KCSAN: data-race in compact_zone / compact_zone (5)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: c605c39677b9 Merge tag 'io_uring-5.15-2021-09-11' of git:/..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1560c163300000
kernel config: https://syzkaller.appspot.com/x/.config?x=3f570cb9909c0dba
dashboard link: https://syzkaller.appspot.com/bug?extid=7323c3826ca87b949c38
compiler: Debian clang version 11.0.1-2, GNU ld (GNU Binutils for Debian) 2.35.1
CC: [ak...@linux-foundation.org linux-...@vger.kernel.org linu...@kvack.org]

Unfortunately, I don't have any reproducer for this issue yet.

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+7323c3...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in compact_zone / compact_zone

write to 0xffff88823fffad90 of 8 bytes by task 17400 on cpu 1:
update_cached_migrate mm/compaction.c:432 [inline]
isolate_migratepages mm/compaction.c:1919 [inline]
compact_zone+0x1449/0x1ce0 mm/compaction.c:2370
compact_zone_order mm/compaction.c:2513 [inline]
try_to_compact_pages+0x317/0x840 mm/compaction.c:2579
__alloc_pages_direct_compact+0x61/0x330 mm/page_alloc.c:4357
__alloc_pages_slowpath+0x2aa/0xbf0 mm/page_alloc.c:4941
__alloc_pages+0x25b/0x320 mm/page_alloc.c:5388
alloc_pages+0x382/0x3d0
__get_free_pages+0x8/0x30 mm/page_alloc.c:5412
io_mem_alloc fs/io_uring.c:8655 [inline]
io_allocate_scq_urings fs/io_uring.c:10052 [inline]
io_uring_create+0x944/0x1980 fs/io_uring.c:10188
io_uring_setup fs/io_uring.c:10278 [inline]
__do_sys_io_uring_setup fs/io_uring.c:10284 [inline]
__se_sys_io_uring_setup fs/io_uring.c:10281 [inline]
__x64_sys_io_uring_setup+0xf3/0x130 fs/io_uring.c:10281
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x44/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff88823fffad90 of 8 bytes by task 17401 on cpu 0:
update_cached_migrate mm/compaction.c:431 [inline]
isolate_migratepages mm/compaction.c:1919 [inline]
compact_zone+0x1425/0x1ce0 mm/compaction.c:2370
compact_zone_order mm/compaction.c:2513 [inline]
try_to_compact_pages+0x317/0x840 mm/compaction.c:2579
__alloc_pages_direct_compact+0x61/0x330 mm/page_alloc.c:4357
__alloc_pages_slowpath+0x5e4/0xbf0 mm/page_alloc.c:5023
__alloc_pages+0x25b/0x320 mm/page_alloc.c:5388
alloc_pages+0x382/0x3d0
__get_free_pages+0x8/0x30 mm/page_alloc.c:5412
io_mem_alloc fs/io_uring.c:8655 [inline]
io_allocate_scq_urings fs/io_uring.c:10052 [inline]
io_uring_create+0x944/0x1980 fs/io_uring.c:10188
io_uring_setup fs/io_uring.c:10278 [inline]
__do_sys_io_uring_setup fs/io_uring.c:10284 [inline]
__se_sys_io_uring_setup fs/io_uring.c:10281 [inline]
__x64_sys_io_uring_setup+0xf3/0x130 fs/io_uring.c:10281
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x44/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x0000000000231200 -> 0x0000000000231c00

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 17401 Comm: syz-executor.0 Tainted: G W 5.14.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.