syzbot

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BUG: KCSAN: data-race in prandom_seed / prandom_u32

write to 0xffff888237c28850 of 8 bytes by task 34 on cpu 0:
 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 0xffff888237c28850 of 8 bytes by task 1914 on cpu 1:
 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: 0x03399c5a4ec7427f -> 0xf8cccffa14535866

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 1914 Comm: kworker/1:7 Not tainted 5.18.0-rc7-syzkaller-00015-gef1302160bfb-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: ipv6_addrconf addrconf_dad_work
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