syzbot


KCSAN: data-race in copy_process / free_pid (14)

Status: moderation: reported on 2025/01/04 00:52
Subsystems: kernel
[Documentation on labels]
Reported-by: syzbot+fab52e3459fa2f95df57@syzkaller.appspotmail.com
First crash: 11d, last: 11d
Similar bugs (13)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in copy_process / free_pid (8) kernel 1 768d 768d 0/28 auto-obsoleted due to no activity on 2023/01/17 03:08
upstream KCSAN: data-race in copy_process / free_pid (11) kernel 1 234d 234d 0/28 auto-obsoleted due to no activity on 2024/06/30 01:30
upstream KCSAN: data-race in copy_process / free_pid kernel 1 1860d 1860d 0/28 auto-closed as invalid on 2020/02/20 19:37
upstream KCSAN: data-race in copy_process / free_pid (10) kernel 23 273d 402d 0/28 auto-obsoleted due to no activity on 2024/05/21 14:09
upstream KCSAN: data-race in copy_process / free_pid (9) kernel 12 517d 602d 0/28 auto-obsoleted due to no activity on 2023/09/21 05:02
upstream KCSAN: data-race in copy_process / free_pid (6) kernel 2 959d 962d 0/28 auto-closed as invalid on 2022/07/06 07:38
upstream KCSAN: data-race in copy_process / free_pid (4) kernel 1 1263d 1263d 0/28 auto-closed as invalid on 2021/09/04 11:26
upstream KCSAN: data-race in copy_process / free_pid (5) kernel 32 1099d 1218d 0/28 auto-closed as invalid on 2022/02/15 18:33
upstream KCSAN: data-race in copy_process / free_pid (2) kasan 1 1775d 1775d 0/28 auto-closed as invalid on 2020/05/15 22:36
upstream KCSAN: data-race in copy_process / free_pid (7) kernel 4 858d 910d 0/28 auto-obsoleted due to no activity on 2022/10/14 18:22
upstream KCSAN: data-race in copy_process / free_pid (13) kernel 6 89d 123d 0/28 auto-obsoleted due to no activity on 2024/11/22 02:42
upstream KCSAN: data-race in copy_process / free_pid (3) kernel 1 1454d 1454d 0/28 auto-closed as invalid on 2021/02/26 04:07
upstream KCSAN: data-race in copy_process / free_pid (12) kernel 1 192d 192d 0/28 auto-obsoleted due to no activity on 2024/08/11 08:23

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

read-write to 0xffffffff8665d9f8 of 4 bytes by task 11702 on cpu 1:
 free_pid+0x80/0x170 kernel/pid.c:143
 copy_process+0x1213/0x1f90 kernel/fork.c:2644
 kernel_clone+0x167/0x5e0 kernel/fork.c:2806
 __do_sys_clone kernel/fork.c:2949 [inline]
 __se_sys_clone kernel/fork.c:2933 [inline]
 __x64_sys_clone+0xe8/0x120 kernel/fork.c:2933
 x64_sys_call+0x2d7e/0x2dc0 arch/x86/include/generated/asm/syscalls_64.h:57
 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 0xffffffff8665d9f8 of 4 bytes by task 7608 on cpu 0:
 copy_process+0x1799/0x1f90 kernel/fork.c:2549
 kernel_clone+0x167/0x5e0 kernel/fork.c:2806
 user_mode_thread+0x7d/0xb0 kernel/fork.c:2884
 call_usermodehelper_exec_sync kernel/umh.c:132 [inline]
 call_usermodehelper_exec_work+0x7a/0x150 kernel/umh.c:163
 process_one_work kernel/workqueue.c:3229 [inline]
 process_scheduled_works+0x483/0x9a0 kernel/workqueue.c:3310
 worker_thread+0x51d/0x6f0 kernel/workqueue.c:3391
 kthread+0x1d1/0x210 kernel/kthread.c:389
 ret_from_fork+0x4b/0x60 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

value changed: 0x80000116 -> 0x80000115

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 7608 Comm: kworker/u8:56 Not tainted 6.13.0-rc5-syzkaller-00161-g63676eefb7a0 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Workqueue: events_unbound call_usermodehelper_exec_work
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/01/04 00:51 upstream 63676eefb7a0 f3558dbf .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in copy_process / free_pid
* Struck through repros no longer work on HEAD.