b4/0x450 Call Trace: do_try_to_free_pages+0x1b4/0x450 try_to_free_pages+0xf8/0x270 __alloc_pages_nodemask+0x7a8/0xff0 new_slab+0x104/0x8e0 ___slab_alloc+0x620/0x700 __slab_alloc+0x34/0x60 kmem_cache_alloc_node_trace+0xdc/0x310 mem_cgroup_init+0x158/0x1c8 do_one_initcall+0x68/0x1d0 kernel_init_freeable+0x278/0x360 kernel_init+0x24/0x170 ret_from_kernel_thread+0x5c/0x74 Instruction dump: eb81ffe0 eba1ffe8 ebc1fff0 ebe1fff8 4e800020 3d230001 e9499a42 3d220004 3929acd8 794a1f24 7d295214 eac90100 <e9360000> 2fa90000 419eff74 3b200000 ---[ end trace 342f5208b00d01b6 ]--- This is a chicken and egg issue where the kernel try to get free memory when allocating per node data in mem_cgroup_init(), but in that path mem_cgroup_soft_limit_reclaim() is called which assumes that these data are allocated. As mem_cgroup_soft_limit_reclaim() is best effort, it should return when these data are not yet allocated. This patch also fixes potential null pointer access in mem_cgroup_remove_from_trees() and mem_cgroup_update_tree(). Link: http://lkml.kernel.org/r/1487856999-16581-2-git-send-email-ldufour@linux.vnet.ibm.com Signed-off-by: Laurent Dufour <ldufour@linux.vnet.ibm.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Balbir Singh <bsingharora@gmail.com> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-03-09mm/vmstats: add thp_split_pud event for clarityYisheng Xie2-1/+4
We added support for PUD-sized transparent hugepages, however we count the event "thp split pud" into thp_split_pmd event. To separate the event count of thp split pud from pmd, add a new event named thp_split_pud. Link: http://lkml.kernel.org/r/1488282380-5076-1-git-send-email-xieyisheng1@huawei.com Signed-off-by: Yisheng Xie <xieyisheng1@huawei.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Sebastian Siewior <bigeasy@linutronix.de> Cc: Hugh Dickins <hughd@google.com> Cc: Christoph Lameter <cl@linux.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Ebru Akagunduz <ebru.akagunduz@gmail.com> Cc: David Rientjes <rientjes@google.com> Cc: Hanjun Guo <guohanjun@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-03-09Merge branch 'for-linus' of git://git.kernel.dk/linux-blockLinus Torvalds1-15/+28
Pull block fixes from Jens Axboe: "Sending this a bit sooner than I otherwise would have, as a fix in the merge window had some unfortunate issues and side effects for some folks. This contains: - Fixes from Jan for the bdi registration/unregistration. These have been tested by the various parties reporting issues, and should be solid at this point. - Also from Jan, fix for axonram gendisk registration. - A stable fix for zram from Johannes. - A small series from Ming, fixing up some long standing issues with blk-mq hardware queue kobject initialization and registration. - A fix for sed opal from Jon, fixing a nonsensical range check and some set-but-not-used variables. - A fix from Neil for a long standing deadlock issue for stacking device drivers. With this in place, dm/md don't have to work around the issue anymore, and can be properly fixed up" * 'for-linus' of git://git.kernel.dk/linux-block: axonram: Fix gendisk handling blk: improve order of bio handling in generic_make_request() Revert "scsi, block: fix duplicate bdi name registration crashes" block: Make del_gendisk() safer for disks without queues bdi: Fix use-after-free in wb_congested_put() block: Allow bdi re-registration block/sed: Fix opal user range check and unused variables zram: set physical queue limits to avoid array out of bounds accesses blk-mq: free hctx->cpumask in release handler of hctx's kobject blk-mq: make lifetime consistent between hctx and its kobject blk-mq: make lifetime consitent between q/ctx and its kobject blk-mq: initialize mq kobjects in blk_mq_init_allocated_queue()
2017-03-09mm: introduce __p4d_alloc()Kirill A. Shutemov1-0/+23
For full 5-level paging we need a helper to allocate p4d page table. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-03-09mm: convert generic code to 5-level pagingKirill A. Shutemov16-104/+472
Convert all non-architecture-specific code to 5-level paging. It's mostly mechanical adding handling one more page table level in places where we deal with pud_t. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-03-08mm, page_alloc: Add missing check for memory holesTony Luck1-1/+2
Commit 13ad59df67f1 ("mm, page_alloc: avoid page_to_pfn() when merging buddies") moved the check for memory holes out of page_is_buddy() and had the callers do the check. But this wasn't done correctly in one place which caused ia64 to crash very early in boot. Update to fix that and make ia64 boot again. [ v2: Vlastimil pointed out we don't need to call page_to_pfn() since we already have the result of that in "buddy_pfn" ] Fixes: 13ad59df67f1 ("avoid page_to_pfn() when merging buddies") Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-03-08bdi: Fix use-after-free in wb_congested_put()Jan Kara1-15/+21
bdi_writeback_congested structures get created for each blkcg and bdi regardless whether bdi is registered or not. When they are created in unregistered bdi and the request queue (and thus bdi) is then destroyed while blkg still holds reference to bdi_writeback_congested structure, this structure will be referencing freed bdi and last wb_congested_put() will try to remove the structure from already freed bdi. With commit 165a5e22fafb "block: Move bdi_unregister() to del_gendisk()", SCSI started to destroy bdis without calling bdi_unregister() first (previously it was calling bdi_unregister() even for unregistered bdis) and thus the code detaching bdi_writeback_congested in cgwb_bdi_destroy() was not triggered and we started hitting this use-after-free bug. It is enough to boot a KVM instance with virtio-scsi device to trigger this behavior. Fix the problem by detaching bdi_writeback_congested structures in bdi_exit() instead of bdi_unregister(). This is also more logical as they can get attached to bdi regardless whether it ever got registered or not. Fixes: 165a5e22fafb127ecb5914e12e8c32a1f0d3f820 Signed-off-by: Jan Kara <jack@suse.cz> Tested-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-03-08block: Allow bdi re-registrationJan Kara1-0/+7
SCSI can call device_add_disk() several times for one request queue when a device in unbound and bound, creating new gendisk each time. This will lead to bdi being repeatedly registered and unregistered. This was not a big problem until commit 165a5e22fafb "block: Move bdi_unregister() to del_gendisk()" since bdi was only registered repeatedly (bdi_register() handles repeated calls fine, only we ended up leaking reference to gendisk due to overwriting bdi->owner) but unregistered only in blk_cleanup_queue() which didn't get called repeatedly. After 165a5e22fafb we were doing correct bdi_register() - bdi_unregister() cycles however bdi_unregister() is not prepared for it. So make sure bdi_unregister() cleans up bdi in such a way that it is prepared for a possible following bdi_register() call. An easy way to provoke this behavior is to enable CONFIG_DEBUG_TEST_DRIVER_REMOVE and use scsi_debug driver to create a scsi disk which immediately hangs without this fix. Fixes: 165a5e22fafb127ecb5914e12e8c32a1f0d3f820 Signed-off-by: Jan Kara <jack@suse.cz> Tested-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-03-06percpu: remove unused chunk_alloc parameter from pcpu_get_pages()Tahsin Erdogan1-4/+3
pcpu_get_pages() doesn't use chunk_alloc parameter, remove it. Fixes: fbbb7f4e149f ("percpu: remove the usage of separate populated bitmap in percpu-vm") Signed-off-by: Tahsin Erdogan <tahsin@google.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2017-03-06percpu: acquire pcpu_lock when updating pcpu_nr_empty_pop_pagesTahsin Erdogan1-1/+4
Update to pcpu_nr_empty_pop_pages in pcpu_alloc() is currently done without holding pcpu_lock. This can lead to bad updates to the variable. Add missing lock calls. Fixes: b539b87fed37 ("percpu: implmeent pcpu_nr_empty_pop_pages and chunk->nr_populated") Signed-off-by: Tahsin Erdogan <tahsin@google.com> Signed-off-by: Tejun Heo <tj@kernel.org> Cc: stable@vger.kernel.org # v3.18+
2017-03-03Merge branch 'rebased-statx' of ↵Linus Torvalds1-3/+3
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull vfs 'statx()' update from Al Viro. This adds the new extended stat() interface that internally subsumes our previous stat interfaces, and allows user mode to specify in more detail what kind of information it wants. It also allows for some explicit synchronization information to be passed to the filesystem, which can be relevant for network filesystems: is the cached value ok, or do you need open/close consistency, or what? From David Howells. Andreas Dilger points out that the first version of the extended statx interface was posted June 29, 2010: https://www.spinics.net/lists/linux-fsdevel/msg33831.html * 'rebased-statx' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: statx: Add a system call to make enhanced file info available
2017-03-03Merge branch 'WIP.sched-core-for-linus' of ↵Linus Torvalds34-11/+70
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull sched.h split-up from Ingo Molnar: "The point of these changes is to significantly reduce the <linux/sched.h> header footprint, to speed up the kernel build and to have a cleaner header structure. After these changes the new <linux/sched.h>'s typical preprocessed size goes down from a previous ~0.68 MB (~22K lines) to ~0.45 MB (~15K lines), which is around 40% faster to build on typical configs. Not much changed from the last version (-v2) posted three weeks ago: I eliminated quirks, backmerged fixes plus I rebased it to an upstream SHA1 from yesterday that includes most changes queued up in -next plus all sched.h changes that were pending from Andrew. I've re-tested the series both on x86 and on cross-arch defconfigs, and did a bisectability test at a number of random points. I tried to test as many build configurations as possible, but some build breakage is probably still left - but it should be mostly limited to architectures that have no cross-compiler binaries available on kernel.org, and non-default configurations" * 'WIP.sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (146 commits) sched/headers: Clean up <linux/sched.h> sched/headers: Remove #ifdefs from <linux/sched.h> sched/headers: Remove the <linux/topology.h> include from <linux/sched.h> sched/headers, hrtimer: Remove the <linux/wait.h> include from <linux/hrtimer.h> sched/headers, x86/apic: Remove the <linux/pm.h> header inclusion from <asm/apic.h> sched/headers, timers: Remove the <linux/sysctl.h> include from <linux/timer.h> sched/headers: Remove <linux/magic.h> from <linux/sched/task_stack.h> sched/headers: Remove <linux/sched.h> from <linux/sched/init.h> sched/core: Remove unused prefetch_stack() sched/headers: Remove <linux/rculist.h> from <linux/sched.h> sched/headers: Remove the 'init_pid_ns' prototype from <linux/sched.h> sched/headers: Remove <linux/signal.h> from <linux/sched.h> sched/headers: Remove <linux/rwsem.h> from <linux/sched.h> sched/headers: Remove the runqueue_is_locked() prototype sched/headers: Remove <linux/sched.h> from <linux/sched/hotplug.h> sched/headers: Remove <linux/sched.h> from <linux/sched/debug.h> sched/headers: Remove <linux/sched.h> from <linux/sched/nohz.h> sched/headers: Remove <linux/sched.h> from <linux/sched/stat.h> sched/headers: Remove the <linux/gfp.h> include from <linux/sched.h> sched/headers: Remove <linux/rtmutex.h> from <linux/sched.h> ...
2017-03-02statx: Add a system call to make enhanced file info availableDavid Howells1-3/+3
Add a system call to make extended file information available, including file creation and some attribute flags where available through the underlying filesystem. The getattr inode operation is altered to take two additional arguments: a u32 request_mask and an unsigned int flags that indicate the synchronisation mode. This change is propagated to the vfs_getattr*() function. Functions like vfs_stat() are now inline wrappers around new functions vfs_statx() and vfs_statx_fd() to reduce stack usage. ======== OVERVIEW ======== The idea was initially proposed as a set of xattrs that could be retrieved with getxattr(), but the general preference proved to be for a new syscall with an extended stat structure. A number of requests were gathered for features to be included. The following have been included: (1) Make the fields a consistent size on all arches and make them large. (2) Spare space, request flags and information flags are provided for future expansion. (3) Better support for the y2038 problem [Arnd Bergmann] (tv_sec is an __s64). (4) Creation time: The SMB protocol carries the creation time, which could be exported by Samba, which will in turn help CIFS make use of FS-Cache as that can be used for coherency data (stx_btime). This is also specified in NFSv4 as a recommended attribute and could be exported by NFSD [Steve French]. (5) Lightweight stat: Ask for just those details of interest, and allow a netfs (such as NFS) to approximate anything not of interest, possibly without going to the server [Trond Myklebust, Ulrich Drepper, Andreas Dilger] (AT_STATX_DONT_SYNC). (6) Heavyweight stat: Force a netfs to go to the server, even if it thinks its cached attributes are up to date [Trond Myklebust] (AT_STATX_FORCE_SYNC). And the following have been left out for future extension: (7) Data version number: Could be used by userspace NFS servers [Aneesh Kumar]. Can also be used to modify fill_post_wcc() in NFSD which retrieves i_version directly, but has just called vfs_getattr(). It could get it from the kstat struct if it used vfs_xgetattr() instead. (There's disagreement on the exact semantics of a single field, since not all filesystems do this the same way). (8) BSD stat compatibility: Including more fields from the BSD stat such as creation time (st_btime) and inode generation number (st_gen) [Jeremy Allison, Bernd Schubert]. (9) Inode generation number: Useful for FUSE and userspace NFS servers [Bernd Schubert]. (This was asked for but later deemed unnecessary with the open-by-handle capability available and caused disagreement as to whether it's a security hole or not). (10) Extra coherency data may be useful in making backups [Andreas Dilger]. (No particular data were offered, but things like last backup timestamp, the data version number and the DOS archive bit would come into this category). (11) Allow the filesystem to indicate what it can/cannot provide: A filesystem can now say it doesn't support a standard stat feature if that isn't available, so if, for instance, inode numbers or UIDs don't exist or are fabricated locally... (This requires a separate system call - I have an fsinfo() call idea for this). (12) Store a 16-byte volume ID in the superblock that can be returned in struct xstat [Steve French]. (Deferred to fsinfo). (13) Include granularity fields in the time data to indicate the granularity of each of the times (NFSv4 time_delta) [Steve French]. (Deferred to fsinfo). (14) FS_IOC_GETFLAGS value. These could be translated to BSD's st_flags. Note that the Linux IOC flags are a mess and filesystems such as Ext4 define flags that aren't in linux/fs.h, so translation in the kernel may be a necessity (or, possibly, we provide the filesystem type too). (Some attributes are made available in stx_attributes, but the general feeling was that the IOC flags were to ext[234]-specific and shouldn't be exposed through statx this way). (15) Mask of features available on file (eg: ACLs, seclabel) [Brad Boyer, Michael Kerrisk]. (Deferred, probably to fsinfo. Finding out if there's an ACL or seclabal might require extra filesystem operations). (16) Femtosecond-resolution timestamps [Dave Chinner]. (A __reserved field has been left in the statx_timestamp struct for this - if there proves to be a need). (17) A set multiple attributes syscall to go with this. =============== NEW SYSTEM CALL =============== The new system call is: int ret = statx(int dfd, const char *filename, unsigned int flags, unsigned int mask, struct statx *buffer); The dfd, filename and flags parameters indicate the file to query, in a similar way to fstatat(). There is no equivalent of lstat() as that can be emulated with statx() by passing AT_SYMLINK_NOFOLLOW in flags. There is also no equivalent of fstat() as that can be emulated by passing a NULL filename to statx() with the fd of interest in dfd. Whether or not statx() synchronises the attributes with the backing store can be controlled by OR'ing a value into the flags argument (this typically only affects network filesystems): (1) AT_STATX_SYNC_AS_STAT tells statx() to behave as stat() does in this respect. (2) AT_STATX_FORCE_SYNC will require a network filesystem to synchronise its attributes with the server - which might require data writeback to occur to get the timestamps correct. (3) AT_STATX_DONT_SYNC will suppress synchronisation with the server in a network filesystem. The resulting values should be considered approximate. mask is a bitmask indicating the fields in struct statx that are of interest to the caller. The user should set this to STATX_BASIC_STATS to get the basic set returned by stat(). It should be noted that asking for more information may entail extra I/O operations. buffer points to the destination for the data. This must be 256 bytes in size. ====================== MAIN ATTRIBUTES RECORD ====================== The following structures are defined in which to return the main attribute set: struct statx_timestamp { __s64 tv_sec; __s32 tv_nsec; __s32 __reserved; }; struct statx { __u32 stx_mask; __u32 stx_blksize; __u64 stx_attributes; __u32 stx_nlink; __u32 stx_uid; __u32 stx_gid; __u16 stx_mode; __u16 __spare0[1]; __u64 stx_ino; __u64 stx_size; __u64 stx_blocks; __u64 __spare1[1]; struct statx_timestamp stx_atime; struct statx_timestamp stx_btime; struct statx_timestamp stx_ctime; struct statx_timestamp stx_mtime; __u32 stx_rdev_major; __u32 stx_rdev_minor; __u32 stx_dev_major; __u32 stx_dev_minor; __u64 __spare2[14]; }; The defined bits in request_mask and stx_mask are: STATX_TYPE Want/got stx_mode & S_IFMT STATX_MODE Want/got stx_mode & ~S_IFMT STATX_NLINK Want/got stx_nlink STATX_UID Want/got stx_uid STATX_GID Want/got stx_gid STATX_ATIME Want/got stx_atime{,_ns} STATX_MTIME Want/got stx_mtime{,_ns} STATX_CTIME Want/got stx_ctime{,_ns} STATX_INO Want/got stx_ino STATX_SIZE Want/got stx_size STATX_BLOCKS Want/got stx_blocks STATX_BASIC_STATS [The stuff in the normal stat struct] STATX_BTIME Want/got stx_btime{,_ns} STATX_ALL [All currently available stuff] stx_btime is the file creation time, stx_mask is a bitmask indicating the data provided and __spares*[] are where as-yet undefined fields can be placed. Time fields are structures with separate seconds and nanoseconds fields plus a reserved field in case we want to add even finer resolution. Note that times will be negative if before 1970; in such a case, the nanosecond fields will also be negative if not zero. The bits defined in the stx_attributes field convey information about a file, how it is accessed, where it is and what it does. The following attributes map to FS_*_FL flags and are the same numerical value: STATX_ATTR_COMPRESSED File is compressed by the fs STATX_ATTR_IMMUTABLE File is marked immutable STATX_ATTR_APPEND File is append-only STATX_ATTR_NODUMP File is not to be dumped STATX_ATTR_ENCRYPTED File requires key to decrypt in fs Within the kernel, the supported flags are listed by: KSTAT_ATTR_FS_IOC_FLAGS [Are any other IOC flags of sufficient general interest to be exposed through this interface?] New flags include: STATX_ATTR_AUTOMOUNT Object is an automount trigger These are for the use of GUI tools that might want to mark files specially, depending on what they are. Fields in struct statx come in a number of classes: (0) stx_dev_*, stx_blksize. These are local system information and are always available. (1) stx_mode, stx_nlinks, stx_uid, stx_gid, stx_[amc]time, stx_ino, stx_size, stx_blocks. These will be returned whether the caller asks for them or not. The corresponding bits in stx_mask will be set to indicate whether they actually have valid values. If the caller didn't ask for them, then they may be approximated. For example, NFS won't waste any time updating them from the server, unless as a byproduct of updating something requested. If the values don't actually exist for the underlying object (such as UID or GID on a DOS file), then the bit won't be set in the stx_mask, even if the caller asked for the value. In such a case, the returned value will be a fabrication. Note that there are instances where the type might not be valid, for instance Windows reparse points. (2) stx_rdev_*. This will be set only if stx_mode indicates we're looking at a blockdev or a chardev, otherwise will be 0. (3) stx_btime. Similar to (1), except this will be set to 0 if it doesn't exist. ======= TESTING ======= The following test program can be used to test the statx system call: samples/statx/test-statx.c Just compile and run, passing it paths to the files you want to examine. The file is built automatically if CONFIG_SAMPLES is enabled. Here's some example output. Firstly, an NFS directory that crosses to another FSID. Note that the AUTOMOUNT attribute is set because transiting this directory will cause d_automount to be invoked by the VFS. [root@andromeda ~]# /tmp/test-statx -A /warthog/data statx(/warthog/data) = 0 results=7ff Size: 4096 Blocks: 8 IO Block: 1048576 directory Device: 00:26 Inode: 1703937 Links: 125 Access: (3777/drwxrwxrwx) Uid: 0 Gid: 4041 Access: 2016-11-24 09:02:12.219699527+0000 Modify: 2016-11-17 10:44:36.225653653+0000 Change: 2016-11-17 10:44:36.225653653+0000 Attributes: 0000000000001000 (-------- -------- -------- -------- -------- -------- ---m---- --------) Secondly, the result of automounting on that directory. [root@andromeda ~]# /tmp/test-statx /warthog/data statx(/warthog/data) = 0 results=7ff Size: 4096 Blocks: 8 IO Block: 1048576 directory Device: 00:27 Inode: 2 Links: 125 Access: (3777/drwxrwxrwx) Uid: 0 Gid: 4041 Access: 2016-11-24 09:02:12.219699527+0000 Modify: 2016-11-17 10:44:36.225653653+0000 Change: 2016-11-17 10:44:36.225653653+0000 Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-03-03sched/headers: Move task_struct::signal and task_struct::sighand types and ↵Ingo Molnar1-1/+1
accessors into <linux/sched/signal.h> task_struct::signal and task_struct::sighand are pointers, which would normally make it straightforward to not define those types in sched.h. That is not so, because the types are accompanied by a myriad of APIs (macros and inline functions) that dereference them. Split the types and the APIs out of sched.h and move them into a new header, <linux/sched/signal.h>. With this change sched.h does not know about 'struct signal' and 'struct sighand' anymore, trying to put accessors into sched.h as a test fails the following way: ./include/linux/sched.h: In function ‘test_signal_types’: ./include/linux/sched.h:2461:18: error: dereferencing pointer to incomplete type ‘struct signal_struct’ ^ This reduces the size and complexity of sched.h significantly. Update all headers and .c code that relied on getting the signal handling functionality from <linux/sched.h> to include <linux/sched/signal.h>. The list of affected files in the preparatory patch was partly generated by grepping for the APIs, and partly by doing coverage build testing, both all[yes|mod|def|no]config builds on 64-bit and 32-bit x86, and an array of cross-architecture builds. Nevertheless some (trivial) build breakage is still expected related to rare Kconfig combinations and in-flight patches to various kernel code, but most of it should be handled by this patch. Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-02Merge branch 'for-linus' of ↵Linus Torvalds2-3/+3
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull vfs pile two from Al Viro: - orangefs fix - series of fs/namei.c cleanups from me - VFS stuff coming from overlayfs tree * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: orangefs: Use RCU for destroy_inode vfs: use helper for calling f_op->fsync() mm: use helper for calling f_op->mmap() vfs: use helpers for calling f_op->{read,write}_iter() vfs: pass type instead of fn to do_{loop,iter}_readv_writev() vfs: extract common parts of {compat_,}do_readv_writev() vfs: wrap write f_ops with file_{start,end}_write() vfs: deny copy_file_range() for non regular files vfs: deny fallocate() on directory vfs: create vfs helper vfs_tmpfile() namei.c: split unlazy_walk() namei.c: fold the check for DCACHE_OP_REVALIDATE into d_revalidate() lookup_fast(): clean up the logics around the fallback to non-rcu mode namei: fold unlazy_link() into its sole caller
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