syzbot


KCSAN: data-race in copy_process / copy_process (2)

Status: fixed on 2020/08/01 00:48
Subsystems: kernel
[Documentation on labels]
Reported-by: syzbot+52fced2d288f8ecd2b20@syzkaller.appspotmail.com
Fix commit: c17d1a3a8ee4 fork: annotate data race in copy_process()
First crash: 1636d, last: 1383d
Discussions (1)
Title Replies (including bot) Last reply
[PATCH v2] kernel/fork.c: annotate data races for copy_process 2 (2) 2020/06/23 10:01
Similar bugs (1)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in copy_process / copy_process kasan 1 1644d 1644d 0/26 closed as invalid on 2019/10/18 14:11

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

write to 0xffffffff8927a410 of 4 bytes by task 25 on cpu 0:
 copy_process+0x2e84/0x3300 kernel/fork.c:2298
 _do_fork+0xf1/0x660 kernel/fork.c:2443
 kernel_thread+0x85/0xb0 kernel/fork.c:2531
 call_usermodehelper_exec_work+0x4f/0x1b0 kernel/umh.c:195
 process_one_work+0x3e1/0x9a0 kernel/workqueue.c:2269
 worker_thread+0x665/0xbe0 kernel/workqueue.c:2415
 kthread+0x20d/0x230 kernel/kthread.c:291
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293

read to 0xffffffff8927a410 of 4 bytes by task 3411 on cpu 1:
 copy_process+0xac4/0x3300 kernel/fork.c:1980
 _do_fork+0xf1/0x660 kernel/fork.c:2443
 kernel_thread+0x85/0xb0 kernel/fork.c:2531
 call_usermodehelper_exec_work+0x4f/0x1b0 kernel/umh.c:195
 process_one_work+0x3e1/0x9a0 kernel/workqueue.c:2269
 worker_thread+0x665/0xbe0 kernel/workqueue.c:2415
 kthread+0x20d/0x230 kernel/kthread.c:291
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 3411 Comm: kworker/u4:4 Not tainted 5.8.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events_unbound call_usermodehelper_exec_work
==================================================================

Crashes (294):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2020/07/02 07:51 upstream cd77006e01b3 bed10395 .config console log report ci2-upstream-kcsan-gce
2020/07/02 06:09 upstream cd77006e01b3 bed10395 .config console log report ci2-upstream-kcsan-gce
2020/07/02 03:49 upstream cd77006e01b3 bed10395 .config console log report ci2-upstream-kcsan-gce
2020/07/01 22:47 upstream edb543cfe5db bed10395 .config console log report ci2-upstream-kcsan-gce
2020/07/01 21:43 upstream edb543cfe5db bed10395 .config console log report ci2-upstream-kcsan-gce
2020/07/01 20:12 upstream edb543cfe5db 695ef2dd .config console log report ci2-upstream-kcsan-gce
2020/07/01 18:58 upstream 7c30b859a947 39acb39d .config console log report ci2-upstream-kcsan-gce
2020/07/01 14:09 upstream 7c30b859a947 39acb39d .config console log report ci2-upstream-kcsan-gce
2020/07/01 10:46 upstream 7c30b859a947 090d8f7b .config console log report ci2-upstream-kcsan-gce
2020/07/01 07:58 upstream 7c30b859a947 c0383ebe .config console log report ci2-upstream-kcsan-gce
2020/07/01 02:49 upstream 7c30b859a947 c0383ebe .config console log report ci2-upstream-kcsan-gce
2020/07/01 01:08 upstream 7c30b859a947 c0383ebe .config console log report ci2-upstream-kcsan-gce
2020/06/30 22:15 upstream 7c30b859a947 c0383ebe .config console log report ci2-upstream-kcsan-gce
2020/06/30 20:45 upstream 7c30b859a947 c0383ebe .config console log report ci2-upstream-kcsan-gce
2020/06/30 19:15 upstream 7c30b859a947 917afeaa .config console log report ci2-upstream-kcsan-gce
2020/06/30 16:52 upstream 7c30b859a947 917afeaa .config console log report ci2-upstream-kcsan-gce
2020/06/30 13:09 upstream 7c30b859a947 917afeaa .config console log report ci2-upstream-kcsan-gce
2020/06/30 12:05 upstream 7c30b859a947 917afeaa .config console log report ci2-upstream-kcsan-gce
2020/06/30 08:15 upstream 7c30b859a947 917afeaa .config console log report ci2-upstream-kcsan-gce
2020/06/30 04:43 upstream 7c30b859a947 917afeaa .config console log report ci2-upstream-kcsan-gce
2020/06/30 03:16 upstream 7c30b859a947 917afeaa .config console log report ci2-upstream-kcsan-gce
2020/06/30 01:25 upstream 7c30b859a947 917afeaa .config console log report ci2-upstream-kcsan-gce
2020/06/29 18:25 upstream 7c30b859a947 ce9ef6f2 .config console log report ci2-upstream-kcsan-gce
2020/06/29 17:39 upstream 7c30b859a947 ce9ef6f2 .config console log report ci2-upstream-kcsan-gce
2020/06/29 10:35 upstream 9ebcfadb0610 3ff434cc .config console log report ci2-upstream-kcsan-gce
2020/06/29 08:42 upstream 9ebcfadb0610 0375051c .config console log report ci2-upstream-kcsan-gce
2020/06/29 06:10 upstream 9ebcfadb0610 0375051c .config console log report ci2-upstream-kcsan-gce
2020/06/29 04:15 upstream 9ebcfadb0610 a2cdad9d .config console log report ci2-upstream-kcsan-gce
2020/06/29 02:50 upstream 9ebcfadb0610 a2cdad9d .config console log report ci2-upstream-kcsan-gce
2020/06/29 00:30 upstream 91a9a90d040e a2cdad9d .config console log report ci2-upstream-kcsan-gce
2020/06/28 22:39 upstream 91a9a90d040e a2cdad9d .config console log report ci2-upstream-kcsan-gce
2020/06/28 21:38 upstream 91a9a90d040e a2cdad9d .config console log report ci2-upstream-kcsan-gce
2020/06/28 20:00 upstream 91a9a90d040e a2cdad9d .config console log report ci2-upstream-kcsan-gce
2020/06/28 13:02 upstream 719fdd32921f a2cdad9d .config console log report ci2-upstream-kcsan-gce
2020/06/28 11:10 upstream 719fdd32921f a2cdad9d .config console log report ci2-upstream-kcsan-gce
2020/06/28 07:49 upstream 916a3b0fc120 a2cdad9d .config console log report ci2-upstream-kcsan-gce
2020/06/28 01:24 upstream 916a3b0fc120 a2cdad9d .config console log report ci2-upstream-kcsan-gce
2020/06/27 19:15 upstream 6116dea80dfd a2cdad9d .config console log report ci2-upstream-kcsan-gce
2020/06/27 16:34 upstream 6116dea80dfd a2cdad9d .config console log report ci2-upstream-kcsan-gce
2020/06/27 15:29 upstream 1590a2e1c681 2defc703 .config console log report ci2-upstream-kcsan-gce
2020/06/27 14:23 upstream 1590a2e1c681 2defc703 .config console log report ci2-upstream-kcsan-gce
2020/06/27 12:51 upstream 1590a2e1c681 032b4239 .config console log report ci2-upstream-kcsan-gce
2020/06/27 11:39 upstream 1590a2e1c681 032b4239 .config console log report ci2-upstream-kcsan-gce
2020/06/27 09:03 upstream 1590a2e1c681 032b4239 .config console log report ci2-upstream-kcsan-gce
2020/06/27 04:13 upstream 1590a2e1c681 ffec44b5 .config console log report ci2-upstream-kcsan-gce
2020/06/27 02:23 upstream 1590a2e1c681 ffec44b5 .config console log report ci2-upstream-kcsan-gce
2020/06/27 00:11 upstream 1590a2e1c681 ffec44b5 .config console log report ci2-upstream-kcsan-gce
2020/06/26 22:16 upstream 1590a2e1c681 ffec44b5 .config console log report ci2-upstream-kcsan-gce
2020/06/26 20:20 upstream 1590a2e1c681 349959fb .config console log report ci2-upstream-kcsan-gce
2020/01/06 04:34 https://github.com/google/ktsan.git kcsan 245a43005292 438e1227 .config console log report ci2-upstream-kcsan-gce
2019/10/23 11:32 https://github.com/google/ktsan.git kcsan 05f2236801fe d0686497 .config console log report ci2-upstream-kcsan-gce
* Struck through repros no longer work on HEAD.