INFO: task kworker/1:35:2872 blocked for more than 143 seconds. Not tainted 5.6.0-rc7-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kworker/1:35 D27352 2872 2 0x80004000 Workqueue: ipv6_addrconf addrconf_verify_work Call Trace: context_switch kernel/sched/core.c:3380 [inline] __schedule+0x7c9/0xc50 kernel/sched/core.c:4080 __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:168 [inline] _raw_spin_unlock_irq+0x1f/0x80 kernel/locking/spinlock.c:199 schedule+0x188/0x220 kernel/sched/core.c:4154 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:4213 __mutex_lock_common+0x129f/0x2fc0 kernel/locking/mutex.c:1033 addrconf_verify_work+0xa/0x20 net/ipv6/addrconf.c:4526 __mutex_lock kernel/locking/mutex.c:1103 [inline] mutex_lock_nested+0x1a/0x20 kernel/locking/mutex.c:1118 addrconf_verify_work+0xa/0x20 net/ipv6/addrconf.c:4526 process_one_work+0x76e/0xfd0 kernel/workqueue.c:2266 atomic_try_cmpxchg include/asm-generic/atomic-instrumented.h:694 [inline] queued_spin_lock include/asm-generic/qspinlock.h:78 [inline] do_raw_spin_lock+0xfe/0x800 kernel/locking/spinlock_debug.c:113 worker_thread+0xa7f/0x1450 kernel/workqueue.c:2412 kthread+0x317/0x340 kernel/kthread.c:255 rcu_lock_release+0x20/0x20 kthread_blkcg+0xd0/0xd0 kernel/kthread.c:1234 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 Showing all locks held in the system: 1 lock held by khungtaskd/996: #0: ffffffff890d9ac8 (rcu_read_lock){....}, at: rcu_lock_acquire+0x0/0x30 lib/xarray.c:75 4 locks held by kworker/u4:7/1120: 3 locks held by kworker/1:35/2872: #0: ffff888215164528 ((wq_completion)ipv6_addrconf){+.+.}, at: spin_unlock_irq include/linux/spinlock.h:388 [inline] #0: ffff888215164528 ((wq_completion)ipv6_addrconf){+.+.}, at: process_one_work+0x6df/0xfd0 kernel/workqueue.c:2239 #1: ffffc900081ffd88 ((addr_chk_work).work){+.+.}, at: process_one_work+0x71e/0xfd0 kernel/workqueue.c:2241 #2: ffffffff89390be0 (rtnl_mutex){+.+.}, at: addrconf_verify_work+0xa/0x20 net/ipv6/addrconf.c:4526 3 locks held by kworker/0:74/3153: #0: ffff8880aa426d28 ((wq_completion)events){+.+.}, at: spin_unlock_irq include/linux/spinlock.h:388 [inline] #0: ffff8880aa426d28 ((wq_completion)events){+.+.}, at: process_one_work+0x6df/0xfd0 kernel/workqueue.c:2239 #1: ffffc9000887fd88 (deferred_process_work){+.+.}, at: process_one_work+0x71e/0xfd0 kernel/workqueue.c:2241 #2: ffffffff89390be0 (rtnl_mutex){+.+.}, at: switchdev_deferred_process_work+0xa/0x20 net/switchdev/switchdev.c:74 1 lock held by in:imklog/6635: #0: ffff8880937873a0 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x24e/0x2f0 fs/file.c:826 1 lock held by syz-executor.0/9265: #0: ffffffff89390be0 (rtnl_mutex){+.+.}, at: tun_detach drivers/net/tun.c:737 [inline] #0: ffffffff89390be0 (rtnl_mutex){+.+.}, at: tun_chr_close+0x3c/0x130 drivers/net/tun.c:3459 1 lock held by systemd-udevd/9329: #0: ffffffff89390be0 (rtnl_mutex){+.+.}, at: devlink_compat_running_version+0x538/0x5a0 net/core/devlink.c:8243 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 996 Comm: khungtaskd Not tainted 5.6.0-rc7-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1e9/0x30e lib/dump_stack.c:118 nmi_cpu_backtrace+0x9f/0x180 lib/nmi_backtrace.c:101 arch_trigger_cpumask_backtrace+0x10/0x10 arch/x86/kernel/apic/hw_nmi.c:38 nmi_trigger_cpumask_backtrace+0x16a/0x280 lib/nmi_backtrace.c:62 check_hung_uninterruptible_tasks kernel/hung_task.c:205 [inline] watchdog+0xd2a/0xd40 kernel/hung_task.c:289 kthread+0x317/0x340 kernel/kthread.c:255 hungtask_pm_notify+0x50/0x50 kernel/hung_task.c:265 kthread_blkcg+0xd0/0xd0 kernel/kthread.c:1234 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 247 Comm: kworker/u4:5 Not tainted 5.6.0-rc7-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: bat_events batadv_nc_worker RIP: 0010:mark_lock+0x183/0x1650 kernel/locking/lockdep.c:3683 Code: 48 89 df e8 7f 85 56 00 44 85 3b 74 2f 41 bd 01 00 00 00 65 48 8b 04 25 28 00 00 00 48 3b 84 24 c0 00 00 00 0f 85 68 10 00 00 <44> 89 e8 48 8d 65 d8 5b 41 5c 41 5d 41 5e 41 5f 5d c3 e8 46 41 ff RSP: 0018:ffffc90001ae7a70 EFLAGS: 00000046 RAX: 3e60fcec4c83ae00 RBX: ffffffff8ab0eee0 RCX: ffffffff815a6057 RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8aedd960 RBP: ffffc90001ae7b68 R08: dffffc0000000000 R09: fffffbfff15dbb2d R10: fffffbfff15dbb2d R11: 0000000000000000 R12: 1ffff110151fcd8f R13: 0000000000000001 R14: 0000000000000006 R15: 0000000000000040 FS: 0000000000000000(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f9d593c3010 CR3: 000000009a169000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __lock_acquire+0xc5a/0x1bc0 kernel/locking/lockdep.c:3954 spin_unlock_bh include/linux/spinlock.h:383 [inline] batadv_nc_purge_paths+0x36f/0x400 net/batman-adv/network-coding.c:470 mark_held_locks kernel/locking/lockdep.c:3359 [inline] __trace_hardirqs_on_caller kernel/locking/lockdep.c:3388 [inline] lockdep_hardirqs_on+0x4f4/0x840 kernel/locking/lockdep.c:3433 __local_bh_enable_ip+0x133/0x230 kernel/softirq.c:194 spin_unlock_bh include/linux/spinlock.h:383 [inline] batadv_nc_purge_paths+0x36f/0x400 net/batman-adv/network-coding.c:470 __local_bh_enable_ip+0x133/0x230 kernel/softirq.c:194 batadv_nc_to_purge_nc_path_coding+0x120/0x120 net/batman-adv/network-coding.c:300 spin_unlock_bh include/linux/spinlock.h:383 [inline] batadv_nc_purge_paths+0x36f/0x400 net/batman-adv/network-coding.c:470 batadv_nc_worker+0x332/0x5e0 net/batman-adv/network-coding.c:721 process_one_work+0x76e/0xfd0 kernel/workqueue.c:2266 atomic_try_cmpxchg include/asm-generic/atomic-instrumented.h:694 [inline] queued_spin_lock include/asm-generic/qspinlock.h:78 [inline] do_raw_spin_lock+0xfe/0x800 kernel/locking/spinlock_debug.c:113 worker_thread+0xa7f/0x1450 kernel/workqueue.c:2412 kthread+0x317/0x340 kernel/kthread.c:255 rcu_lock_release+0x20/0x20 kthread_blkcg+0xd0/0xd0 kernel/kthread.c:1234 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352