KCSAN: data-race in do_group_exit / mm

KCSAN: data-race in do_group_exit / mm_release (3)

Status: auto-closed as invalid on 2020/12/21 16:29
Subsystems: kernel
[Documentation on labels]
Reported-by: syzbot+f06c9a522cdb9dcf9b77@syzkaller.appspotmail.com
First crash: 1854d, last: 1854d

▶ ▼ Similar bugs (2)

Kernel	Title	Rank 🛈	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
upstream	KCSAN: data-race in do_group_exit / mm_release (2) kernel	6				1	1892d	1892d	0/29	auto-closed as invalid on 2020/11/13 23:31
upstream	KCSAN: data-race in do_group_exit / mm_release kernel	6				1	1968d	1968d	0/29	auto-closed as invalid on 2020/08/30 02:37

Sample crash report:

==================================================================
BUG: KCSAN: data-race in do_group_exit / mm_release

write to 0xffff8881026771b4 of 4 bytes by task 27288 on cpu 0:
 do_group_exit+0x130/0x170 kernel/exit.c:900
 __do_sys_exit_group+0xb/0x10 kernel/exit.c:917
 __se_sys_exit_group+0x5/0x10 kernel/exit.c:915
 __x64_sys_exit_group+0x16/0x20 kernel/exit.c:915
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff8881026771b4 of 4 bytes by task 27305 on cpu 1:
 mm_release+0x92/0x1c0 kernel/fork.c:1299
 exit_mm_release+0x21/0x30 kernel/fork.c:1323
 exit_mm+0x4b/0x370 kernel/exit.c:438
 do_exit+0x3c2/0x15a0 kernel/exit.c:796
 __do_sys_exit+0xb/0x10 kernel/exit.c:875
 __se_sys_exit+0x5/0x10 kernel/exit.c:873
 __x64_sys_exit+0x16/0x20 kernel/exit.c:873
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 27305 Comm: syz-executor.2 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
2020/11/16 16:28	upstream	09162bc32c88	1bf9a662	.config	console log	report			info		ci2-upstream-kcsan-gce

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