[moderation] [fs?] KCSAN: data-race in generic_fillattr / inode_set_ctime_to_ts

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 7503345ac5f5 Merge tag 'block-6.13-20241207' of git://git...
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1293f0f8580000
kernel config: https://syzkaller.appspot.com/x/.config?x=ff022027cd3a0001
dashboard link: https://syzkaller.appspot.com/bug?extid=29f67f1a6d82e4dae6fd
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
CC: [bra...@kernel.org ja...@suse.cz 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/53f05416b2ee/disk-7503345a.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/3d8626fb4628/vmlinux-7503345a.xz
kernel image: https://storage.googleapis.com/syzbot-assets/105f2cfed0e4/bzImage-7503345a.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+29f67f...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in generic_fillattr / inode_set_ctime_to_ts

write to 0xffff88810480e3d8 of 4 bytes by task 3289 on cpu 0:
inode_set_ctime_to_ts+0x85/0x180 fs/inode.c:2716
inode_set_ctime_current+0x1b7/0x7a0 fs/inode.c:2779
shmem_xattr_handler_set+0x1a9/0x220 mm/shmem.c:4163
__vfs_setxattr+0x2e5/0x310 fs/xattr.c:200
__vfs_setxattr_noperm+0xed/0x420 fs/xattr.c:234
__vfs_setxattr_locked+0x1af/0x1d0 fs/xattr.c:295
vfs_setxattr+0x140/0x290 fs/xattr.c:321
do_setxattr fs/xattr.c:636 [inline]
filename_setxattr+0x198/0x2a0 fs/xattr.c:665
path_setxattrat+0x284/0x310 fs/xattr.c:713
__do_sys_lsetxattr fs/xattr.c:754 [inline]
__se_sys_lsetxattr fs/xattr.c:750 [inline]
__x64_sys_lsetxattr+0x71/0x90 fs/xattr.c:750
x64_sys_call+0x29c8/0x2dc0 arch/x86/include/generated/asm/syscalls_64.h:190
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff88810480e3d8 of 4 bytes by task 3511 on cpu 1:
inode_get_ctime_nsec include/linux/fs.h:1678 [inline]
inode_get_ctime include/linux/fs.h:1684 [inline]
generic_fillattr+0x1c9/0x330 fs/stat.c:101
shmem_getattr+0x17b/0x200 mm/shmem.c:1177
vfs_getattr_nosec fs/stat.c:208 [inline]
vfs_getattr fs/stat.c:246 [inline]
vfs_statx_path+0x171/0x2d0 fs/stat.c:283
vfs_statx+0xe1/0x170 fs/stat.c:347
vfs_fstatat fs/stat.c:366 [inline]
__do_sys_newfstatat fs/stat.c:530 [inline]
__se_sys_newfstatat+0xdc/0x300 fs/stat.c:524
__x64_sys_newfstatat+0x55/0x70 fs/stat.c:524
x64_sys_call+0x236d/0x2dc0 arch/x86/include/generated/asm/syscalls_64.h:263
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x30fdc05a -> 0x333e5a92

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 3511 Comm: udevd Not tainted 6.13.0-rc1-syzkaller-00337-g7503345ac5f5 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
==================================================================


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title

If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)

If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup

[syzbot]

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