KCSAN: data-race in cgroup_procs_write_start / handle_mm

KCSAN: data-race in cgroup_procs_write_start / handle_mm_fault
Status: auto-closed as invalid on 2020/09/20 08:31
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 427d, last: 427d

similar bugs (4):
Kernel	Title	Count	Last	Reported	Patched	Status
upstream	KCSAN: data-race in cgroup_procs_write_start / handle_mm_fault (4)	1	210d	210d	0/22	auto-closed as invalid on 2021/04/25 00:05
upstream	KCSAN: data-race in cgroup_procs_write_start / handle_mm_fault (2)	2	322d	313d	0/22	auto-closed as invalid on 2021/01/03 02:26
upstream	KCSAN: data-race in cgroup_procs_write_start / handle_mm_fault (5)	1	175d	173d	0/22	auto-closed as invalid on 2021/05/30 07:22
upstream	KCSAN: data-race in cgroup_procs_write_start / handle_mm_fault (3)	1	257d	257d	0/22	auto-closed as invalid on 2021/03/09 10:11

Sample crash report:

==================================================================
BUG: KCSAN: data-race in cgroup_procs_write_start / handle_mm_fault

write to 0xffff8880a34214d8 of 1 bytes by task 10436 on cpu 0:
 mem_cgroup_enter_user_fault include/linux/memcontrol.h:650 [inline]
 handle_mm_fault+0x143/0x1af0 mm/memory.c:4449
 do_user_addr_fault+0x380/0x770 arch/x86/mm/fault.c:1294
 handle_page_fault arch/x86/mm/fault.c:1351 [inline]
 exc_page_fault+0xb8/0x330 arch/x86/mm/fault.c:1404
 asm_exc_page_fault+0x1e/0x30 arch/x86/include/asm/idtentry.h:538

read to 0xffff8880a34214d8 of 1 bytes by task 1 on cpu 1:
 cgroup_procs_write_start+0x13c/0x270 kernel/cgroup/cgroup.c:2796
 __cgroup1_procs_write+0x5d/0x220 kernel/cgroup/cgroup-v1.c:500
 cgroup1_procs_write+0x26/0x30 kernel/cgroup/cgroup-v1.c:532
 cgroup_file_write+0x15b/0x2d0 kernel/cgroup/cgroup.c:3697
 kernfs_fop_write+0x207/0x2c0 fs/kernfs/file.c:315
 vfs_write+0x1df/0x6f0 fs/read_write.c:576
 ksys_write+0xce/0x180 fs/read_write.c:631
 __do_sys_write fs/read_write.c:643 [inline]
 __se_sys_write fs/read_write.c:640 [inline]
 __x64_sys_write+0x3e/0x50 fs/read_write.c:640
 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: 1 Comm: systemd Not tainted 5.8.0-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	2020/08/16 08:31	upstream	4b6c093e21d3	5ce13532	.config	log	report