[moderation] [fs?] KCSAN: data-race in generic_fillattr / inode_set_ctime_current (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 08a6b55aa0c6 Merge tag 'x86-urgent-2024-06-15' of git://gi..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=118a3fee980000
kernel config: https://syzkaller.appspot.com/x/.config?x=68336ea4b6f4fc09
dashboard link: https://syzkaller.appspot.com/bug?extid=0d36cf3d5d465c77e056
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/45059686fb5e/disk-08a6b55a.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/f6bd1c373f83/vmlinux-08a6b55a.xz
kernel image: https://storage.googleapis.com/syzbot-assets/845417ea3554/bzImage-08a6b55a.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+0d36cf...@syzkaller.appspotmail.com

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

write to 0xffff888104284cc0 of 8 bytes by task 4600 on cpu 1:
inode_set_ctime_to_ts include/linux/fs.h:1617 [inline]
inode_set_ctime_current+0x38/0x50 fs/inode.c:2515
simple_rename_timestamp+0x34/0xd0 fs/libfs.c:799
shmem_rename2+0x284/0x2c0 mm/shmem.c:3486
vfs_rename+0x872/0x9c0 fs/namei.c:4887
do_renameat2+0x732/0xa60 fs/namei.c:5044
__do_sys_rename fs/namei.c:5091 [inline]
__se_sys_rename fs/namei.c:5089 [inline]
__x64_sys_rename+0x5c/0x70 fs/namei.c:5089
x64_sys_call+0x2781/0x2d70 arch/x86/include/generated/asm/syscalls_64.h:83
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 0xffff888104284cc0 of 8 bytes by task 3071 on cpu 0:
inode_get_ctime include/linux/fs.h:1611 [inline]
generic_fillattr+0x1e0/0x2f0 fs/stat.c:62
shmem_getattr+0x17b/0x200 mm/shmem.c:1139
vfs_getattr_nosec fs/stat.c:135 [inline]
vfs_getattr+0x19b/0x1e0 fs/stat.c:176
vfs_statx+0x140/0x320 fs/stat.c:248
vfs_fstatat+0xcd/0x100 fs/stat.c:304
__do_sys_newfstatat fs/stat.c:468 [inline]
__se_sys_newfstatat+0x58/0x260 fs/stat.c:462
__x64_sys_newfstatat+0x55/0x70 fs/stat.c:462
x64_sys_call+0x1451/0x2d70 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: 0x000000002b6537f8 -> 0x000000002bfdce78

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 3071 Comm: udevd Tainted: G W 6.10.0-rc3-syzkaller-00169-g08a6b55aa0c6 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024
==================================================================


---
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