upstream test error: KCSAN: data-race in prandom_seed / prandom

upstream test error: KCSAN: data-race in prandom_seed / prandom_u32 (2)

Status: auto-closed as invalid on 2022/06/26 06:37
Subsystems: net
[Documentation on labels]
First crash: 982d, last: 982d

▶ ▼ Similar bugs (1)

Kernel	Title	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
upstream	upstream test error: KCSAN: data-race in prandom_seed / prandom_u32 net				1	1149d	1149d	0/28	auto-closed as invalid on 2022/01/10 22:18

Sample crash report:

==================================================================
BUG: KCSAN: data-race in prandom_seed / prandom_u32

write to 0xffff888237d28850 of 8 bytes by task 892 on cpu 1:
 siprand_u32 lib/random32.c:372 [inline]
 prandom_u32+0x11f/0x190 lib/random32.c:387
 mld_ifc_start_work net/ipv6/mcast.c:1071 [inline]
 mld_ifc_work+0x6dd/0x800 net/ipv6/mcast.c:2656
 process_one_work+0x3d3/0x720 kernel/workqueue.c:2289
 worker_thread+0x618/0xa70 kernel/workqueue.c:2436
 kthread+0x1a9/0x1e0 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30

read to 0xffff888237d28850 of 8 bytes by task 1826 on cpu 0:
 prandom_seed+0xd3/0x270 lib/random32.c:439
 addrconf_dad_begin net/ipv6/addrconf.c:3975 [inline]
 addrconf_dad_work+0x265/0xbb0 net/ipv6/addrconf.c:4100
 process_one_work+0x3d3/0x720 kernel/workqueue.c:2289
 worker_thread+0x618/0xa70 kernel/workqueue.c:2436
 kthread+0x1a9/0x1e0 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30

value changed: 0x44bd515016fc9e70 -> 0x30cc9d42add51a82

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 1826 Comm: kworker/0:3 Not tainted 5.18.0-rc7-syzkaller-00181-geaea45fc0e7b-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: ipv6_addrconf addrconf_dad_work
==================================================================

Crashes (1):
Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro	VM info	Assets (help?)	Manager	Title
2022/05/22 06:35	upstream	eaea45fc0e7b	7268fa62	.config	console log	report					ci2-upstream-kcsan-gce	upstream test error: KCSAN: data-race in prandom_seed / prandom_u32

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