[moderation] [mm?] KCSAN: data-race in generic_fillattr / shmem_symlink (4)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 7cb1b4663150 Merge tag 'locking_urgent_for_v6.13_rc3' of g..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=145ac544580000
kernel config: https://syzkaller.appspot.com/x/.config?x=1fe4854f351e948c
dashboard link: https://syzkaller.appspot.com/bug?extid=e9c3b6fa2c18c2de97ae
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
CC: [ak...@linux-foundation.org hu...@google.com linux-...@vger.kernel.org linu...@kvack.org]

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/b3832791ba25/disk-7cb1b466.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/3a919028f09b/vmlinux-7cb1b466.xz
kernel image: https://storage.googleapis.com/syzbot-assets/0b507758552c/bzImage-7cb1b466.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+e9c3b6...@syzkaller.appspotmail.com

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

write to 0xffff888102023544 of 4 bytes by task 3287 on cpu 1:
inode_set_mtime_to_ts include/linux/fs.h:1648 [inline]
shmem_symlink+0x349/0x3a0 mm/shmem.c:3958
vfs_symlink+0xca/0x1d0 fs/namei.c:4669
do_symlinkat+0xdf/0x350 fs/namei.c:4695
__do_sys_symlink fs/namei.c:4716 [inline]
__se_sys_symlink fs/namei.c:4714 [inline]
__x64_sys_symlink+0x50/0x60 fs/namei.c:4714
x64_sys_call+0x28b0/0x2dc0 arch/x86/include/generated/asm/syscalls_64.h:89
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 0xffff888102023544 of 4 bytes by task 3752 on cpu 0:
inode_get_mtime_nsec include/linux/fs.h:1634 [inline]
inode_get_mtime include/linux/fs.h:1640 [inline]
generic_fillattr+0x205/0x330 fs/stat.c:102
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: 0x36945445 -> 0x39de29c8

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 3752 Comm: udevd Not tainted 6.13.0-rc2-syzkaller-00018-g7cb1b4663150 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
==================================================================
udevd[3752]: inotify_add_watch(7, /dev/loop2p1, 10) failed: No such file or directory
udevd[3752]: inotify_add_watch(7, /dev/loop2p2, 10) failed: No such file or directory


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[syzbot]

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