INFO: task syz-executor:6002 blocked for more than 122 seconds. Not tainted 6.12.23-syzkaller-gd9fd901baa98 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor state:D stack:0 pid:6002 tgid:6002 ppid:1 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:5924 [inline] __schedule+0x145b/0x1f10 kernel/sched/core.c:7750 __schedule_loop kernel/sched/core.c:7831 [inline] schedule+0xc6/0x240 kernel/sched/core.c:7846 schedule_preempt_disabled+0x14/0x30 kernel/sched/core.c:7903 __mutex_lock_common kernel/locking/mutex.c:692 [inline] __mutex_lock+0x836/0x1b60 kernel/locking/mutex.c:786 __mutex_lock_slowpath+0xe/0x20 kernel/locking/mutex.c:1117 mutex_lock+0x102/0x1c0 kernel/locking/mutex.c:270 rtnl_lock+0x19/0x20 net/core/rtnetlink.c:79 ppp_exit_net+0x116/0x340 drivers/net/ppp/ppp_generic.c:1157 ops_exit_list net/core/net_namespace.c:173 [inline] setup_net+0x66c/0x990 net/core/net_namespace.c:388 copy_net_ns+0x513/0xa30 net/core/net_namespace.c:510 create_new_namespaces+0x3b5/0x720 kernel/nsproxy.c:110 unshare_nsproxy_namespaces+0x126/0x180 kernel/nsproxy.c:228 ksys_unshare+0x4fe/0x880 kernel/fork.c:3351 __do_sys_unshare kernel/fork.c:3422 [inline] __se_sys_unshare kernel/fork.c:3420 [inline] __x64_sys_unshare+0x3c/0x50 kernel/fork.c:3420 x64_sys_call+0x2998/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:273 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0x58/0xf0 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x76/0x7e RIP: 0033:0x7f6341b90127 RSP: 002b:00007ffcbe1c23a8 EFLAGS: 00000206 ORIG_RAX: 0000000000000110 RAX: ffffffffffffffda RBX: 00007f6341db5f40 RCX: 00007f6341b90127 RDX: 0000000000000005 RSI: 00007ffcbe1c2270 RDI: 0000000040000000 RBP: 00007f6341db6738 R08: 00007f63428e7d60 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000008 R13: 0000000000000003 R14: 0000000000000009 R15: 0000000000000000 INFO: task syz-executor:6025 blocked for more than 125 seconds. Not tainted 6.12.23-syzkaller-gd9fd901baa98 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor state:D stack:0 pid:6025 tgid:6025 ppid:1 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:5924 [inline] __schedule+0x145b/0x1f10 kernel/sched/core.c:7750 __schedule_loop kernel/sched/core.c:7831 [inline] schedule+0xc6/0x240 kernel/sched/core.c:7846 schedule_preempt_disabled+0x14/0x30 kernel/sched/core.c:7903 __mutex_lock_common kernel/locking/mutex.c:692 [inline] __mutex_lock+0x836/0x1b60 kernel/locking/mutex.c:786 __mutex_lock_slowpath+0xe/0x20 kernel/locking/mutex.c:1117 mutex_lock+0x102/0x1c0 kernel/locking/mutex.c:270 rtnl_lock net/core/rtnetlink.c:79 [inline] rtnetlink_rcv_msg+0x75f/0xa00 net/core/rtnetlink.c:6675 netlink_rcv_skb+0x22b/0x4a0 net/netlink/af_netlink.c:2537 rtnetlink_rcv+0x20/0x30 net/core/rtnetlink.c:6696 netlink_unicast_kernel net/netlink/af_netlink.c:1316 [inline] netlink_unicast+0x8c6/0xa60 net/netlink/af_netlink.c:1342 netlink_sendmsg+0x7f0/0xaf0 net/netlink/af_netlink.c:1886 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg net/socket.c:745 [inline] __sys_sendto+0x66a/0x6f0 net/socket.c:2217 __do_sys_sendto net/socket.c:2229 [inline] __se_sys_sendto net/socket.c:2225 [inline] __x64_sys_sendto+0xe9/0x100 net/socket.c:2225 x64_sys_call+0x2c2c/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:45 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0x58/0xf0 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x76/0x7e RIP: 0033:0x7f2d91b90763 RSP: 002b:00007ffc3dbdbcf8 EFLAGS: 00000202 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 00007f2d928e4620 RCX: 00007f2d91b90763 RDX: 0000000000000028 RSI: 00007f2d928e4670 RDI: 0000000000000003 RBP: 0000000000000001 R08: 00007ffc3dbdbd14 R09: 000000000000000c R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000003 R13: 0000000000000000 R14: 00007f2d928e4670 R15: 0000000000000000 NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 37 Comm: khungtaskd Not tainted 6.12.23-syzkaller-gd9fd901baa98 #0 f1acc3ef52b3e732a05c4f7a2560722db90bb473 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Call Trace: __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:229 [inline] watchdog+0xd8f/0xed0 kernel/hung_task.c:385 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 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 305 Comm: kworker/u8:4 Not tainted 6.12.23-syzkaller-gd9fd901baa98 #0 f1acc3ef52b3e732a05c4f7a2560722db90bb473 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Workqueue: netns cleanup_net RIP: 0010:unwind_next_frame+0x30a/0x750 arch/x86/kernel/unwind_frame.c:305 Code: 10 00 74 08 48 89 df e8 e4 88 97 00 48 c7 03 00 00 00 00 b0 01 e9 a4 02 00 00 4c 8d 6b 50 4d 89 ee 49 c1 ee 03 41 80 3c 16 00 <74> 12 4c 89 ef e8 9c 87 97 00 48 ba 00 00 00 00 00 fc ff df 49 8b RSP: 0018:ffffc900000074e8 EFLAGS: 00000246 RAX: ffffc9000b72ff30 RBX: ffffc90000007568 RCX: 1ffff92000000e00 RDX: dffffc0000000000 RSI: ffffffff8173e57d RDI: ffffc9000b72ff48 RBP: ffffc90000007558 R08: ffffc90000007630 R09: ffffc90000007628 R10: 0000000000000000 R11: ffffffff8173e5d0 R12: 0000000000000000 R13: ffffc900000075b8 R14: 1ffff92000000eb7 R15: ffffc900000075f0 FS: 0000000000000000(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000564d4fe1eb98 CR3: 000000010bb9a000 CR4: 00000000003526b0 DR0: 0000000000000000 DR1: 0000000000000008 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: arch_stack_walk+0x139/0x170 arch/x86/kernel/stacktrace.c:25 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:2421 [inline] slab_free mm/slub.c:4665 [inline] kmem_cache_free+0x1c1/0x4c0 mm/slub.c:4770 kfree_skbmem net/core/skbuff.c:-1 [inline] __kfree_skb+0x18f/0x210 net/core/skbuff.c:1215 sk_skb_reason_drop+0xd8/0x310 net/core/skbuff.c:1252 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] process_backlog+0x44b/0xae0 net/core/dev.c:6202 __napi_poll+0xd0/0x610 net/core/dev.c:6853 napi_poll net/core/dev.c:6922 [inline] net_rx_action+0x584/0xce0 net/core/dev.c:7044 handle_softirqs+0x1ab/0x630 kernel/softirq.c:603 __do_softirq+0xf/0x16 kernel/softirq.c:641 do_softirq+0xa6/0x100 kernel/softirq.c:485 __local_bh_enable_ip+0x74/0x80 kernel/softirq.c:412 __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] addrconf_ifdown+0x608/0x1940 net/ipv6/addrconf.c:3953 addrconf_notify+0x17a/0xea0 net/ipv6/addrconf.c:-1 notifier_call_chain+0x10b/0x2c0 kernel/notifier.c:93 raw_notifier_call_chain+0x31/0x40 kernel/notifier.c:461 call_netdevice_notifiers_info net/core/dev.c:2067 [inline] call_netdevice_notifiers_extack net/core/dev.c:2105 [inline] call_netdevice_notifiers net/core/dev.c:2119 [inline] unregister_netdevice_many_notify+0xe32/0x1bd0 net/core/dev.c:11485 unregister_netdevice_many net/core/dev.c:11547 [inline] default_device_exit_batch+0x810/0x8a0 net/core/dev.c:12030 ops_exit_list net/core/net_namespace.c:178 [inline] cleanup_net+0x72e/0xc70 net/core/net_namespace.c:642 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+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