syzbot


KCSAN: data-race in atime_needs_update / inode_update_timestamps

Status: moderation: reported on 2023/12/09 00:01
Subsystems: ext4
[Documentation on labels]
Reported-by: syzbot+874bb8a8db3b21a66b1c@syzkaller.appspotmail.com
First crash: 734d, last: 1d12h

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

write to 0xffff88811a33de04 of 4 bytes by task 4864 on cpu 1:
 inode_set_mtime_to_ts include/linux/fs.h:1721 [inline]
 inode_update_timestamps+0x147/0x270 fs/inode.c:2021
 generic_update_time fs/inode.c:2056 [inline]
 inode_update_time fs/inode.c:2076 [inline]
 __file_update_time fs/inode.c:2304 [inline]
 file_update_time+0x20e/0x2b0 fs/inode.c:2334
 shmem_file_write_iter+0x9c/0xf0 mm/shmem.c:3525
 iter_file_splice_write+0x663/0xa60 fs/splice.c:738
 do_splice_from fs/splice.c:938 [inline]
 direct_splice_actor+0x153/0x2a0 fs/splice.c:1161
 splice_direct_to_actor+0x30f/0x680 fs/splice.c:1105
 do_splice_direct_actor fs/splice.c:1204 [inline]
 do_splice_direct+0xda/0x150 fs/splice.c:1230
 do_sendfile+0x380/0x650 fs/read_write.c:1370
 __do_sys_sendfile64 fs/read_write.c:1431 [inline]
 __se_sys_sendfile64 fs/read_write.c:1417 [inline]
 __x64_sys_sendfile64+0x105/0x150 fs/read_write.c:1417
 x64_sys_call+0x2bb0/0x2ff0 arch/x86/include/generated/asm/syscalls_64.h:41
 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 0xffff88811a33de04 of 4 bytes by task 4855 on cpu 0:
 inode_get_mtime_nsec include/linux/fs.h:1707 [inline]
 inode_get_mtime include/linux/fs.h:1713 [inline]
 relatime_need_update fs/inode.c:1970 [inline]
 atime_needs_update+0x2a8/0x3e0 fs/inode.c:2116
 touch_atime+0x4a/0x340 fs/inode.c:2131
 file_accessed include/linux/fs.h:2663 [inline]
 shmem_file_read_iter+0x477/0x540 mm/shmem.c:3508
 copy_splice_read+0x442/0x660 fs/splice.c:363
 do_splice_read fs/splice.c:981 [inline]
 splice_direct_to_actor+0x290/0x680 fs/splice.c:1086
 do_splice_direct_actor fs/splice.c:1204 [inline]
 do_splice_direct+0xda/0x150 fs/splice.c:1230
 do_sendfile+0x380/0x650 fs/read_write.c:1370
 __do_sys_sendfile64 fs/read_write.c:1431 [inline]
 __se_sys_sendfile64 fs/read_write.c:1417 [inline]
 __x64_sys_sendfile64+0x105/0x150 fs/read_write.c:1417
 x64_sys_call+0x2bb0/0x2ff0 arch/x86/include/generated/asm/syscalls_64.h:41
 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: 0x302811ef -> 0x30c0a872

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 4855 Comm: syz.0.334 Not tainted syzkaller #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
==================================================================

Crashes (347):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/08/31 18:52 upstream 5c3b3264e585 807a3b61 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_update_timestamps
2025/08/31 05:51 upstream c8bc81a52d5a 807a3b61 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_update_timestamps
2025/08/29 23:39 upstream fb679c832b64 807a3b61 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_update_timestamps
2025/08/29 17:53 upstream fb679c832b64 3e1beec6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_update_timestamps
2025/08/27 18:55 upstream 39f90c196721 e12e5ba4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_update_timestamps
2025/08/26 16:54 upstream fab1beda7597 e12e5ba4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_update_timestamps
2025/08/25 16:56 upstream b6add54ba618 bf27483f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_update_timestamps
2025/08/24 16:14 upstream 69fd6b99b8f8 bf27483f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_update_timestamps
2025/08/23 15:34 upstream 6debb6904172 bf27483f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_update_timestamps
2025/08/22 05:14 upstream 3957a5720157 bf27483f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_update_timestamps
2025/08/21 20:08 upstream 068a56e56fa8 3e79b825 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_update_timestamps
2025/08/21 12:01 upstream 068a56e56fa8 0b9605c8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_update_timestamps
2025/08/20 19:49 upstream b19a97d57c15 0b9605c8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_update_timestamps
2025/08/20 02:52 upstream b19a97d57c15 79512909 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_update_timestamps
2025/08/19 01:56 upstream be48bcf004f9 523f460e .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_update_timestamps
2025/08/18 12:15 upstream c17b750b3ad9 1804e95e .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_update_timestamps
2025/08/17 09:07 upstream 99bade344cfa 1804e95e .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_update_timestamps
2025/08/15 04:40 upstream 24ea63ea3877 1804e95e .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_update_timestamps
2025/08/14 14:36 upstream 0cc53520e68b 5d8c2ac2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_update_timestamps
2025/08/10 06:15 upstream 561c80369df0 32a0e5ed .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_update_timestamps
2025/08/08 20:08 upstream 37816488247d 32a0e5ed .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_update_timestamps
2025/08/08 02:20 upstream 6e64f4580381 6a893178 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_update_timestamps
2025/08/05 11:20 upstream 7e161a991ea7 37880f40 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_update_timestamps
2025/08/04 11:23 upstream d2eedaa3909b 7368264b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_update_timestamps
2025/08/04 02:24 upstream 352af6a011d5 7368264b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_update_timestamps
2025/08/03 04:58 upstream 186f3edfdd41 7368264b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_update_timestamps
2025/08/03 04:56 upstream 186f3edfdd41 7368264b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_update_timestamps
2025/08/02 04:23 upstream 0905809b38bd 7368264b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_update_timestamps
2025/07/30 11:38 upstream 4b290aae788e f8f2b4da .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_update_timestamps
2025/07/29 14:43 upstream ae388edd4a8f c4a95487 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_update_timestamps
2025/07/29 05:08 upstream ae388edd4a8f 6654ea9c .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_update_timestamps
2025/07/25 00:40 upstream 94ce1ac2c9b4 fb8f743d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_update_timestamps
2025/07/23 20:08 upstream 01a412d06bc5 e1dd4f22 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_update_timestamps
2025/07/23 05:38 upstream 89be9a83ccf1 e1dd4f22 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_update_timestamps
2025/07/22 15:03 upstream 89be9a83ccf1 8e9d1dc1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_update_timestamps
2025/07/21 04:46 upstream 89be9a83ccf1 7117feec .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_update_timestamps
2025/07/20 01:09 upstream bf61759db409 7117feec .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_update_timestamps
2025/07/12 11:03 upstream 379f604cc3dc 3cda49cf .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_update_timestamps
2025/07/11 13:39 upstream bc9ff192a6c9 3cda49cf .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_update_timestamps
2025/07/05 21:26 upstream 05df91921da6 4f67c4ae .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_update_timestamps
2025/07/03 18:46 upstream 17bbde2e1716 115ceea7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_update_timestamps
2025/06/28 16:54 upstream 67a993863163 fc9d8ee5 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_update_timestamps
2025/06/25 22:02 upstream 92ca6c498a5e 26d77996 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_update_timestamps
2025/06/24 23:16 upstream 78f4e737a53e 26d77996 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_update_timestamps
2025/06/16 04:27 upstream 08215f5486ec 5f4b362d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_update_timestamps
2025/06/09 02:09 upstream 939f15e640f1 4826c28e .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_update_timestamps
2025/06/06 22:26 upstream c0c9379f235d 9fa58bba .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_update_timestamps
2025/06/06 05:22 upstream e271ed52b344 6b6b5f21 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_update_timestamps
2023/12/07 23:46 upstream 9ace34a8e446 28b24332 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_update_timestamps
2023/12/05 19:08 upstream bee0e7762ad2 858d62d1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in atime_needs_update / inode_update_timestamps
* Struck through repros no longer work on HEAD.