KCSAN: data-race in atime_needs_update / inode_set_ctime_current

Status: moderation: reported on 2023/12/09 00:00
Subsystems: fs
Labels: prio:low
[Documentation on labels]
Reported-by: syzbot+55e393c8d287963ea4b1@syzkaller.appspotmail.com
First crash: 1077d, last: 2d04h
✨ AI Jobs (4)
ID Workflow Result Correct Bug Created Started Finished Revision
d55b8950 assessment-security DenialOfService: ❌ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ✅ UserNamespace: ✅ VMGuestTrigger: ❌ VMHostTrigger: ❌ KCSAN: data-race in atime_needs_update / inode_set_ctime_current 2026/05/19 04:16 2026/05/19 04:16 2026/05/19 04:17 9f74d399
6dfd215d repro KCSAN: data-race in atime_needs_update / inode_set_ctime_current 2026/03/08 15:33 2026/03/08 15:33 2026/03/08 15:39 31e9c887
6502007c assessment-kcsan Benign: ✅ Confident: ✅ KCSAN: data-race in atime_needs_update / inode_set_ctime_current 2026/02/25 00:13 2026/02/25 00:13 2026/02/25 00:16 305c0ec5
da4160ac assessment-kcsan 💥 KCSAN: data-race in atime_needs_update / inode_set_ctime_current 2026/01/10 07:26 2026/01/10 07:26 2026/01/10 07:26 75199160

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

write to 0xffff88811c1d1138 of 8 bytes by task 15916 on cpu 1:
 inode_set_ctime_current+0x600/0x8e0 fs/inode.c:2932
 __simple_unlink fs/libfs.c:792 [inline]
 simple_unlink+0x2d/0x80 fs/libfs.c:807
 shmem_unlink+0x12d/0x140 mm/shmem.c:3927
 vfs_unlink+0x1c3/0x490 fs/namei.c:5515
 filename_unlinkat+0x1dc/0x410 fs/namei.c:5585
 __do_sys_unlink fs/namei.c:5620 [inline]
 __se_sys_unlink+0x2b/0xe0 fs/namei.c:5617
 __x64_sys_unlink+0x1f/0x30 fs/namei.c:5617
 x64_sys_call+0x2eb6/0x3020 arch/x86/include/generated/asm/syscalls_64.h:88
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x136/0x3c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff88811c1d1138 of 8 bytes by task 2981 on cpu 0:
 inode_get_ctime_sec include/linux/fs.h:1680 [inline]
 inode_get_ctime include/linux/fs.h:1690 [inline]
 relatime_need_update fs/inode.c:2133 [inline]
 atime_needs_update+0x2ef/0x3e0 fs/inode.c:2297
 touch_atime+0x4a/0x300 fs/inode.c:2312
 do_readlinkat+0x137/0x2f0 fs/stat.c:582
 __do_sys_readlink fs/stat.c:605 [inline]
 __se_sys_readlink fs/stat.c:602 [inline]
 __x64_sys_readlink+0x47/0x60 fs/stat.c:602
 x64_sys_call+0x2b51/0x3020 arch/x86/include/generated/asm/syscalls_64.h:90
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x136/0x3c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00000000773596c7 -> 0x00000000773596c9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 2981 Comm: udevd Not tainted syzkaller #0 PREEMPT(lazy) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
==================================================================

Crashes (533):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/10 20:27 upstream d58772d8520c 508909ea .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_set_ctime_current
2026/07/31 03:25 upstream 3708dd948844 aaffb173 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_set_ctime_current
2026/07/30 00:06 upstream fc46aed51f62 6ef5c1e2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_set_ctime_current
2026/07/27 01:01 upstream 4235cb24ec1e 492bab15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_set_ctime_current
2026/07/23 22:50 upstream d326f83e819c 71a13572 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_set_ctime_current
2026/07/23 16:50 upstream 4539944e5151 71a13572 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_set_ctime_current
2026/07/23 10:01 upstream 4539944e5151 881ce5c2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_set_ctime_current
2026/07/18 05:46 upstream 94515f3a7d42 72524a66 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_set_ctime_current
2026/07/16 10:48 upstream 37e2f878a7a6 27a8bd60 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_set_ctime_current
2026/07/12 11:51 upstream 44696aa3a489 d78ea535 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_set_ctime_current
2026/07/10 13:51 upstream a635d6748234 99e64375 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_set_ctime_current
2026/07/04 04:35 upstream 71dfdfb0209b fcece630 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_set_ctime_current
2026/07/01 13:33 upstream 665159e24674 00a5cf1c .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_set_ctime_current
2026/06/30 04:18 upstream dc59e4fea9d8 fff8d0a0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_set_ctime_current
2026/06/21 05:19 upstream 390d73adf896 43bfcdb0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_set_ctime_current
2026/06/13 21:13 upstream 2b07ea76fd28 1d2f3589 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_set_ctime_current
2026/06/11 09:05 upstream 9716c086c8e8 b754d2d8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_set_ctime_current
2026/06/02 14:12 upstream 6f3ed7fec72f 62fe1528 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_set_ctime_current
2026/06/02 06:20 upstream 6f3ed7fec72f 1095583b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_set_ctime_current
2026/05/30 16:56 upstream f5e5d3509bff 6b4a8443 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_set_ctime_current
2026/05/30 07:29 upstream 9215e74f228f 6b4a8443 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_set_ctime_current
2026/05/28 22:25 upstream 8fde5d1d47f6 681715f7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_set_ctime_current
2026/05/25 16:50 upstream e7ae89a0c97c c69befb3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_set_ctime_current
2026/05/25 04:50 upstream 6a97c4d5262d c69befb3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_set_ctime_current
2026/05/22 05:47 upstream 6779b50faa56 70ae9b03 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_set_ctime_current
2026/05/21 17:20 upstream 758c807bb943 e195359d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_set_ctime_current
2026/05/20 06:39 upstream 27fa82620cba 0909d65f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_set_ctime_current
2026/05/18 13:05 upstream 5200f5f493f7 55156e84 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_set_ctime_current
2026/05/17 08:44 upstream 6916d5703ddf de5aae85 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_set_ctime_current
2026/05/14 00:24 upstream e1914add2799 6ccb967e .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_set_ctime_current
2026/05/13 01:20 upstream c21b90f77687 a0949470 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_set_ctime_current
2026/05/11 22:45 upstream 5d6919055dec d168f260 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_set_ctime_current
2026/05/11 04:35 upstream 5d6919055dec 29233ece .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_set_ctime_current
2026/05/09 07:26 upstream 27a26ccfd528 29233ece .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_set_ctime_current
2026/05/06 21:57 upstream 74fe02ce122a 1dddfd3d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_set_ctime_current
2026/05/06 00:50 upstream 9207d47f966b 26da2c66 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_set_ctime_current
2026/05/03 01:23 upstream 66edb901bf87 a0d91488 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_set_ctime_current
2026/04/24 17:21 upstream dd6c438c3e64 1c2b9291 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_set_ctime_current
2026/04/23 02:12 upstream 2a4c0c11c019 b10da5ec .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_set_ctime_current
2026/04/21 11:39 upstream b4e07588e743 3f2e655b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_set_ctime_current
2026/04/19 19:53 upstream faeab166167f 303e2802 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_set_ctime_current
2026/04/18 09:34 upstream 8541d8f725c6 303e2802 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_set_ctime_current
2026/04/17 18:20 upstream 43cfbdda5af6 24ecfc1e .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_set_ctime_current
2026/04/16 14:37 upstream 1d51b370a0f8 4743f87d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_set_ctime_current
2026/04/15 15:43 upstream 1f5ffc672165 c441f497 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_set_ctime_current
2026/03/02 00:10 upstream 39c633261414 43249bac .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_set_ctime_current
2026/02/23 03:09 upstream 6de23f81a5e0 6e7b5511 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_set_ctime_current
2026/01/09 03:24 upstream 79b95d74470d d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_set_ctime_current
2023/12/08 14:09 upstream 5e3f5b81de80 28b24332 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_set_ctime_current
2023/11/20 12:30 upstream 98b1cc82c4af cb976f63 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_set_ctime_current
* Struck through repros no longer work on HEAD.