On 4/27/22 3:12 PM, HORIGUCHI NAOYA(堀口 直也) wrote:
On Wed, Apr 27, 2022 at 02:10:17PM +0800, Xu Yu wrote:
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@xxxxxxxxx>
Cc: Naoya Horiguchi <naoya.horiguchi@xxxxxxx>
Signed-off-by: Xu Yu <xuyu@xxxxxxxxxxxxxxxxx>
Reviewed-by: Naoya Horiguchi <naoya.horiguchi@xxxxxxx>
What to do on -stable?
The older version was backported to 5.15.z and 5.17.z, so if you choose
to send this to stable, 1/2 should be also sent to stable.
IMHO, I would like to view v3 as an optimization of v2, since the older version
is also capable of fixing this bug accurately. Since the Fixes tag has already
been added to the older version, let's keep -stable to use the older version.
Anyway, the older version is not bad. :)
Thanks,
Naoya Horiguchi
--
Thanks,
Yu
