KCSAN: data-race in __writeback_single_inode / inode_io_list_del

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 27bba9c5 Merge tag 'scsi-fixes' of git://git.kernel.org/pu..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1455d899500000
kernel config: https://syzkaller.appspot.com/x/.config?x=73fc125ff8990ab9
dashboard link: https://syzkaller.appspot.com/bug?extid=909b30f513c13ccb9e7e
compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project.git 913f6005669cfb590c99865a90bc51ed0983d09d)
CC: [linux-...@vger.kernel.org linux-...@vger.kernel.org vi...@zeniv.linux.org.uk]

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+909b30...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in __writeback_single_inode / inode_io_list_del

read-write to 0xffff88800997a6b8 of 8 bytes by task 8463 on cpu 0:
inode_io_list_del_locked fs/fs-writeback.c:148 [inline]
inode_io_list_del+0x91/0x240 fs/fs-writeback.c:1127
evict+0xac/0x470 fs/inode.c:565
iput_final fs/inode.c:1654 [inline]
iput+0x421/0x510 fs/inode.c:1680
dentry_unlink_inode+0x1f3/0x210 fs/dcache.c:374
d_delete+0x70/0xa0 fs/dcache.c:2470
vfs_rmdir+0x271/0x290 fs/namei.c:3727
do_rmdir+0x16e/0x300 fs/namei.c:3774
__do_sys_rmdir fs/namei.c:3792 [inline]
__se_sys_rmdir fs/namei.c:3790 [inline]
__x64_sys_rmdir+0x2c/0x30 fs/namei.c:3790
do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff88800997a6b8 of 8 bytes by task 304 on cpu 1:
__writeback_single_inode+0x45/0x560 fs/fs-writeback.c:1457
writeback_sb_inodes+0x6a0/0x1020 fs/fs-writeback.c:1721
wb_writeback+0x27d/0x660 fs/fs-writeback.c:1894
wb_do_writeback+0x101/0x5d0 fs/fs-writeback.c:2039
wb_workfn+0xb8/0x410 fs/fs-writeback.c:2080
process_one_work+0x3e1/0x950 kernel/workqueue.c:2272
worker_thread+0x635/0xb90 kernel/workqueue.c:2418
kthread+0x1fa/0x220 kernel/kthread.c:292
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 304 Comm: kworker/u4:3 Not tainted 5.10.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: writeback wb_workfn (flush-8:0)
==================================================================


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[syzbot]

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