INFO: task kworker/u8:0:12 blocked for more than 123 seconds.
      Not tainted 6.12.38-syzkaller-gd0c633175c04 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:0    state:D stack:0     pid:12    tgid:12    ppid:2      flags:0x00004000
Workqueue: netns cleanup_net
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_timeout+0xb2/0x3a0 kernel/time/timer.c:2595
 do_wait_for_common kernel/sched/completion.c:95 [inline]
 __wait_for_common kernel/sched/completion.c:116 [inline]
 wait_for_common+0x359/0x630 kernel/sched/completion.c:127
 wait_for_completion+0x1c/0x40 kernel/sched/completion.c:148
 rcu_barrier+0x415/0x530 kernel/rcu/tree.c:4657
 netdev_run_todo+0x10e/0xcb0 net/core/dev.c:10868
 rtnl_unlock+0x12/0x20 net/core/rtnetlink.c:152
 cleanup_net+0x632/0xc70 net/core/net_namespace.c:638
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0x7d2/0x1020 kernel/workqueue.c:3319
 worker_thread+0xc58/0x1250 kernel/workqueue.c:3400
 kthread+0x2ca/0x370 kernel/kthread.c:389
 ret_from_fork+0x67/0xa0 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 37 Comm: khungtaskd Not tainted 6.12.38-syzkaller-gd0c633175c04 #0 79f03ae2e0a264f34f505a942aaa3597bcba712e
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+0x2ca/0x370 kernel/kthread.c:389
 ret_from_fork+0x67/0xa0 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: 20 Comm: rcuop/0 Not tainted 6.12.38-syzkaller-gd0c633175c04 #0 79f03ae2e0a264f34f505a942aaa3597bcba712e
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:stack_trace_consume_entry+0x4b/0x2a0 kernel/stacktrace.c:86
Code: 47 10 4c 89 c3 48 c1 eb 03 0f b6 04 13 84 c0 0f 85 14 01 00 00 44 8b 57 10 4c 8d 4f 08 4d 89 cd 49 c1 ed 03 41 0f b6 44 15 00 <84> c0 0f 85 2d 01 00 00 45 3b 11 73 3c 4c 8d 67 0c 4d 89 e7 49 c1
RSP: 0018:ffffc9000022ff50 EFLAGS: 00000a02
RAX: 0000000000000000 RBX: 1ffff9200004600e RCX: 000000000022ff00
RDX: dffffc0000000000 RSI: ffffffff847124a4 RDI: ffffc90000230060
RBP: ffffc9000022ff98 R08: ffffc90000230070 R09: ffffc90000230068
R10: 0000000000000010 R11: ffffffff81743c30 R12: ffff888103661300
R13: 1ffff9200004600d R14: ffffffff81743c30 R15: ffffc9000022ffa8
FS:  0000000000000000(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ff0695f84c0 CR3: 000000010a35a000 CR4: 00000000003526b0
Call Trace:
 <IRQ>
 arch_stack_walk+0x12d/0x170 arch/x86/kernel/stacktrace.c:27
 stack_trace_save+0x9d/0xe0 kernel/stacktrace.c:122
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:68
 kasan_save_free_info+0x4a/0x60 mm/kasan/generic.c:579
 poison_slab_object mm/kasan/common.c:247 [inline]
 __kasan_slab_free+0x5f/0x80 mm/kasan/common.c:264
 kasan_slab_free include/linux/kasan.h:233 [inline]
 slab_free_hook mm/slub.c:2417 [inline]
 slab_free mm/slub.c:4666 [inline]
 kmem_cache_free+0x1c1/0x510 mm/slub.c:4773
 kfree_skbmem net/core/skbuff.c:-1 [inline]
 __kfree_skb+0x18f/0x210 net/core/skbuff.c:1203
 sk_skb_reason_drop+0xd8/0x310 net/core/skbuff.c:1240
 kfree_skb_reason include/linux/skbuff.h:1271 [inline]
 kfree_skb include/linux/skbuff.h:1280 [inline]
 ip6_mc_input+0x4f3/0x670 net/ipv6/ip6_input.c:587
 dst_input include/net/dst.h:469 [inline]
 ip6_rcv_finish+0x341/0x3c0 net/ipv6/ip6_input.c:79
 NF_HOOK include/linux/netfilter.h:317 [inline]
 ipv6_rcv+0xed/0x220 net/ipv6/ip6_input.c:309
 __netif_receive_skb_one_core net/core/dev.c:5757 [inline]
 __netif_receive_skb net/core/dev.c:5870 [inline]
 netif_receive_skb_internal net/core/dev.c:5956 [inline]
 netif_receive_skb+0x147/0x7b0 net/core/dev.c:6015
 br_netif_receive_skb net/bridge/br_input.c:30 [inline]
 NF_HOOK include/linux/netfilter.h:317 [inline]
 br_pass_frame_up+0x126/0x1c0 net/bridge/br_input.c:70
 br_handle_frame_finish+0x12d9/0x1720 net/bridge/br_input.c:221
 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
 local_bh_enable include/linux/bottom_half.h:33 [inline]
 rcu_do_batch+0x5c6/0xd20 kernel/rcu/tree.c:2594
 nocb_cb_wait kernel/rcu/tree_nocb.h:923 [inline]
 rcu_nocb_cb_kthread+0x4dc/0xac0 kernel/rcu/tree_nocb.h:957
 kthread+0x2ca/0x370 kernel/kthread.c:389
 ret_from_fork+0x67/0xa0 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>