[moderation] [ext4?] KCSAN: data-race in inode_update_timestamps / inode_update_timestamps

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 9ace34a8e446 Merge tag 'cgroup-for-6.7-rc4-fixes' of git:/..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=11da49b4e80000
kernel config: https://syzkaller.appspot.com/x/.config?x=ac34c1f29a8029df
dashboard link: https://syzkaller.appspot.com/bug?extid=52607d66a8e561f92944
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
CC: [adilger...@dilger.ca bra...@kernel.org linux...@vger.kernel.org linux-...@vger.kernel.org linux-...@vger.kernel.org ty...@mit.edu vi...@zeniv.linux.org.uk]

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/955528ed37c5/disk-9ace34a8.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/ed03c0892611/vmlinux-9ace34a8.xz
kernel image: https://storage.googleapis.com/syzbot-assets/b4d56563956a/bzImage-9ace34a8.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+52607d...@syzkaller.appspotmail.com

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

write to 0xffff8881a0eb5570 of 8 bytes by task 3376 on cpu 1:
inode_set_atime_to_ts include/linux/fs.h:1537 [inline]
inode_update_timestamps+0x4d1/0x560 fs/inode.c:1914
generic_update_time fs/inode.c:1936 [inline]
inode_update_time fs/inode.c:1956 [inline]
touch_atime+0x15c/0x2d0 fs/inode.c:2028
file_accessed include/linux/fs.h:2360 [inline]
iterate_dir+0x2db/0x300 fs/readdir.c:109
__do_sys_getdents64 fs/readdir.c:405 [inline]
__se_sys_getdents64+0x88/0x1a0 fs/readdir.c:390
__x64_sys_getdents64+0x43/0x50 fs/readdir.c:390
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0x44/0x110 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x63/0x6b

read to 0xffff8881a0eb5570 of 8 bytes by task 4590 on cpu 0:
inode_get_atime include/linux/fs.h:1531 [inline]
inode_update_timestamps+0x498/0x560 fs/inode.c:1911
generic_update_time fs/inode.c:1936 [inline]
inode_update_time fs/inode.c:1956 [inline]
touch_atime+0x15c/0x2d0 fs/inode.c:2028
file_accessed include/linux/fs.h:2360 [inline]
iterate_dir+0x2db/0x300 fs/readdir.c:109
__do_sys_getdents64 fs/readdir.c:405 [inline]
__se_sys_getdents64+0x88/0x1a0 fs/readdir.c:390
__x64_sys_getdents64+0x43/0x50 fs/readdir.c:390
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0x44/0x110 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x63/0x6b

value changed: 0x00000000265fc2e7 -> 0x000000002b2476e8

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 4590 Comm: udevd Not tainted 6.7.0-rc4-syzkaller-00039-g9ace34a8e446 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/10/2023
==================================================================
I/O error, dev loop2, sector 0 op 0x0:(READ) flags 0x80700 phys_seg 1 prio class 2
I/O error, dev loop4, sector 0 op 0x0:(READ) flags 0x80700 phys_seg 1 prio class 2
I/O error, dev loop4, sector 0 op 0x0:(READ) flags 0x80700 phys_seg 1 prio class 2


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[syzbot]

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