[moderation] [fs?] KCSAN: data-race in generic_fillattr / setattr_copy (3)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 92514ef226f5 Merge tag 'for-6.14-rc1-tag' of git://git.ker..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=125d41b0580000
kernel config: https://syzkaller.appspot.com/x/.config?x=9e757e3762bd630b
dashboard link: https://syzkaller.appspot.com/bug?extid=37a45749dbc529a6cb1c
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/51c17e48f9e6/disk-92514ef2.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/886793feee1e/vmlinux-92514ef2.xz
kernel image: https://storage.googleapis.com/syzbot-assets/237330dbc118/bzImage-92514ef2.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+37a457...@syzkaller.appspotmail.com

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

write to 0xffff88812358b82c of 4 bytes by task 4547 on cpu 0:
inode_set_mtime_to_ts include/linux/fs.h:1696 [inline]
setattr_copy+0x2c8/0x4a0 fs/attr.c:361
shmem_setattr+0x532/0x830 mm/shmem.c:1330
notify_change+0x85c/0x8e0 fs/attr.c:552
vfs_utimes+0x2c6/0x3e0 fs/utimes.c:66
do_utimes_path fs/utimes.c:99 [inline]
do_utimes+0x149/0x1f0 fs/utimes.c:140
__do_sys_utimensat fs/utimes.c:159 [inline]
__se_sys_utimensat fs/utimes.c:143 [inline]
__x64_sys_utimensat+0xc6/0x170 fs/utimes.c:143
x64_sys_call+0x272a/0x2dc0 arch/x86/include/generated/asm/syscalls_64.h:281
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 0xffff88812358b82c of 4 bytes by task 3699 on cpu 1:
inode_get_mtime_nsec include/linux/fs.h:1682 [inline]
inode_get_mtime include/linux/fs.h:1688 [inline]
generic_fillattr+0x205/0x330 fs/stat.c:102
shmem_getattr+0x17b/0x200 mm/shmem.c:1249
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: 0x31dca96c -> 0x34b81a6f

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 3699 Comm: udevd Not tainted 6.14.0-rc1-syzkaller-00034-g92514ef226f5 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
==================================================================


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[syzbot]

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