INFO: task syz.6.454:1860 blocked for more than 122 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.6.454       state:D stack:0     pid:1860  tgid:1860  ppid:614    flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5945 [inline]
 __schedule+0x1322/0x1df0 kernel/sched/core.c:7791
 __schedule_loop kernel/sched/core.c:7872 [inline]
 schedule+0xc6/0x240 kernel/sched/core.c:7887
 schedule_preempt_disabled+0x14/0x30 kernel/sched/core.c:7944
 __mutex_lock_common kernel/locking/mutex.c:707 [inline]
 __mutex_lock+0x81e/0x1b50 kernel/locking/mutex.c:803
 __mutex_lock_slowpath+0xe/0x20 kernel/locking/mutex.c:1134
 mutex_lock+0x102/0x1c0 kernel/locking/mutex.c:285
 rtnl_lock+0x19/0x20 net/core/rtnetlink.c:79
 tun_detach drivers/net/tun.c:698 [inline]
 tun_chr_close+0x41/0x150 drivers/net/tun.c:3517
 __fput+0x1fe/0xa00 fs/file_table.c:429
 ____fput+0x20/0x30 fs/file_table.c:457
 task_work_run+0x1e3/0x250 kernel/task_work.c:240
 exit_task_work include/linux/task_work.h:43 [inline]
 do_exit+0x9bc/0x2630 kernel/exit.c:953
 do_group_exit+0x22a/0x300 kernel/exit.c:1095
 get_signal+0x139d/0x14f0 kernel/signal.c:2933
 arch_do_signal_or_restart+0x96/0x720 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0x58/0xb0 kernel/entry/common.c:218
 do_syscall_64+0x64/0xf0 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7f7cf21c14a5
RSP: 002b:00007f7cf2f81f80 EFLAGS: 00000293 ORIG_RAX: 00000000000000e6
RAX: fffffffffffffdfc RBX: 00007f7cf23c5fa0 RCX: 00007f7cf21c14a5
RDX: 00007f7cf2f81fc0 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f7cf2211e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000000
R13: 00007f7cf23c6038 R14: 00007f7cf23c5fa0 R15: 00007ffec2d25eb8
 </TASK>
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 37 Comm: khungtaskd Not tainted syzkaller #0 3aa8e93a75ec4fb080c21ea51d8727149e6cfac5
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Call Trace:
 <TASK>
 __dump_stack+0x21/0x30 lib/dump_stack.c:94
 dump_stack_lvl+0x10c/0x190 lib/dump_stack.c:120
 dump_stack+0x19/0x20 lib/dump_stack.c:129
 nmi_cpu_backtrace+0x2bf/0x2d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x142/0x2c0 lib/nmi_backtrace.c:62
 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:41
 trigger_all_cpu_backtrace include/linux/nmi.h:158 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:267 [inline]
 watchdog+0xd8f/0xed0 kernel/hung_task.c:423
 kthread+0x2c7/0x370 kernel/kthread.c:389
 ret_from_fork+0x64/0xa0 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 3326 Comm: kworker/1:6 Not tainted syzkaller #0 3aa8e93a75ec4fb080c21ea51d8727149e6cfac5
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Workqueue: mld mld_query_work
RIP: 0010:__alloc_skb+0x7e/0x370 net/core/skbuff.c:667
Code: 48 89 5d b0 48 8d 1c dd 60 01 00 00 48 c7 c0 a0 da 20 87 48 c7 c7 a8 da 20 87 48 0f 44 f8 48 89 f8 48 c1 e8 03 42 80 3c 28 00 <74> 05 e8 db b0 74 fd 48 8b 9b 40 d9 20 87 e9 23 02 00 00 e8 0a 7c
RSP: 0018:ffffc900002305e0 EFLAGS: 00000246
RAX: 1ffffffff0e41b54 RBX: 0000000000000160 RCX: 0000000000000100
RDX: ffff888119231300 RSI: 0000000000000000 RDI: ffffffff8720daa0
RBP: ffffc90000230630 R08: 0000000000000000 R09: 1ffff920000460dc
R10: dffffc0000000000 R11: fffff520000460dd R12: 0000000000000820
R13: dffffc0000000000 R14: 00000000ffffffff R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f366f9f84c0 CR3: 00000000072a8000 CR4: 00000000003526b0
Call Trace:
 <IRQ>
 alloc_skb include/linux/skbuff.h:1331 [inline]
 nlmsg_new include/net/netlink.h:1015 [inline]
 fdb_notify+0x78/0x150 net/bridge/br_fdb.c:195
 br_fdb_update+0x4b7/0x680 net/bridge/br_fdb.c:941
 br_handle_frame_finish+0x39c/0x1720 net/bridge/br_input.c:141
 nf_hook_bridge_pre net/bridge/br_input.c:301 [inline]
 br_handle_frame+0x5a6/0xba0 net/bridge/br_input.c:424
 __netif_receive_skb_core+0xf4b/0x3940 net/core/dev.c:5651
 __netif_receive_skb_one_core net/core/dev.c:5755 [inline]
 __netif_receive_skb net/core/dev.c:5870 [inline]
 process_backlog+0x3e5/0xae0 net/core/dev.c:6206
 __napi_poll+0xd3/0x610 net/core/dev.c:6857
 napi_poll net/core/dev.c:6926 [inline]
 net_rx_action+0x584/0xce0 net/core/dev.c:7048
 handle_softirqs+0x1ab/0x630 kernel/softirq.c:621
 __do_softirq+0xf/0x16 kernel/softirq.c:659
 do_softirq+0xa6/0x100 kernel/softirq.c:503
 </IRQ>
 <TASK>
 __local_bh_enable_ip+0x74/0x80 kernel/softirq.c:430
 __raw_spin_unlock_bh include/linux/spinlock_api_smp.h:167 [inline]
 _raw_spin_unlock_bh+0x54/0x60 kernel/locking/spinlock.c:210
 spin_unlock_bh include/linux/spinlock.h:396 [inline]
 mld_query_work+0x951/0x2c10 net/ipv6/mcast.c:1529
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0x7d5/0x1020 kernel/workqueue.c:3319
 worker_thread+0xc58/0x1250 kernel/workqueue.c:3400
 kthread+0x2c7/0x370 kernel/kthread.c:389
 ret_from_fork+0x64/0xa0 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
net_ratelimit: 22841 callbacks suppressed
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)