Subject: + mm-rmap-use-rmap_walk-in-page_referenced-fix.patch added to -mm tree To: liwanp@xxxxxxxxxxxxxxxxxx,bob.liu@xxxxxxxxxx,dhillf@xxxxxxxxx,hughd@xxxxxxxxxx,iamjoonsoo.kim@xxxxxxx,mgorman@xxxxxxx,mingo@xxxxxxxxxx,n-horiguchi@xxxxxxxxxxxxx,riel@xxxxxxxxxx,sasha.levin@xxxxxxxxxx From: akpm@xxxxxxxxxxxxxxxxxxxx Date: Thu, 19 Dec 2013 12:03:33 -0800 The patch titled Subject: mm/rmap: fix BUG at rmap_walk has been added to the -mm tree. Its filename is mm-rmap-use-rmap_walk-in-page_referenced-fix.patch This patch should soon appear at http://ozlabs.org/~akpm/mmots/broken-out/mm-rmap-use-rmap_walk-in-page_referenced-fix.patch and later at http://ozlabs.org/~akpm/mmotm/broken-out/mm-rmap-use-rmap_walk-in-page_referenced-fix.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: Wanpeng Li <liwanp@xxxxxxxxxxxxxxxxxx> Subject: mm/rmap: fix BUG at rmap_walk This bug is introduced by commit 37f093cdf(mm/rmap: use rmap_walk() in page_referenced()). page_get_anon_vma() called in page_referenced_anon() will lock and increase the refcount of anon_vma. PageLocked is not required by page_referenced_anon() and there is not any assertion before, commit 37f093cdf introduced this extra BUG_ON() checking for anon page by mistake. This patch fix it by remove rmap_walk()'s VM_BUG_ON() and comment reason why the page must be locked for rmap_walk_ksm() and rmap_walk_file(). [ 588.698828] kernel BUG at mm/rmap.c:1663! [ 588.699380] invalid opcode: 0000 [#2] PREEMPT SMP DEBUG_PAGEALLOC [ 588.700347] Dumping ftrace buffer: [ 588.701186] (ftrace buffer empty) [ 588.702062] Modules linked in: [ 588.702759] CPU: 0 PID: 4647 Comm: kswapd0 Tainted: G D W 3.13.0-rc4-next-20131218-sasha-00012-g1962367-dirty #4155 [ 588.704330] task: ffff880062bcb000 ti: ffff880062450000 task.ti: ffff880062450000 [ 588.705507] RIP: 0010:[<ffffffff81289c80>] [<ffffffff81289c80>] rmap_walk+0x10/0x50 [ 588.706800] RSP: 0018:ffff8800624518d8 EFLAGS: 00010246 [ 588.707515] RAX: 000fffff80080048 RBX: ffffea00000227c0 RCX: 0000000000000000 [ 588.707515] RDX: 0000000000000000 RSI: ffff8800624518e8 RDI: ffffea00000227c0 [ 588.707515] RBP: ffff8800624518d8 R08: ffff8800624518e8 R09: 0000000000000000 [ 588.707515] R10: 0000000000000000 R11: 0000000000000000 R12: ffff8800624519d8 [ 588.707515] R13: 0000000000000000 R14: ffffea00000227e0 R15: 0000000000000000 [ 588.707515] FS: 0000000000000000(0000) GS:ffff880065200000(0000) knlGS:0000000000000000 [ 588.707515] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b [ 588.707515] CR2: 00007fec40cbe0f8 CR3: 00000000c2382000 CR4: 00000000000006f0 [ 588.707515] Stack: [ 588.707515] ffff880062451958 ffffffff81289f4b ffff880062451918 ffffffff81289f80 [ 588.707515] 0000000000000000 0000000000000000 ffffffff8128af60 0000000000000000 [ 588.707515] 0000000000000024 0000000000000000 0000000000000000 0000000000000286 [ 588.707515] Call Trace: [ 588.707515] [<ffffffff81289f4b>] page_referenced+0xcb/0x100 [ 588.707515] [<ffffffff81289f80>] ? page_referenced+0x100/0x100 [ 588.707515] [<ffffffff8128af60>] ? invalid_page_referenced_vma+0x170/0x170 [ 588.707515] [<ffffffff81264302>] shrink_active_list+0x212/0x330 [ 588.707515] [<ffffffff81260e23>] ? inactive_file_is_low+0x33/0x50 [ 588.707515] [<ffffffff812646f5>] shrink_lruvec+0x2d5/0x300 [ 588.707515] [<ffffffff812647b6>] shrink_zone+0x96/0x1e0 [ 588.707515] [<ffffffff81265b06>] kswapd_shrink_zone+0xf6/0x1c0 [ 588.707515] [<ffffffff81265f43>] balance_pgdat+0x373/0x550 [ 588.707515] [<ffffffff81266d63>] kswapd+0x2f3/0x350 [ 588.707515] [<ffffffff81266a70>] ? perf_trace_mm_vmscan_lru_isolate_template+0x120/0x120 [ 588.707515] [<ffffffff8115c9c5>] kthread+0x105/0x110 [ 588.707515] [<ffffffff8115c8c0>] ? set_kthreadd_affinity+0x30/0x30 [ 588.707515] [<ffffffff843a6a7c>] ret_from_fork+0x7c/0xb0 [ 588.707515] [<ffffffff8115c8c0>] ? set_kthreadd_affinity+0x30/0x30 [ 588.707515] Code: c0 48 83 c4 18 89 d0 5b 41 5c 41 5d 41 5e 41 5f c9 c3 66 0f 1f 84 00 00 00 00 00 55 48 89 e5 66 66 66 66 90 48 8b 07 a8 01 75 10 <0f> 0b 66 0f 1f 44 00 0 0 eb fe 66 0f 1f 44 00 00 f6 47 08 01 74 [ 588.707515] RIP [<ffffffff81289c80>] rmap_walk+0x10/0x50 [ 588.707515] RSP <ffff8800624518d8> Signed-off-by: Wanpeng Li <liwanp@xxxxxxxxxxxxxxxxxx> Reported-by: Sasha Levin <sasha.levin@xxxxxxxxxx> Reviewed-by: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx> Cc: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx> Cc: Mel Gorman <mgorman@xxxxxxx> Cc: Hugh Dickins <hughd@xxxxxxxxxx> Cc: Rik van Riel <riel@xxxxxxxxxx> Cc: Ingo Molnar <mingo@xxxxxxxxxx> Cc: Hillf Danton <dhillf@xxxxxxxxx> Cc: Bob Liu <bob.liu@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/ksm.c | 5 +++++ mm/rmap.c | 10 ++++++++-- 2 files changed, 13 insertions(+), 2 deletions(-) diff -puN mm/ksm.c~mm-rmap-use-rmap_walk-in-page_referenced-fix mm/ksm.c --- a/mm/ksm.c~mm-rmap-use-rmap_walk-in-page_referenced-fix +++ a/mm/ksm.c @@ -1899,6 +1899,11 @@ int rmap_walk_ksm(struct page *page, str int search_new_forks = 0; VM_BUG_ON(!PageKsm(page)); + + /* + * Rely on the page lock to protect against concurrent modifications + * to that page's node of the stable tree. + */ VM_BUG_ON(!PageLocked(page)); stable_node = page_stable_node(page); diff -puN mm/rmap.c~mm-rmap-use-rmap_walk-in-page_referenced-fix mm/rmap.c --- a/mm/rmap.c~mm-rmap-use-rmap_walk-in-page_referenced-fix +++ a/mm/rmap.c @@ -1632,6 +1632,14 @@ static int rmap_walk_file(struct page *p struct vm_area_struct *vma; int ret = SWAP_AGAIN; + /* + * The page lock not only makes sure that page->mapping cannot + * suddenly be NULLified by truncation, it makes sure that the + * structure at mapping cannot be freed and reused yet, + * so we can safely take mapping->i_mmap_mutex. + */ + VM_BUG_ON(!PageLocked(page)); + if (!mapping) return ret; mutex_lock(&mapping->i_mmap_mutex); @@ -1663,8 +1671,6 @@ done: int rmap_walk(struct page *page, struct rmap_walk_control *rwc) { - VM_BUG_ON(!PageLocked(page)); - if (unlikely(PageKsm(page))) return rmap_walk_ksm(page, rwc); else if (PageAnon(page)) _ Patches currently in -mm which might be from liwanp@xxxxxxxxxxxxxxxxxx are origin.patch x86-get-pg_data_ts-memory-from-other-node.patch memblock-numa-introduce-flags-field-into-memblock.patch memblock-mem_hotplug-introduce-memblock_hotplug-flag-to-mark-hotpluggable-regions.patch memblock-make-memblock_set_node-support-different-memblock_type.patch acpi-numa-mem_hotplug-mark-hotpluggable-memory-in-memblock.patch acpi-numa-mem_hotplug-mark-all-nodes-the-kernel-resides-un-hotpluggable.patch memblock-mem_hotplug-make-memblock-skip-hotpluggable-regions-if-needed.patch x86-numa-acpi-memory-hotplug-make-movable_node-have-higher-priority.patch mm-rmap-use-rmap_walk-in-page_referenced-fix.patch mm-hwpoison-add-to-hwpoison_inject.patch lib-show_memc-show-num_poisoned_pages-when-oom.patch mm-migrate-add-comment-about-permanent-failure-path.patch mm-migrate-correct-failure-handling-if-hugepage_migration_support.patch mm-migrate-remove-putback_lru_pages-fix-comment-on-putback_movable_pages.patch mm-migrate-remove-unused-function-fail_migrate_page.patch mm-documentation-remove-hopelessly-out-of-date-locking-doc.patch mm-remove-bug_on-from-mlock_vma_page.patch linux-next.patch mm-migratec-fix-set-cpupid-on-page-migration-twice-against-thp.patch mm-migratec-fix-setting-of-cpupid-on-page-migration-twice-against-normal-page.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html