KCSAN: data-race in __ext4_update_other_inode_time / inode_io_list_del

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: b6505459 Linux 5.10-rc6
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=12423d79500000
kernel config: https://syzkaller.appspot.com/x/.config?x=c949fed53798f819
dashboard link: https://syzkaller.appspot.com/bug?extid=5a3c6a9f3af55e08000a
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+5a3c6a...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in __ext4_update_other_inode_time / inode_io_list_del

read-write to 0xffff88800c079838 of 8 bytes by task 12849 on cpu 1:
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
do_unlinkat+0x2c9/0x4d0 fs/namei.c:3903
__do_sys_unlink fs/namei.c:3943 [inline]
__se_sys_unlink fs/namei.c:3941 [inline]
__x64_sys_unlink+0x2c/0x30 fs/namei.c:3941
do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff88800c079838 of 8 bytes by task 18441 on cpu 0:
__ext4_update_other_inode_time+0x45/0x550 fs/ext4/inode.c:4955
ext4_update_other_inodes_time fs/ext4/inode.c:5002 [inline]
ext4_do_update_inode fs/ext4/inode.c:5131 [inline]
ext4_mark_iloc_dirty+0x1286/0x1650 fs/ext4/inode.c:5712
__ext4_mark_inode_dirty+0x450/0x610 fs/ext4/inode.c:5906
ext4_dirty_inode+0xa6/0xc0 fs/ext4/inode.c:5942
__mark_inode_dirty+0x74/0x740 fs/fs-writeback.c:2260
mark_inode_dirty include/linux/fs.h:2183 [inline]
generic_write_end+0x15e/0x250 fs/buffer.c:2202
ext4_da_write_end+0x59b/0x760 fs/ext4/inode.c:3102
generic_perform_write+0x23e/0x3a0 mm/filemap.c:3340
ext4_buffered_write_iter+0x2e5/0x3d0 fs/ext4/file.c:270
ext4_file_write_iter+0x45e/0x1090 fs/ext4/file.c:503
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: 0 PID: 18441 Comm: syz-executor.4 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.