KCSAN: data-race in fuse_set_nowrite / fuse_writepage_end

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 3bb61aa6 Merge tag 'arm64-fixes' of git://git.kernel.org/p..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1503d44d500000
kernel config: https://syzkaller.appspot.com/x/.config?x=c949fed53798f819
dashboard link: https://syzkaller.appspot.com/bug?extid=f3667834c650c6dfee05
compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project.git 913f6005669cfb590c99865a90bc51ed0983d09d)
CC: [linux-...@vger.kernel.org linux-...@vger.kernel.org mik...@szeredi.hu]

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+f36678...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in fuse_set_nowrite / fuse_writepage_end

read-write to 0xffff88810d843678 of 4 bytes by task 28459 on cpu 0:
fuse_writepage_end+0x43d/0x6f0 fs/fuse/file.c:1783
fuse_request_end+0x764/0x7a0 fs/fuse/dev.c:332
end_requests fs/fuse/dev.c:2067 [inline]
fuse_abort_conn+0xac5/0xb20 fs/fuse/dev.c:2162
fuse_dev_release+0x2b6/0x300 fs/fuse/dev.c:2197
__fput+0x243/0x4d0 fs/file_table.c:281
____fput+0x11/0x20 fs/file_table.c:314
task_work_run+0x8e/0x110 kernel/task_work.c:151
tracehook_notify_resume include/linux/tracehook.h:188 [inline]
exit_to_user_mode_loop kernel/entry/common.c:164 [inline]
exit_to_user_mode_prepare+0x13c/0x170 kernel/entry/common.c:191
syscall_exit_to_user_mode+0x16/0x30 kernel/entry/common.c:266
do_syscall_64+0x45/0x80 arch/x86/entry/common.c:56
entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff88810d843678 of 4 bytes by task 28468 on cpu 1:
fuse_set_nowrite+0x12d/0x180 fs/fuse/dir.c:1487
fuse_sync_writes fs/fuse/file.c:453 [inline]
fuse_fsync+0xf4/0x2b0 fs/fuse/file.c:552
vfs_fsync_range+0x107/0x120 fs/sync.c:200
generic_write_sync include/linux/fs.h:2739 [inline]
generic_file_write_iter+0x103/0x130 mm/filemap.c:3494
fuse_cache_write_iter fs/fuse/file.c:1271 [inline]
fuse_file_write_iter+0x359/0x760 fs/fuse/file.c:1583
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: 28468 Comm: syz-executor.5 Not tainted 5.10.0-rc6-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.