On 7/24/19 2:13 PM, Qian Cai wrote:
On Wed, 2019-07-10 at 17:43 -0400, Qian Cai wrote:
Running LTP oom01 test case with swap triggers a crash below. Revert the
series
"Make deferred split shrinker memcg aware" [1] seems fix the issue.
You might want to look harder on this commit, as reverted it alone on the top of
5.2.0-next-20190711 fixed the issue.
aefde94195ca mm: thp: make deferred split shrinker memcg aware [1]
[1] https://lore.kernel.org/linux-mm/1561507361-59349-5-git-send-email-yang.shi@
linux.alibaba.com/
This is the real meat of the patch series, which converted to memcg
deferred split queue actually.
list_del corruption. prev->next should be ffffea0022b10098, but was
0000000000000000
Finally I could reproduce the list corruption issue on my machine with
THP swap (swap device is fast device). I should checked this with you at
the first place. The problem can't be reproduced with rotate swap
device. So, I'm supposed you were using THP swap too.
Actually, I found two issues with THP swap:
1. free_transhuge_page() is called in reclaim path instead of put_page.
The mem_cgroup_uncharge() is called before free_transhuge_page() in
reclaim path, which causes page->mem_cgroup is NULL so the wrong
deferred_split_queue would be used, so the THP was not deleted from the
memcg's list at all. Then the page might be split or reused later,
page->mapping would be override.
2. There is a race condition caused by try_to_unmap() with THP swap. The
try_to_unmap() just calls page_remove_rmap() to add THP to deferred
split queue in reclaim path. This might cause the below race condition
to corrupt the list:
A B
deferred_split_scan
list_move
try_to_unmap
list_add_tail
list_splice <-- The list might get corrupted here
free_transhuge_page
list_del <--
kernel bug triggered
I hope the below patch would solve your problem (tested locally).
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index b7f709d..d6612ec 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2830,6 +2830,19 @@ void deferred_split_huge_page(struct page *page)
VM_BUG_ON_PAGE(!PageTransHuge(page), page);
+ /*
+ * The try_to_unmap() in page reclaim path might reach here too,
+ * this may cause a race condition to corrupt deferred split queue.
+ * And, if page reclaim is already handling the same page, it is
+ * unnecessary to handle it again in shrinker.
+ *
+ * Check PageSwapCache to determine if the page is being
+ * handled by page reclaim since THP swap would add the page into
+ * swap cache before reaching try_to_unmap().
+ */
+ if (PageSwapCache(page))
+ return;
+
spin_lock_irqsave(&ds_queue->split_queue_lock, flags);
if (list_empty(page_deferred_list(page))) {
count_vm_event(THP_DEFERRED_SPLIT_PAGE);
diff --git a/mm/vmscan.c b/mm/vmscan.c
index a0301ed..40c684a 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1485,10 +1485,9 @@ static unsigned long shrink_page_list(struct
list_head *page_list,
* Is there need to periodically free_page_list? It would
* appear not as the counts should be low
*/
- if (unlikely(PageTransHuge(page))) {
- mem_cgroup_uncharge(page);
+ if (unlikely(PageTransHuge(page)))
(*get_compound_page_dtor(page))(page);
- } else
+ else
list_add(&page->lru, &free_pages);
continue;
@@ -1909,7 +1908,6 @@ static unsigned noinline_for_stack
move_pages_to_lru(struct lruvec *lruvec,
if (unlikely(PageCompound(page))) {
spin_unlock_irq(&pgdat->lru_lock);
- mem_cgroup_uncharge(page);
(*get_compound_page_dtor(page))(page);
spin_lock_irq(&pgdat->lru_lock);
} else
[ 685.284254][ T3456] ------------[ cut here ]------------
[ 685.289616][ T3456] kernel BUG at lib/list_debug.c:53!
[ 685.294808][ T3456] invalid opcode: 0000 [#1] SMP DEBUG_PAGEALLOC KASAN NOPTI
[ 685.301998][ T3456] CPU: 5 PID: 3456 Comm: oom01 Tainted:
G W 5.2.0-next-20190711+ #3
[ 685.311193][ T3456] Hardware name: HPE ProLiant DL385 Gen10/ProLiant DL385
Gen10, BIOS A40 06/24/2019
[ 685.320485][ T3456] RIP: 0010:__list_del_entry_valid+0x8b/0xb6
[ 685.326364][ T3456] Code: f1 e0 ff 49 8b 55 08 4c 39 e2 75 2c 5b b8 01 00 00
00 41 5c 41 5d 5d c3 4c 89 e2 48 89 de 48 c7 c7 c0 5a 73 a3 e8 d9 fa bc ff <0f>
0b 48 c7 c7 60 a0 e1 a3 e8 13 52 01 00 4c 89 e6 48 c7 c7 20 5b
[ 685.345956][ T3456] RSP: 0018:ffff888e0c8a73c0 EFLAGS: 00010082
[ 685.351920][ T3456] RAX: 0000000000000054 RBX: ffffea0022b10098 RCX:
ffffffffa2d5d708
[ 685.359807][ T3456] RDX: 0000000000000000 RSI: 0000000000000008 RDI:
ffff8888442bd380
[ 685.367693][ T3456] RBP: ffff888e0c8a73d8 R08: ffffed1108857a71 R09:
ffffed1108857a70
[ 685.375577][ T3456] R10: ffffed1108857a70 R11: ffff8888442bd387 R12:
0000000000000000
[ 685.383462][ T3456] R13: 0000000000000000 R14: ffffea0022b10034 R15:
ffffea0022b10098
[ 685.391348][ T3456] FS: 00007fbe26db4700(0000) GS:ffff888844280000(0000)
knlGS:0000000000000000
[ 685.400194][ T3456] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 685.406681][ T3456] CR2: 00007fbcabb3f000 CR3: 0000001012e44000 CR4:
00000000001406a0
[ 685.414563][ T3456] Call Trace:
[ 685.417736][ T3456] deferred_split_scan+0x337/0x740
[ 685.422741][ T3456] ? split_huge_page_to_list+0xe10/0xe10
[ 685.428272][ T3456] ? __radix_tree_lookup+0x12d/0x1e0
[ 685.433453][ T3456] ? node_tag_get.part.0.constprop.6+0x40/0x40
[ 685.439505][ T3456] do_shrink_slab+0x244/0x5a0
[ 685.444071][ T3456] shrink_slab+0x253/0x440
[ 685.448375][ T3456] ? unregister_shrinker+0x110/0x110
[ 685.453551][ T3456] ? kasan_check_read+0x11/0x20
[ 685.458291][ T3456] ? mem_cgroup_protected+0x20f/0x260
[ 685.463555][ T3456] shrink_node+0x31e/0xa30
[ 685.467858][ T3456] ? shrink_node_memcg+0x1560/0x1560
[ 685.473036][ T3456] ? ktime_get+0x93/0x110
[ 685.477250][ T3456] do_try_to_free_pages+0x22f/0x820
[ 685.482338][ T3456] ? shrink_node+0xa30/0xa30
[ 685.486815][ T3456] ? kasan_check_read+0x11/0x20
[ 685.491556][ T3456] ? check_chain_key+0x1df/0x2e0
[ 685.496383][ T3456] try_to_free_pages+0x242/0x4d0
[ 685.501209][ T3456] ? do_try_to_free_pages+0x820/0x820
[ 685.506476][ T3456] __alloc_pages_nodemask+0x9ce/0x1bc0
[ 685.511826][ T3456] ? gfp_pfmemalloc_allowed+0xc0/0xc0
[ 685.517089][ T3456] ? kasan_check_read+0x11/0x20
[ 685.521826][ T3456] ? check_chain_key+0x1df/0x2e0
[ 685.526657][ T3456] ? do_anonymous_page+0x343/0xe30
[ 685.531658][ T3456] ? lock_downgrade+0x390/0x390
[ 685.536399][ T3456] ? get_kernel_page+0xa0/0xa0
[ 685.541050][ T3456] ? __lru_cache_add+0x108/0x160
[ 685.545879][ T3456] alloc_pages_vma+0x89/0x2c0
[ 685.550444][ T3456] do_anonymous_page+0x3e1/0xe30
[ 685.555271][ T3456] ? __update_load_avg_cfs_rq+0x2c/0x490
[ 685.560796][ T3456] ? finish_fault+0x120/0x120
[ 685.565361][ T3456] ? alloc_pages_vma+0x21e/0x2c0
[ 685.570187][ T3456] handle_pte_fault+0x457/0x12c0
[ 685.575014][ T3456] __handle_mm_fault+0x79a/0xa50
[ 685.579841][ T3456] ? vmf_insert_mixed_mkwrite+0x20/0x20
[ 685.585280][ T3456] ? kasan_check_read+0x11/0x20
[ 685.590021][ T3456] ? __count_memcg_events+0x8b/0x1c0
[ 685.595196][ T3456] handle_mm_fault+0x17f/0x370
[ 685.599850][ T3456] __do_page_fault+0x25b/0x5d0
[ 685.604501][ T3456] do_page_fault+0x4c/0x2cf
[ 685.608892][ T3456] ? page_fault+0x5/0x20
[ 685.613019][ T3456] page_fault+0x1b/0x20
[ 685.617058][ T3456] RIP: 0033:0x410be0
[ 685.620840][ T3456] Code: 89 de e8 e3 23 ff ff 48 83 f8 ff 0f 84 86 00 00 00
48 89 c5 41 83 fc 02 74 28 41 83 fc 03 74 62 e8 95 29 ff ff 31 d2 48 98 90 <c6>
44 15 00 07 48 01 c2 48 39 d3 7f f3 31 c0 5b 5d 41 5c c3 0f 1f
[ 68[ 687.120156][ T3456] Shutting down cpus with NMI
[ 687.124731][ T3456] Kernel Offset: 0x21800000 from 0xffffffff81000000
(relocation range: 0xffffffff80000000-0xffffffffbfffffff)
[ 687.136389][ T3456] ---[ end Kernel panic - not syncing: Fatal exception ]---
