KCSAN: data-race in isolate_migratepages_block / isolate_migratepages_block (3)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 0477e928 Linux 5.10-rc7
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=10bc3f3d500000
kernel config: https://syzkaller.appspot.com/x/.config?x=329e76890d0bf5c3
dashboard link: https://syzkaller.appspot.com/bug?extid=2b92826e21d4cff38c09
compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project.git 913f6005669cfb590c99865a90bc51ed0983d09d)
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+2b9282...@syzkaller.appspotmail.com

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

write to 0xffff88823fff9290 of 8 bytes by task 13550 on cpu 0:
update_cached_migrate mm/compaction.c:435 [inline]
isolate_migratepages_block+0x15fc/0x1830 mm/compaction.c:1086
isolate_migratepages mm/compaction.c:1852 [inline]
compact_zone+0x1476/0x1d30 mm/compaction.c:2294
compact_node+0x128/0x1e0 mm/compaction.c:2594
compact_nodes mm/compaction.c:2610 [inline]
sysctl_compaction_handler+0x47/0x90 mm/compaction.c:2631
proc_sys_call_handler+0x329/0x4e0 fs/proc/proc_sysctl.c:591
proc_sys_write+0x1e/0x30 fs/proc/proc_sysctl.c:617
call_write_iter include/linux/fs.h:1903 [inline]
new_sync_write fs/read_write.c:518 [inline]
vfs_write+0x6d4/0x7c0 fs/read_write.c:605
ksys_write+0xce/0x180 fs/read_write.c:658
__do_sys_write fs/read_write.c:670 [inline]
__se_sys_write fs/read_write.c:667 [inline]
__x64_sys_write+0x3e/0x50 fs/read_write.c:667
do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff88823fff9290 of 8 bytes by task 13567 on cpu 1:
update_cached_migrate mm/compaction.c:434 [inline]
isolate_migratepages_block+0x15d8/0x1830 mm/compaction.c:1086
isolate_migratepages mm/compaction.c:1852 [inline]
compact_zone+0x1476/0x1d30 mm/compaction.c:2294
compact_node+0x128/0x1e0 mm/compaction.c:2594
compact_nodes mm/compaction.c:2610 [inline]
sysctl_compaction_handler+0x47/0x90 mm/compaction.c:2631
proc_sys_call_handler+0x329/0x4e0 fs/proc/proc_sysctl.c:591
proc_sys_write+0x1e/0x30 fs/proc/proc_sysctl.c:617
call_write_iter include/linux/fs.h:1903 [inline]
new_sync_write fs/read_write.c:518 [inline]
vfs_write+0x6d4/0x7c0 fs/read_write.c:605
ksys_write+0xce/0x180 fs/read_write.c:658
__do_sys_write fs/read_write.c:670 [inline]
__se_sys_write fs/read_write.c:667 [inline]
__x64_sys_write+0x3e/0x50 fs/read_write.c:667
do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 13567 Comm: syz-executor.0 Not tainted 5.10.0-rc7-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.