INFO: task syz.5.3457:14424 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.5.3457 state:D stack:24112 pid:14424 ppid:13136 flags:0x00004006 Call Trace: context_switch kernel/sched/core.c:5246 [inline] __schedule+0x107f/0x4030 kernel/sched/core.c:6563 schedule+0xb9/0x180 kernel/sched/core.c:6639 perf_pending_task_sync kernel/events/core.c:5041 [inline] _free_event+0x176/0x1050 kernel/events/core.c:5047 put_event kernel/events/core.c:5172 [inline] perf_event_release_kernel+0x7c4/0x850 kernel/events/core.c:5297 perf_release+0x37/0x40 kernel/events/core.c:5307 __fput+0x20a/0x8b0 fs/file_table.c:320 task_work_run+0x1d0/0x260 kernel/task_work.c:203 exit_task_work include/linux/task_work.h:39 [inline] do_exit+0x9d5/0x2570 kernel/exit.c:887 do_group_exit+0x229/0x2e0 kernel/exit.c:1030 get_signal+0x1259/0x1340 kernel/signal.c:2884 arch_do_signal_or_restart+0xc4/0x1310 arch/x86/kernel/signal.c:871 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:177 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:213 __syscall_exit_to_user_mode_work kernel/entry/common.c:295 [inline] syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:306 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:82 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f08c9b9f559 RSP: 002b:00007f08ca9f5fd8 EFLAGS: 00000206 ORIG_RAX: 0000000000000038 RAX: fffffffffffffff4 RBX: 00007f08c9e25fa0 RCX: 00007f08c9b9f559 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000040100000 RBP: 00007f08c9c36b20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000 R13: 00007f08c9e26038 R14: 00007f08c9e25fa0 R15: 00007ffdb93f4b78 Showing all locks held in the system: 5 locks held by kworker/u4:1/11: 1 lock held by rcu_tasks_kthre/12: #0: ffffffff8d92e230 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xef0 kernel/rcu/tasks.h:517 1 lock held by rcu_tasks_trace/13: #0: ffffffff8d92ea50 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xef0 kernel/rcu/tasks.h:517 3 locks held by kworker/1:1/26: #0: ffff88802fc8a938 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267 #1: ffffc90000a1fd00 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267 #2: ffffffff8eb566e8 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_dad_work+0xc4/0x1500 net/ipv6/addrconf.c:4146 1 lock held by khungtaskd/28: #0: ffffffff8d92d8a0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #0: ffffffff8d92d8a0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline] #0: ffffffff8d92d8a0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6669 1 lock held by dhcpcd/3932: #0: ffffffff8eb566e8 (rtnl_mutex){+.+.}-{3:3}, at: netlink_dump+0xf0/0xcd0 net/netlink/af_netlink.c:2184 2 locks held by getty/4026: #0: ffff888031462098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:244 #1: ffffc9000327b2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x41e/0x1360 drivers/tty/n_tty.c:2198 3 locks held by kworker/u4:5/4303: 3 locks held by kworker/0:5/4380: #0: ffff88802fc8a938 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267 #1: ffffc90004537d00 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267 #2: ffffffff8eb566e8 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_dad_work+0xc4/0x1500 net/ipv6/addrconf.c:4146 2 locks held by kworker/0:6/4403: #0: ffff888018472138 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267 #1: ffffc90003d17d00 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267 3 locks held by kworker/u4:8/14735: #0: ffff88801dad5938 ((wq_completion)cfg80211){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267 #1: ffffc900035dfd00 ((work_completion)(&(&rdev->dfs_update_channels_wk)->work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267 #2: ffffffff8eb566e8 (rtnl_mutex){+.+.}-{3:3}, at: cfg80211_dfs_channels_update_work+0xc8/0x610 net/wireless/mlme.c:932 1 lock held by syz-executor/16016: #0: ffffffff8eb566e8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:74 [inline] #0: ffffffff8eb566e8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x80d/0xfb0 net/core/rtnetlink.c:6163 1 lock held by syz-executor/16072: #0: ffffffff8eb566e8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:74 [inline] #0: ffffffff8eb566e8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x80d/0xfb0 net/core/rtnetlink.c:6163 1 lock held by syz.7.3881/16244: #0: ffffffff8eb566e8 (rtnl_mutex){+.+.}-{3:3}, at: tun_detach drivers/net/tun.c:698 [inline] #0: ffffffff8eb566e8 (rtnl_mutex){+.+.}-{3:3}, at: tun_chr_close+0x3d/0x1b0 drivers/net/tun.c:3506 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 28 Comm: khungtaskd Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/07/2026 Call Trace: dump_stack_lvl+0x188/0x24e lib/dump_stack.c:106 nmi_cpu_backtrace+0x3e6/0x460 lib/nmi_backtrace.c:111 nmi_trigger_cpumask_backtrace+0x1d4/0x450 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:220 [inline] watchdog+0xf0e/0xf50 kernel/hung_task.c:377 kthread+0x29d/0x330 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 6219 Comm: kworker/u4:9 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/07/2026 Workqueue: events_unbound nsim_dev_trap_report_work RIP: 0010:on_stack arch/x86/include/asm/stacktrace.h:58 [inline] RIP: 0010:stack_access_ok arch/x86/kernel/unwind_orc.c:347 [inline] RIP: 0010:deref_stack_reg+0xa5/0x220 arch/x86/kernel/unwind_orc.c:357 Code: 77 10 4c 89 fb 48 c1 eb 03 0f b6 04 33 84 c0 0f 85 34 01 00 00 41 83 3f 00 0f 95 c0 4c 39 c5 0f 96 c1 20 c1 4d 39 c6 0f 97 c0 <20> c8 3c 01 75 18 49 8d 40 08 48 39 e8 0f 97 c1 4c 39 f0 0f 96 c0 RSP: 0018:ffffc9000d49f598 EFLAGS: 00000202 RAX: 0000000000000001 RBX: 1ffff92001a93ed1 RCX: 0000000000000001 RDX: ffffc9000d49f6c8 RSI: dffffc0000000000 RDI: ffffc9000d49f698 RBP: ffffc9000d498000 R08: ffffc9000d49fa30 R09: ffffc9000d49f6d8 R10: dffffc0000000000 R11: fffff52001a93edd R12: 1ffff92001a93ed2 R13: 1ffff92001a93ed3 R14: ffffc9000d4a0000 R15: ffffc9000d49f688 FS: 0000000000000000(0000) GS:ffff8880b8c00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f6f169f62f8 CR3: 00000000316e3000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: unwind_next_frame+0x15fc/0x1fd0 arch/x86/kernel/unwind_orc.c:-1 arch_stack_walk+0x10c/0x140 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0xa6/0xf0 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:46 [inline] kasan_set_track+0x4b/0x70 mm/kasan/common.c:53 kasan_save_free_info+0x27/0x40 mm/kasan/generic.c:516 ____kasan_slab_free+0x126/0x1f0 mm/kasan/common.c:237 kasan_slab_free include/linux/kasan.h:177 [inline] slab_free_hook mm/slub.c:1729 [inline] slab_free_freelist_hook+0x133/0x1b0 mm/slub.c:1755 slab_free mm/slub.c:3687 [inline] __kmem_cache_free+0xb6/0x200 mm/slub.c:3700 skb_free_head net/core/skbuff.c:762 [inline] skb_release_data+0x5e9/0x7e0 net/core/skbuff.c:791 skb_release_all net/core/skbuff.c:856 [inline] __kfree_skb net/core/skbuff.c:870 [inline] consume_skb+0xa2/0x100 net/core/skbuff.c:1038 nsim_dev_trap_report drivers/net/netdevsim/dev.c:821 [inline] nsim_dev_trap_report_work+0x71f/0xa80 drivers/net/netdevsim/dev.c:851 process_one_work+0x8ab/0x1160 kernel/workqueue.c:2292 worker_thread+0xaf5/0x12a0 kernel/workqueue.c:2439 kthread+0x29d/0x330 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295