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KCSAN: data-race in generic_fillattr / inode_set_ctime_to_ts (2)

Status: moderation: reported on 2025/07/06 03:23
Subsystems: fs
[Documentation on labels]
Reported-by: syzbot+ea3b255f5f0b8f739316@syzkaller.appspotmail.com
First crash: 12d, last: 19h54m
Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in generic_fillattr / inode_set_ctime_to_ts fs 6 5 82d 221d 0/29 auto-obsoleted due to no activity on 2025/06/21 18:02

Sample crash report:
==================================================================
BUG: KCSAN: data-race in generic_fillattr / inode_set_ctime_to_ts

write to 0xffff888104241268 of 4 bytes by task 3299 on cpu 1:
 inode_set_ctime_to_ts+0x84/0x170 fs/inode.c:2668
 inode_set_ctime_current+0x1d6/0x770 fs/inode.c:2731
 shmem_symlink+0x36b/0x3d0 mm/shmem.c:4134
 vfs_symlink+0xd4/0x1e0 fs/namei.c:4739
 do_symlinkat+0xc7/0x3c0 fs/namei.c:4765
 __do_sys_symlink fs/namei.c:4786 [inline]
 __se_sys_symlink fs/namei.c:4784 [inline]
 __x64_sys_symlink+0x50/0x60 fs/namei.c:4784
 x64_sys_call+0x2d8d/0x2fb0 arch/x86/include/generated/asm/syscalls_64.h:89
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888104241268 of 4 bytes by task 3292 on cpu 0:
 inode_get_ctime_nsec include/linux/fs.h:1748 [inline]
 inode_get_ctime include/linux/fs.h:1754 [inline]
 generic_fillattr+0x1d1/0x340 fs/stat.c:101
 shmem_getattr+0x181/0x200 mm/shmem.c:1262
 vfs_getattr_nosec+0x146/0x1e0 fs/stat.c:213
 vfs_getattr fs/stat.c:262 [inline]
 vfs_statx_path fs/stat.c:299 [inline]
 vfs_statx+0x113/0x390 fs/stat.c:356
 vfs_fstatat+0x115/0x170 fs/stat.c:375
 __do_sys_newfstatat fs/stat.c:542 [inline]
 __se_sys_newfstatat+0x55/0x260 fs/stat.c:536
 __x64_sys_newfstatat+0x55/0x70 fs/stat.c:536
 x64_sys_call+0x2c22/0x2fb0 arch/x86/include/generated/asm/syscalls_64.h:263
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x38b09cba -> 0x392b0bae

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 3292 Comm: udevd Not tainted 6.16.0-rc6-syzkaller-00037-ge2291551827f #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
==================================================================

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/07/17 09:53 upstream e2291551827f 44f8051e .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in generic_fillattr / inode_set_ctime_to_ts
2025/07/06 03:22 upstream 05df91921da6 4f67c4ae .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in generic_fillattr / inode_set_ctime_to_ts
* Struck through repros no longer work on HEAD.