KCSAN: data-race in do_coredump / do

KCSAN: data-race in do_coredump / do_nanosleep (2)

Status: auto-closed as invalid on 2021/01/13 08:56
Subsystems: kernel
[Documentation on labels]
First crash: 1230d, last: 1230d

▶ ▼ Similar bugs (1)

Kernel	Title	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
upstream	KCSAN: data-race in do_coredump / do_nanosleep kernel				1	1299d	1299d	0/26	auto-closed as invalid on 2020/11/05 08:43

Sample crash report:

==================================================================
BUG: KCSAN: data-race in do_coredump / do_nanosleep

read-write to 0xffff888105dc0024 of 4 bytes by task 8452 on cpu 0:
 freezer_count include/linux/freezer.h:121 [inline]
 freezable_schedule include/linux/freezer.h:173 [inline]
 do_nanosleep+0x111/0x390 kernel/time/hrtimer.c:1878
 hrtimer_nanosleep kernel/time/hrtimer.c:1931 [inline]
 __do_sys_nanosleep kernel/time/hrtimer.c:1965 [inline]
 __se_sys_nanosleep+0x20b/0x2a0 kernel/time/hrtimer.c:1952
 __x64_sys_nanosleep+0x2d/0x40 kernel/time/hrtimer.c:1952
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff888105dc0024 of 4 bytes by task 14668 on cpu 1:
 zap_threads fs/coredump.c:427 [inline]
 coredump_wait fs/coredump.c:462 [inline]
 do_coredump+0x3bd/0x1ea0 fs/coredump.c:629
 get_signal+0xf65/0x1510 kernel/signal.c:2752
 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: 1 PID: 14668 Comm: syz-executor.3 Not tainted 5.10.0-rc7-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
2020/12/09 08:52	upstream	a68a0262abda	99917735	.config	console log	report			info		ci2-upstream-kcsan-gce

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