KCSAN: data-race in batadv_hardif_enable_interface / batadv_iv_ogm_schedule

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 58e1100fdc59 MAINTAINERS: co-maintain random.c
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=17c96145b00000
kernel config: https://syzkaller.appspot.com/x/.config?x=5308954916f6d362
dashboard link: https://syzkaller.appspot.com/bug?extid=219d17250fb1b31e6e5e
compiler: Debian clang version 11.0.1-2, GNU ld (GNU Binutils for Debian) 2.35.2
CC: [a...@unstable.cc b.a.t...@lists.open-mesh.org da...@davemloft.net ku...@kernel.org linux-...@vger.kernel.org marekl...@neomailbox.ch net...@vger.kernel.org sv...@narfation.org s...@simonwunderlich.de]

Unfortunately, I don't have any reproducer for this issue yet.

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+219d17...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in batadv_hardif_enable_interface / batadv_iv_ogm_schedule

write to 0xffff88816bec9c68 of 8 bytes by task 25885 on cpu 1:
batadv_hardif_enable_interface+0x10a/0x810 net/batman-adv/hard-interface.c:696
batadv_softif_slave_add+0x5e/0xd0 net/batman-adv/soft-interface.c:836
do_set_master net/core/rtnetlink.c:2521 [inline]
__rtnl_newlink net/core/rtnetlink.c:3475 [inline]
rtnl_newlink+0x1298/0x13b0 net/core/rtnetlink.c:3506
rtnetlink_rcv_msg+0x745/0x7e0 net/core/rtnetlink.c:5571
netlink_rcv_skb+0x14e/0x250 net/netlink/af_netlink.c:2491
rtnetlink_rcv+0x18/0x20 net/core/rtnetlink.c:5589
netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline]
netlink_unicast+0x5fc/0x6c0 net/netlink/af_netlink.c:1345
netlink_sendmsg+0x6e1/0x7d0 net/netlink/af_netlink.c:1916
sock_sendmsg_nosec net/socket.c:704 [inline]
sock_sendmsg net/socket.c:724 [inline]
____sys_sendmsg+0x39a/0x510 net/socket.c:2409
___sys_sendmsg net/socket.c:2463 [inline]
__sys_sendmsg+0x195/0x230 net/socket.c:2492
__do_sys_sendmsg net/socket.c:2501 [inline]
__se_sys_sendmsg net/socket.c:2499 [inline]
__x64_sys_sendmsg+0x42/0x50 net/socket.c:2499
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff88816bec9c68 of 8 bytes by task 17675 on cpu 0:
batadv_iv_ogm_schedule_buff net/batman-adv/bat_iv_ogm.c:844 [inline]
batadv_iv_ogm_schedule+0x549/0x7e0 net/batman-adv/bat_iv_ogm.c:869
batadv_iv_send_outstanding_bat_ogm_packet+0x474/0x4c0 net/batman-adv/bat_iv_ogm.c:1713
process_one_work+0x3fc/0x980 kernel/workqueue.c:2298
worker_thread+0x616/0xa70 kernel/workqueue.c:2445
kthread+0x2c7/0x2e0 kernel/kthread.c:327
ret_from_fork+0x1f/0x30

value changed: 0x0000000000000000 -> 0xffff88813896d000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 17675 Comm: kworker/u4:4 Not tainted 5.16.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: bat_events batadv_iv_send_outstanding_bat_ogm_packet

==================================================================


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.