INFO: task syz.0.3271:19221 blocked for more than 143 seconds.
Tainted: G L syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.3271 state:D stack:25608 pid:19221 tgid:19220 ppid:5822 task_flags:0x400140 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5256 [inline]
__schedule+0x1139/0x6150 kernel/sched/core.c:6863
__schedule_loop kernel/sched/core.c:6945 [inline]
schedule+0xe7/0x3a0 kernel/sched/core.c:6960
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7017
__mutex_lock_common kernel/locking/mutex.c:692 [inline]
__mutex_lock+0xc69/0x1ca0 kernel/locking/mutex.c:776
sync_bdevs+0x153/0x480 block/bdev.c:1305
ksys_sync+0xb2/0x150 fs/sync.c:105
__do_sys_sync+0xe/0x20 fs/sync.c:113
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f4e64f8f749
RSP: 002b:00007f4e65ed1038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007f4e651e5fa0 RCX: 00007f4e64f8f749
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f4e651e5fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f4e651e6038 R14: 00007f4e651e5fa0 R15: 00007ffe72297b68
Showing all locks held in the system:
1 lock held by khungtaskd/31:
#0: ffffffff8e3c96a0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8e3c96a0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#0: ffffffff8e3c96a0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x36/0x1c0 kernel/locking/lockdep.c:6775
2 locks held by getty/5583:
#0: ffff888036e7b0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
#1: ffffc9000332b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x41b/0x1510 drivers/tty/n_tty.c:2211
3 locks held by kworker/1:12/5966:
1 lock held by udevd/6072:
#0: ffff8880262fd358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0x41a/0xe40 block/bdev.c:962
1 lock held by syz-executor/18518:
1 lock held by syz.6.3242/19109:
1 lock held by syz.0.3271/19221:
#0: ffff8880262fd358 (&disk->open_mutex){+.+.}-{4:4}, at: sync_bdevs+0x153/0x480 block/bdev.c:1305
=============================================
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
nmi_cpu_backtrace+0x27b/0x390 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x29c/0x300 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
__sys_info lib/sys_info.c:157 [inline]
sys_info+0x133/0x180 lib/sys_info.c:165
check_hung_uninterruptible_tasks kernel/hung_task.c:346 [inline]
watchdog+0xe66/0x1180 kernel/hung_task.c:515
kthread+0x3c5/0x780 kernel/kthread.c:463
ret_from_fork+0x983/0xb10 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 15304 Comm: kworker/u8:3 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: bat_events batadv_mcast_mla_update
RIP: 0010:__lock_is_held kernel/locking/lockdep.c:5599 [inline]
RIP: 0010:lock_is_held_type+0x9f/0x150 kernel/locking/lockdep.c:5940
Code: 08 41 8b 84 24 28 0b 00 00 85 c0 7f 17 e9 92 00 00 00 41 83 c7 01 45 3b bc 24 28 0b 00 00 0f 8d 80 00 00 00 49 63 c7 48 89 ee <48> 8d 04 80 49 8d 5c c5 00 48 89 df e8 90 fe ff ff 85 c0 74 d3 41
RSP: 0018:ffffc900031679d0 EFLAGS: 00000093
RAX: 0000000000000001 RBX: ffff888028b4d4b0 RCX: 0000000000000001
RDX: 0000000000000000 RSI: ffffffff90141ba8 RDI: ffff888028b4d4b0
RBP: ffffffff90141ba8 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000001 R11: ffff888028b4d4b0 R12: ffff888028b4c980
R13: ffff888028b4d4b0 R14: 00000000ffffffff R15: 0000000000000001
FS: 0000000000000000(0000) GS:ffff8881248f5000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000556bea560ad8 CR3: 000000000e184000 CR4: 00000000003526f0
Call Trace:
lock_is_held include/linux/lockdep.h:249 [inline]
lockdep_rtnl_is_held+0x1b/0x40 net/core/rtnetlink.c:182
__in6_dev_get include/net/addrconf.h:347 [inline]
batadv_mcast_mla_rtr_flags_meshif_get_ipv6 net/batman-adv/multicast.c:134 [inline]
batadv_mcast_mla_rtr_flags_meshif_get net/batman-adv/multicast.c:173 [inline]
batadv_mcast_mla_rtr_flags_get net/batman-adv/multicast.c:231 [inline]
batadv_mcast_mla_flags_get net/batman-adv/multicast.c:285 [inline]
__batadv_mcast_mla_update net/batman-adv/multicast.c:907 [inline]
batadv_mcast_mla_update+0x20c4/0x31b0 net/batman-adv/multicast.c:946
process_one_work+0x9ba/0x1b20 kernel/workqueue.c:3257
process_scheduled_works kernel/workqueue.c:3340 [inline]
worker_thread+0x6c8/0xf10 kernel/workqueue.c:3421
kthread+0x3c5/0x780 kernel/kthread.c:463
ret_from_fork+0x983/0xb10 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246