syzbot


KCSAN: data-race in __ptrace_unlink / do_exit (6)

Status: auto-closed as invalid on 2021/12/06 01:33
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 496d, last: 397d
similar bugs (5):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in __ptrace_unlink / do_exit (3) 1 709d 709d 0/24 auto-closed as invalid on 2021/01/27 14:46
upstream KCSAN: data-race in __ptrace_unlink / do_exit 4 831d 883d 0/24 auto-closed as invalid on 2020/09/28 07:37
upstream KCSAN: data-race in __ptrace_unlink / do_exit (2) 4 757d 726d 0/24 auto-closed as invalid on 2020/12/21 11:46
upstream KCSAN: data-race in __ptrace_unlink / do_exit (5) 2 570d 581d 0/24 auto-closed as invalid on 2021/06/15 19:49
upstream KCSAN: data-race in __ptrace_unlink / do_exit (4) 1 650d 650d 0/24 auto-closed as invalid on 2021/03/28 11:03

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

write to 0xffff888126f82030 of 4 bytes by task 15782 on cpu 1:
 __ptrace_unlink+0x162/0x320 kernel/ptrace.c:133
 __ptrace_detach+0x1b/0x1d0 kernel/ptrace.c:539
 exit_ptrace+0x93/0x160 kernel/ptrace.c:599
 forget_original_parent kernel/exit.c:628 [inline]
 exit_notify kernel/exit.c:668 [inline]
 do_exit+0x11ce/0x14a0 kernel/exit.c:845
 do_group_exit+0xce/0x1a0 kernel/exit.c:922
 get_signal+0xf63/0x15a0 kernel/signal.c:2855
 arch_do_signal_or_restart+0x8c/0x280 arch/x86/kernel/signal.c:865
 handle_signal_work kernel/entry/common.c:148 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:172 [inline]
 exit_to_user_mode_prepare+0x109/0x190 kernel/entry/common.c:207
 __syscall_exit_to_user_mode_work kernel/entry/common.c:289 [inline]
 syscall_exit_to_user_mode+0x20/0x40 kernel/entry/common.c:300
 do_syscall_64+0x50/0xa0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff888126f82030 of 4 bytes by task 15676 on cpu 0:
 ptrace_event_enabled include/linux/ptrace.h:142 [inline]
 ptrace_event include/linux/ptrace.h:157 [inline]
 do_exit+0xff/0x14a0 kernel/exit.c:765
 do_group_exit+0xce/0x1a0 kernel/exit.c:922
 get_signal+0xf63/0x15a0 kernel/signal.c:2855
 arch_do_signal_or_restart+0x8c/0x280 arch/x86/kernel/signal.c:865
 handle_signal_work kernel/entry/common.c:148 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:172 [inline]
 exit_to_user_mode_prepare+0x109/0x190 kernel/entry/common.c:207
 __syscall_exit_to_user_mode_work kernel/entry/common.c:289 [inline]
 syscall_exit_to_user_mode+0x20/0x40 kernel/entry/common.c:300
 do_syscall_64+0x50/0xa0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x00010001 -> 0x00000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 15676 Comm: syz-executor.0 Not tainted 5.15.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (7):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci2-upstream-kcsan-gce 2021/11/01 01:24 upstream 8bb7eca972ad 098b5d53 .config log report info KCSAN: data-race in __ptrace_unlink / do_exit
ci2-upstream-kcsan-gce 2021/10/04 06:01 upstream 6761a0ae9895 db0f5787 .config log report info KCSAN: data-race in __ptrace_unlink / do_exit
ci2-upstream-kcsan-gce 2021/10/01 12:55 upstream 4de593fb965f 1d849ab4 .config log report info KCSAN: data-race in __ptrace_unlink / do_exit
ci2-upstream-kcsan-gce 2021/09/13 19:18 upstream 316346243be6 58d09404 .config log report info KCSAN: data-race in __ptrace_unlink / do_exit
ci2-upstream-kcsan-gce 2021/08/19 13:02 upstream d6d09a694205 a2fe1cb5 .config log report info KCSAN: data-race in __ptrace_unlink / do_exit
ci2-upstream-kcsan-gce 2021/08/13 18:41 upstream f8e6dfc64f61 2489ab88 .config log report info KCSAN: data-race in __ptrace_unlink / do_exit
ci2-upstream-kcsan-gce 2021/07/25 00:37 upstream 7ffca2bb9d8b 4d1b57d4 .config log report info KCSAN: data-race in __ptrace_unlink / do_exit
* Struck through repros no longer work on HEAD.