syzbot


KCSAN: data-race in __ptrace_unlink / ptrace_stop (2)

Status: auto-closed as invalid on 2020/12/22 11:57
Subsystems: kernel
[Documentation on labels]
Reported-by: syzbot+4a13fc71ee115c447358@syzkaller.appspotmail.com
First crash: 1256d, last: 1256d
Similar bugs (3)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in __ptrace_unlink / ptrace_stop kernel 1 1543d 1543d 0/26 auto-closed as invalid on 2020/04/14 15:22
upstream KCSAN: data-race in __ptrace_unlink / ptrace_stop (4) kernel 1 1063d 1063d 0/26 auto-closed as invalid on 2021/07/03 09:14
upstream KCSAN: data-race in __ptrace_unlink / ptrace_stop (3) kernel 1 1125d 1125d 0/26 auto-closed as invalid on 2021/05/17 11:16

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

read-write to 0xffff88810e06f064 of 4 bytes by task 23499 on cpu 1:
 freezer_count include/linux/freezer.h:121 [inline]
 freezable_schedule include/linux/freezer.h:173 [inline]
 ptrace_stop+0x36e/0x620 kernel/signal.c:2216
 ptrace_signal kernel/signal.c:2491 [inline]
 get_signal+0xbed/0x1510 kernel/signal.c:2654
 arch_do_signal+0x25/0x260 arch/x86/kernel/signal.c:811
 exit_to_user_mode_loop kernel/entry/common.c:161 [inline]
 exit_to_user_mode_prepare+0xde/0x170 kernel/entry/common.c:191
 syscall_exit_to_user_mode+0x16/0x30 kernel/entry/common.c:266
 do_syscall_64+0x45/0x80 arch/x86/entry/common.c:56
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff88810e06f064 of 4 bytes by task 23500 on cpu 0:
 __ptrace_unlink+0x185/0x2f0 kernel/ptrace.c:144
 __ptrace_detach+0x1b/0x1a0 kernel/ptrace.c:528
 exit_ptrace+0x93/0x160 kernel/ptrace.c:588
 forget_original_parent kernel/exit.c:613 [inline]
 exit_notify kernel/exit.c:653 [inline]
 do_exit+0x11b3/0x15a0 kernel/exit.c:829
 do_group_exit+0xc8/0x170 kernel/exit.c:906
 get_signal+0xf9b/0x1510 kernel/signal.c:2758
 arch_do_signal+0x25/0x260 arch/x86/kernel/signal.c:811
 exit_to_user_mode_loop kernel/entry/common.c:161 [inline]
 exit_to_user_mode_prepare+0xde/0x170 kernel/entry/common.c:191
 syscall_exit_to_user_mode+0x16/0x30 kernel/entry/common.c:266
 do_syscall_64+0x45/0x80 arch/x86/entry/common.c:56
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 23500 Comm: syz-executor.5 Not tainted 5.10.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2020/11/17 11:56 upstream 9c87c9f41245 bd2a760b .config console log report info ci2-upstream-kcsan-gce
* Struck through repros no longer work on HEAD.