KCSAN: data-race in __ext4_update_other_inode_time / __mark_inode_dirty

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 3cea11cd Linux 5.10-rc2
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=11defa8a500000
kernel config: https://syzkaller.appspot.com/x/.config?x=76dfc991796328d4
dashboard link: https://syzkaller.appspot.com/bug?extid=b21fe66a80c277eb3330
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+b21fe6...@syzkaller.appspotmail.com

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

write to 0xffff88800ef217f8 of 8 bytes by task 2770 on cpu 1:
__mark_inode_dirty+0x212/0x740 fs/fs-writeback.c:2290
mark_inode_dirty include/linux/fs.h:2167 [inline]
ext4_setattr+0x3ad/0xf60 fs/ext4/inode.c:5502
notify_change+0x7b3/0xa50 fs/attr.c:336
do_truncate+0xe0/0x120 fs/open.c:64
handle_truncate fs/namei.c:2910 [inline]
do_open fs/namei.c:3256 [inline]
path_openat+0x1a37/0x20a0 fs/namei.c:3369
do_filp_open+0xbd/0x1d0 fs/namei.c:3396
do_sys_openat2+0xa3/0x240 fs/open.c:1168
do_sys_open fs/open.c:1184 [inline]
__do_sys_creat fs/open.c:1258 [inline]
__se_sys_creat fs/open.c:1252 [inline]
__x64_sys_creat+0x62/0x80 fs/open.c:1252
do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff88800ef217f8 of 8 bytes by task 2769 on cpu 0:
__ext4_update_other_inode_time+0x45/0x550 fs/ext4/inode.c:4954
ext4_update_other_inodes_time fs/ext4/inode.c:5001 [inline]
ext4_do_update_inode fs/ext4/inode.c:5130 [inline]
ext4_mark_iloc_dirty+0x1286/0x1650 fs/ext4/inode.c:5711
__ext4_mark_inode_dirty+0x450/0x610 fs/ext4/inode.c:5905
ext4_ext_tree_init+0x7e/0x90 fs/ext4/extents.c:828
__ext4_new_inode+0x2a8d/0x3070 fs/ext4/ialloc.c:1326
ext4_symlink+0x2bc/0x770 fs/ext4/namei.c:3341
vfs_symlink+0x216/0x2d0 fs/namei.c:3960
do_symlinkat+0xee/0x280 fs/namei.c:3987
__do_sys_symlink fs/namei.c:4006 [inline]
__se_sys_symlink fs/namei.c:4004 [inline]
__x64_sys_symlink+0x32/0x40 fs/namei.c:4004
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: 2769 Comm: syz-executor.5 Not tainted 5.10.0-rc2-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.