From: Xu Yu <xuyu@linux.alibaba.com>
To: linux-mm@kvack.org
Cc: akpm@linux-foundation.org, naoya.horiguchi@nec.com, shy828301@gmail.com
Subject: [PATCH 2/2] mm/huge_memory: do not overkill when splitting huge_zero_page
Date: Wed, 27 Apr 2022 14:10:17 +0800 [thread overview]
Message-ID: <d4fab301a5debd792527696add16132f53a80cc9.1651039624.git.xuyu@linux.alibaba.com> (raw)
In-Reply-To: <cover.1651039624.git.xuyu@linux.alibaba.com>
Kernel panic when injecting memory_failure for the global
huge_zero_page, when CONFIG_DEBUG_VM is enabled, as follows.
Injecting memory failure for pfn 0x109ff9 at process virtual address 0x20ff9000
page:00000000fb053fc3 refcount:2 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x109e00
head:00000000fb053fc3 order:9 compound_mapcount:0 compound_pincount:0
flags: 0x17fffc000010001(locked|head|node=0|zone=2|lastcpupid=0x1ffff)
raw: 017fffc000010001 0000000000000000 dead000000000122 0000000000000000
raw: 0000000000000000 0000000000000000 00000002ffffffff 0000000000000000
page dumped because: VM_BUG_ON_PAGE(is_huge_zero_page(head))
------------[ cut here ]------------
kernel BUG at mm/huge_memory.c:2499!
invalid opcode: 0000 [#1] PREEMPT SMP PTI
CPU: 6 PID: 553 Comm: split_bug Not tainted 5.18.0-rc1+ #11
Hardware name: Alibaba Cloud Alibaba Cloud ECS, BIOS 3288b3c 04/01/2014
RIP: 0010:split_huge_page_to_list+0x66a/0x880
Code: 84 9b fb ff ff 48 8b 7c 24 08 31 f6 e8 9f 5d 2a 00 b8 b8 02 00 00 e9 e8 fb ff ff 48 c7 c6 e8 47 3c 82 4c b
RSP: 0018:ffffc90000dcbdf8 EFLAGS: 00010246
RAX: 000000000000003c RBX: 0000000000000001 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff823e4c4f RDI: 00000000ffffffff
RBP: ffff88843fffdb40 R08: 0000000000000000 R09: 00000000fffeffff
R10: ffffc90000dcbc48 R11: ffffffff82d68448 R12: ffffea0004278000
R13: ffffffff823c6203 R14: 0000000000109ff9 R15: ffffea000427fe40
FS: 00007fc375a26740(0000) GS:ffff88842fd80000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fc3757c9290 CR3: 0000000102174006 CR4: 00000000003706e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
try_to_split_thp_page+0x3a/0x130
memory_failure+0x128/0x800
madvise_inject_error.cold+0x8b/0xa1
__x64_sys_madvise+0x54/0x60
do_syscall_64+0x35/0x80
entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7fc3754f8bf9
Code: 01 00 48 81 c4 80 00 00 00 e9 f1 fe ff ff 0f 1f 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 8
RSP: 002b:00007ffeda93a1d8 EFLAGS: 00000217 ORIG_RAX: 000000000000001c
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fc3754f8bf9
RDX: 0000000000000064 RSI: 0000000000003000 RDI: 0000000020ff9000
RBP: 00007ffeda93a200 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000217 R12: 0000000000400490
R13: 00007ffeda93a2e0 R14: 0000000000000000 R15: 0000000000000000
We think that raising BUG is overkilling for splitting huge_zero_page,
the huge_zero_page can't be met from normal paths other than memory
failure, but memory failure is a valid caller. So we tend to replace the
BUG to WARN + returning -EBUSY, and thus the panic above won't happen
again.
Suggested-by: Yang Shi <shy828301@gmail.com>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Signed-off-by: Xu Yu <xuyu@linux.alibaba.com>
---
mm/huge_memory.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index c468fee595ff..3bb464509518 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2496,10 +2496,12 @@ int split_huge_page_to_list(struct page *page, struct list_head *list)
int extra_pins, ret;
pgoff_t end;
- VM_BUG_ON_PAGE(is_huge_zero_page(head), head);
VM_BUG_ON_PAGE(!PageLocked(head), head);
VM_BUG_ON_PAGE(!PageCompound(head), head);
+ if (VM_WARN_ON_ONCE_PAGE(is_huge_zero_page(head), head))
+ return -EBUSY;
+
if (PageWriteback(head))
return -EBUSY;
--
2.20.1.2432.ga663e714
next prev parent reply other threads:[~2022-04-27 6:10 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-27 6:10 [PATCH 0/2] mm/memory-failure: rework fix on huge_zero_page splitting Xu Yu
2022-04-27 6:10 ` [PATCH 1/2] Revert "mm/memory-failure.c: skip huge_zero_page in memory_failure()" Xu Yu
2022-04-27 21:13 ` Yang Shi
2022-04-28 2:23 ` Miaohe Lin
2022-04-27 6:10 ` Xu Yu [this message]
2022-04-27 7:12 ` [PATCH 2/2] mm/huge_memory: do not overkill when splitting huge_zero_page HORIGUCHI NAOYA(堀口 直也)
2022-04-27 7:37 ` Yu Xu
2022-04-27 19:00 ` Andrew Morton
2022-04-27 9:01 ` kernel test robot
2022-04-27 9:48 ` Yu Xu
2022-04-27 9:36 ` kernel test robot
2022-04-27 9:44 ` [PATCH 2/2 RESEND] " Xu Yu
2022-04-27 21:15 ` Yang Shi
2022-04-28 2:25 ` Miaohe Lin
2022-04-28 16:04 ` David Hildenbrand
2022-04-28 17:18 ` Yang Shi
2022-04-28 1:59 ` [PATCH 2/2] " kernel test robot
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