[v5.15] BUG: soft lockup in batadv_dat_purge

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 1fe619a7d252 Linux 5.15.113
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=128a93b9280000
kernel config: https://syzkaller.appspot.com/x/.config?x=8f10ee30ae29b021
dashboard link: https://syzkaller.appspot.com/bug?extid=50365ba3affd9babaf65
compiler: Debian clang version 15.0.7, GNU ld (GNU Binutils for Debian) 2.35.2
userspace arch: arm64

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/1b707a1e1816/disk-1fe619a7.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/19cc598a8bbe/vmlinux-1fe619a7.xz
kernel image: https://storage.googleapis.com/syzbot-assets/a6cf7269bae5/Image-1fe619a7.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+50365b...@syzkaller.appspotmail.com

watchdog: BUG: soft lockup - CPU#0 stuck for 21s! [kworker/u4:2:148]
Modules linked in:
irq event stamp: 7053485
hardirqs last enabled at (7053483): [<ffff8000081b4dac>] __local_bh_enable_ip+0x258/0x4d0 kernel/softirq.c:388
hardirqs last disabled at (7053485): [<ffff80001194f688>] enter_el1_irq_or_nmi+0x10/0x1c arch/arm64/kernel/entry-common.c:227
softirqs last enabled at (7053482): [<ffff80001174ffe4>] spin_unlock_bh include/linux/spinlock.h:408 [inline]
softirqs last enabled at (7053482): [<ffff80001174ffe4>] __batadv_dat_purge+0x2d4/0x374 net/batman-adv/distributed-arp-table.c:187
softirqs last disabled at (7053484): [<ffff80001174fe08>] spin_lock_bh include/linux/spinlock.h:368 [inline]
softirqs last disabled at (7053484): [<ffff80001174fe08>] __batadv_dat_purge+0xf8/0x374 net/batman-adv/distributed-arp-table.c:175
CPU: 0 PID: 148 Comm: kworker/u4:2 Not tainted 5.15.113-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/28/2023
Workqueue: bat_events batadv_dat_purge
pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : lock_acquire+0x280/0x77c
lr : lockdep_recursion_finish kernel/locking/lockdep.c:436 [inline]
lr : lock_acquire+0x24c/0x77c kernel/locking/lockdep.c:5624
sp : ffff80001a3c7920
x29: ffff80001a3c7a10 x28: ffff700003478f2c x27: 0000000000000000
x26: ffff0001b47fbd00 x25: ffff0001257be1d8 x24: 0000000000000000
x23: 0000000100000201 x22: ffff0000c5429b40 x21: ffff800014830d00
x20: dfff800000000000 x19: ffff0001b47fbd00 x18: 0000000000000000
x17: ff8080000fd27aa0 x16: ffff80001195113c x15: ffff80000fd27aa0
x14: 1ffff0000291c06a x13: ffffffffffffffff x12: 0000000000000000
x11: ff8080000a9a3a24 x10: 0000000000000003 x9 : 0000000000000080
x8 : 00000000000000c0 x7 : ffff80001174fe08 x6 : 0000000000000000
x5 : 0000000000000000 x4 : 0000000000000001 x3 : 0000000000000000
x2 : 0000000000000008 x1 : ffff800011aabf00 x0 : 0000000000000000
Call trace:
arch_local_irq_restore arch/arm64/include/asm/irqflags.h:122 [inline]
lock_acquire+0x280/0x77c kernel/locking/lockdep.c:5625
__raw_spin_lock_bh include/linux/spinlock_api_smp.h:135 [inline]
_raw_spin_lock_bh+0x124/0x1c4 kernel/locking/spinlock.c:178
spin_lock_bh include/linux/spinlock.h:368 [inline]
__batadv_dat_purge+0xf8/0x374 net/batman-adv/distributed-arp-table.c:175
batadv_dat_purge+0x34/0x154 net/batman-adv/distributed-arp-table.c:206
process_one_work+0x790/0x11b8 kernel/workqueue.c:2307
worker_thread+0x910/0x1034 kernel/workqueue.c:2454
kthread+0x37c/0x45c kernel/kthread.c:319
ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:870


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

If the bug is already fixed, let syzbot know by replying with:
#syz fix: exact-commit-title

If you want to change bug's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)

If the bug is a duplicate of another bug, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup

[syzbot]

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