KCSAN: data-race in do_exit / ptrace

KCSAN: data-race in do_exit / ptrace_attach

Status: auto-closed as invalid on 2020/12/01 02:40
Subsystems: kernel
[Documentation on labels]
First crash: 1274d, last: 1274d

▶ ▼ Similar bugs (1)

Kernel	Title	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
upstream	KCSAN: data-race in do_exit / ptrace_attach (2) kernel				1	916d	916d	0/26	auto-closed as invalid on 2021/11/24 06:47

Sample crash report:

==================================================================
BUG: KCSAN: data-race in do_exit / ptrace_attach

write to 0xffff888024a55028 of 4 bytes by task 27184 on cpu 1:
 ptrace_attach+0x217/0x4b0 kernel/ptrace.c:413
 __do_sys_ptrace kernel/ptrace.c:1262 [inline]
 __se_sys_ptrace+0xc1/0x2e0 kernel/ptrace.c:1242
 __x64_sys_ptrace+0x51/0x60 kernel/ptrace.c:1242
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff888024a55028 of 4 bytes by task 27185 on cpu 0:
 ptrace_event_enabled include/linux/ptrace.h:142 [inline]
 ptrace_event include/linux/ptrace.h:157 [inline]
 do_exit+0xff/0x15a0 kernel/exit.c:747
 do_group_exit+0xc8/0x170 kernel/exit.c:903
 get_signal+0xf9b/0x1510 kernel/signal.c:2757
 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: 27185 Comm: syz-executor.5 Not tainted 5.10.0-rc1-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
2020/10/27 02:39	upstream	41ba50b0572e	8b3eaf58	.config	console log	report			info		ci2-upstream-kcsan-gce

* ~~Struck through~~ repros no longer work on HEAD.