[PATCH] mm/rmap: fix BUG at rmap_walk
From: Wanpeng Li
Date: Wed Dec 18 2013 - 19:16:55 EST
page_get_anon_vma() called in page_referenced_anon() will lock and
increase the refcount of anon_vma, page won't be locked for anonymous
page. This patch fix it by skip check anonymous page locked.
[ 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>
Reported-by: Sasha Levin <sasha.levin@xxxxxxxxxx>
Signed-off-by: Wanpeng Li <liwanp@xxxxxxxxxxxxxxxxxx>
---
mm/rmap.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/mm/rmap.c b/mm/rmap.c
index d792e71..daf20d5 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -1660,7 +1660,8 @@ done:
int rmap_walk(struct page *page, struct rmap_walk_control *rwc)
{
- VM_BUG_ON(!PageLocked(page));
+ if (!PageAnon(page) || PageKsm(page))
+ VM_BUG_ON(!PageLocked(page));
if (unlikely(PageKsm(page)))
return rmap_walk_ksm(page, rwc);
--
1.8.3.2
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