syzbot


KCSAN: data-race in inode_update_timestamps / inode_update_timestamps (4)

Status: moderation: reported on 2025/07/14 10:05
Subsystems: fs
[Documentation on labels]
Reported-by: syzbot+1778e7de757c7b8ee0f5@syzkaller.appspotmail.com
First crash: 14d, last: 14d
Similar bugs (3)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in inode_update_timestamps / inode_update_timestamps ext4 6 130 494d 597d 0/29 auto-obsoleted due to no activity on 2024/04/18 13:35
upstream KCSAN: data-race in inode_update_timestamps / inode_update_timestamps (3) fs 6 9 142d 295d 0/29 auto-obsoleted due to no activity on 2025/05/03 00:27
upstream KCSAN: data-race in inode_update_timestamps / inode_update_timestamps (2) ext4 6 9 338d 439d 0/29 auto-obsoleted due to no activity on 2024/09/28 05:23

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

write to 0xffff888119b349ac of 4 bytes by task 861 on cpu 0:
 inode_set_mtime_to_ts include/linux/fs.h:1718 [inline]
 inode_update_timestamps+0x147/0x270 fs/inode.c:2022
 generic_update_time fs/inode.c:2057 [inline]
 inode_update_time fs/inode.c:2077 [inline]
 __file_update_time fs/inode.c:2305 [inline]
 file_update_time+0x20e/0x2b0 fs/inode.c:2335
 fault_dirty_shared_page+0xd9/0x3c0 mm/memory.c:3420
 do_shared_fault mm/memory.c:5682 [inline]
 do_fault mm/memory.c:5728 [inline]
 do_pte_missing mm/memory.c:4251 [inline]
 handle_pte_fault mm/memory.c:6069 [inline]
 __handle_mm_fault mm/memory.c:6212 [inline]
 handle_mm_fault+0x165d/0x2be0 mm/memory.c:6381
 do_user_addr_fault+0x636/0x1090 arch/x86/mm/fault.c:1336
 handle_page_fault arch/x86/mm/fault.c:1476 [inline]
 exc_page_fault+0x62/0xa0 arch/x86/mm/fault.c:1532
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623

read to 0xffff888119b349ac of 4 bytes by task 862 on cpu 1:
 inode_get_mtime_nsec include/linux/fs.h:1704 [inline]
 inode_get_mtime include/linux/fs.h:1710 [inline]
 inode_update_timestamps+0x74/0x270 fs/inode.c:2016
 generic_update_time fs/inode.c:2057 [inline]
 inode_update_time fs/inode.c:2077 [inline]
 __file_update_time fs/inode.c:2305 [inline]
 file_update_time+0x20e/0x2b0 fs/inode.c:2335
 fault_dirty_shared_page+0xd9/0x3c0 mm/memory.c:3420
 do_shared_fault mm/memory.c:5682 [inline]
 do_fault mm/memory.c:5728 [inline]
 do_pte_missing mm/memory.c:4251 [inline]
 handle_pte_fault mm/memory.c:6069 [inline]
 __handle_mm_fault mm/memory.c:6212 [inline]
 handle_mm_fault+0x165d/0x2be0 mm/memory.c:6381
 faultin_page mm/gup.c:1186 [inline]
 __get_user_pages+0x1036/0x1fb0 mm/gup.c:1488
 __get_user_pages_locked mm/gup.c:1754 [inline]
 faultin_page_range+0x10f/0x5b0 mm/gup.c:1978
 madvise_populate mm/madvise.c:974 [inline]
 madvise_do_behavior+0x120/0x1f20 mm/madvise.c:1731
 do_madvise+0x103/0x190 mm/madvise.c:1826
 __do_sys_madvise mm/madvise.c:1835 [inline]
 __se_sys_madvise mm/madvise.c:1833 [inline]
 __x64_sys_madvise+0x64/0x80 mm/madvise.c:1833
 x64_sys_call+0x2455/0x2fb0 arch/x86/include/generated/asm/syscalls_64.h:29
 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: 0x1c03a8b0 -> 0x1c9c3f30

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 862 Comm: syz.7.10780 Not tainted 6.16.0-rc6-syzkaller #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/07/14 10:05 upstream 347e9f5043c8 3cda49cf .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in inode_update_timestamps / inode_update_timestamps
* Struck through repros no longer work on HEAD.