KCSAN: data-race in ns_capable / task_dump

KCSAN: data-race in ns_capable / task_dump_owner (2)
Status: auto-closed as invalid on 2020/09/27 08:17
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 339d, last: 339d

similar bugs (3):
Kernel	Title	Count	Last	Reported	Patched	Status
upstream	KCSAN: data-race in ns_capable / task_dump_owner (4)	17	55d	103d	0/22	auto-closed as invalid on 2021/07/08 11:07
upstream	KCSAN: data-race in ns_capable / task_dump_owner (3)	1	187d	187d	0/22	auto-closed as invalid on 2021/02/26 13:47
upstream	KCSAN: data-race in ns_capable / task_dump_owner	1	392d	392d	0/22	auto-closed as invalid on 2020/08/04 20:26

Sample crash report:

==================================================================
BUG: KCSAN: data-race in ns_capable / task_dump_owner

write to 0xffff888094e61024 of 4 bytes by task 22600 on cpu 0:
 ns_capable_common kernel/capability.c:377 [inline]
 ns_capable+0x86/0xb0 kernel/capability.c:396
 __sys_setgid+0x8e/0x1a0 kernel/sys.c:435
 __do_sys_setgid kernel/sys.c:455 [inline]
 __se_sys_setgid kernel/sys.c:453 [inline]
 __x64_sys_setgid+0x1a/0x20 kernel/sys.c:453
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff888094e61024 of 4 bytes by task 5059 on cpu 1:
 task_dump_owner+0x2b/0x1b0 fs/proc/base.c:1818
 pid_update_inode fs/proc/base.c:1960 [inline]
 proc_pident_instantiate+0x138/0x190 fs/proc/base.c:2613
 proc_pident_lookup fs/proc/base.c:2637 [inline]
 proc_tgid_base_lookup+0x10c/0x180 fs/proc/base.c:3285
 lookup_open fs/namei.c:3082 [inline]
 open_last_lookups fs/namei.c:3177 [inline]
 path_openat+0xa6e/0x20a0 fs/namei.c:3365
 do_filp_open+0xbd/0x1d0 fs/namei.c:3395
 do_sys_openat2+0x33b/0x500 fs/open.c:1168
 do_sys_open fs/open.c:1184 [inline]
 __do_sys_open fs/open.c:1192 [inline]
 __se_sys_open fs/open.c:1188 [inline]
 __x64_sys_open+0xe2/0x110 fs/open.c:1188
 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: 5059 Comm: systemd-journal Not tainted 5.9.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (1):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro	VM info	Title
ci2-upstream-kcsan-gce	2020/08/23 08:17	upstream	c3d8f220d012	1da71ab0	.config	log	report