[moderation] [fs?] KCSAN: data-race in atime_needs_update / inode_set_ctime_current

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 5e3f5b81de80 Merge tag 'net-6.7-rc5' of git://git.kernel.o..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=17328e46e80000
kernel config: https://syzkaller.appspot.com/x/.config?x=ac34c1f29a8029df
dashboard link: https://syzkaller.appspot.com/bug?extid=55e393c8d287963ea4b1
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
CC: [bra...@kernel.org linux-...@vger.kernel.org linux-...@vger.kernel.org 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/8894c209e25f/disk-5e3f5b81.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/42757ce1a7da/vmlinux-5e3f5b81.xz
kernel image: https://storage.googleapis.com/syzbot-assets/a3314e0b4681/bzImage-5e3f5b81.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+55e393...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in atime_needs_update / inode_set_ctime_current

write to 0xffff888130e19590 of 8 bytes by task 24988 on cpu 1:
inode_set_ctime_to_ts include/linux/fs.h:1597 [inline]
inode_set_ctime include/linux/fs.h:1615 [inline]
inode_set_ctime_current+0x16c/0x1d0 fs/inode.c:2550
shmem_unlink+0x114/0x180 mm/shmem.c:3353
vfs_unlink+0x261/0x3e0 fs/namei.c:4318
do_unlinkat+0x236/0x4c0 fs/namei.c:4382
__do_sys_unlink fs/namei.c:4430 [inline]
__se_sys_unlink fs/namei.c:4428 [inline]
__x64_sys_unlink+0x30/0x40 fs/namei.c:4428
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 0xffff888130e19590 of 8 bytes by task 2779 on cpu 0:
inode_get_ctime include/linux/fs.h:1591 [inline]
relatime_need_update fs/inode.c:1856 [inline]
atime_needs_update+0x4c8/0x550 fs/inode.c:1996
touch_atime+0x46/0x2d0 fs/inode.c:2011
do_readlinkat+0x164/0x210 fs/stat.c:505
__do_sys_readlink fs/stat.c:527 [inline]
__se_sys_readlink fs/stat.c:524 [inline]
__x64_sys_readlink+0x47/0x50 fs/stat.c:524
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: 0x00000000298b7ad9 -> 0x000000002e8c7c5a

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 2779 Comm: udevd Tainted: G W 6.7.0-rc4-syzkaller-00111-g5e3f5b81de80 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/10/2023
==================================================================


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