IPv6: ADDRCONF(NETDEV_CHANGE): batadv_slave_0: link becomes ready
==================================================================
BUG: KCSAN: data-race in pcpu_alloc / pcpu_balance_workfn

read-write to 0xffffffff870c89b4 of 4 bytes by task 2317 on cpu 0:
 pcpu_update_empty_pages mm/percpu.c:606 [inline]
 pcpu_chunk_populated mm/percpu.c:1534 [inline]
 pcpu_balance_populated mm/percpu.c:2095 [inline]
 pcpu_balance_workfn+0xb27/0xce0 mm/percpu.c:2246
 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 0xffffffff870c89b4 of 4 bytes by task 25 on cpu 1:
 pcpu_alloc+0x9c6/0x1040 mm/percpu.c:1877
 __alloc_percpu_gfp+0x22/0x30 mm/percpu.c:1937
 fib_nh_common_init+0x44/0x2c0 net/ipv4/fib_semantics.c:588
 fib6_nh_init+0xd9b/0x1370 net/ipv6/route.c:3608
 ip6_route_info_create+0x7ca/0xbb0 net/ipv6/route.c:3799
 ip6_route_add+0x22/0x100 net/ipv6/route.c:3843
 addrconf_prefix_route net/ipv6/addrconf.c:2425 [inline]
 addrconf_add_linklocal+0x293/0x380 net/ipv6/addrconf.c:3217
 addrconf_addr_gen+0x29f/0x470 net/ipv6/addrconf.c:3346
 addrconf_dev_config+0x196/0x250 net/ipv6/addrconf.c:3391
 addrconf_notify+0x7bf/0x950 net/ipv6/addrconf.c:3631
 notifier_call_chain kernel/notifier.c:87 [inline]
 raw_notifier_call_chain+0x53/0xb0 kernel/notifier.c:455
 call_netdevice_notifiers_info net/core/dev.c:1945 [inline]
 netdev_state_change+0xf4/0x170 net/core/dev.c:1334
 linkwatch_do_dev+0x228/0x260 net/core/link_watch.c:168
 __linkwatch_run_queue+0x2ad/0x540 net/core/link_watch.c:221
 linkwatch_event+0x3c/0x50 net/core/link_watch.c:264
 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: 0x00000001 -> 0x00000004

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 25 Comm: kworker/1:1 Not tainted 6.0.0-rc1-syzkaller-00368-gf31c32efd57c-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/22/2022
Workqueue: events linkwatch_event
==================================================================
IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_batadv: link becomes ready
IPv6: ADDRCONF(NETDEV_CHANGE): batadv_slave_1: link becomes ready
IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_batadv: link becomes ready