INFO: task syz-executor.4:20565 can't die for more than 143 seconds. task:syz-executor.4 state:D stack:28496 pid:20565 ppid: 8449 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:4329 [inline] __schedule+0x917/0x2170 kernel/sched/core.c:5079 schedule+0xcf/0x270 kernel/sched/core.c:5158 schedule_timeout+0x1db/0x250 kernel/time/timer.c:1854 do_wait_for_common kernel/sched/completion.c:85 [inline] __wait_for_common kernel/sched/completion.c:106 [inline] wait_for_common kernel/sched/completion.c:117 [inline] wait_for_completion+0x168/0x270 kernel/sched/completion.c:138 flush_workqueue+0x3ff/0x13e0 kernel/workqueue.c:2838 nbd_start_device_ioctl drivers/block/nbd.c:1331 [inline] __nbd_ioctl drivers/block/nbd.c:1392 [inline] nbd_ioctl+0x60e/0xa50 drivers/block/nbd.c:1432 blkdev_ioctl+0x2a1/0x6d0 block/ioctl.c:583 block_ioctl+0xf9/0x140 fs/block_dev.c:1670 vfs_ioctl fs/ioctl.c:48 [inline] __do_sys_ioctl fs/ioctl.c:753 [inline] __se_sys_ioctl fs/ioctl.c:739 [inline] __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:739 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x466459 RSP: 002b:00007f55f4830188 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 000000000056c008 RCX: 0000000000466459 RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000003 RBP: 00000000004bf9fb R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056c008 R13: 00007ffec8ecb17f R14: 00007f55f4830300 R15: 0000000000022000 INFO: task syz-executor.4:20565 blocked for more than 143 seconds. Not tainted 5.12.0-rc6-next-20210409-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor.4 state:D stack:28496 pid:20565 ppid: 8449 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:4329 [inline] __schedule+0x917/0x2170 kernel/sched/core.c:5079 schedule+0xcf/0x270 kernel/sched/core.c:5158 schedule_timeout+0x1db/0x250 kernel/time/timer.c:1854 do_wait_for_common kernel/sched/completion.c:85 [inline] __wait_for_common kernel/sched/completion.c:106 [inline] wait_for_common kernel/sched/completion.c:117 [inline] wait_for_completion+0x168/0x270 kernel/sched/completion.c:138 flush_workqueue+0x3ff/0x13e0 kernel/workqueue.c:2838 nbd_start_device_ioctl drivers/block/nbd.c:1331 [inline] __nbd_ioctl drivers/block/nbd.c:1392 [inline] nbd_ioctl+0x60e/0xa50 drivers/block/nbd.c:1432 blkdev_ioctl+0x2a1/0x6d0 block/ioctl.c:583 block_ioctl+0xf9/0x140 fs/block_dev.c:1670 vfs_ioctl fs/ioctl.c:48 [inline] __do_sys_ioctl fs/ioctl.c:753 [inline] __se_sys_ioctl fs/ioctl.c:739 [inline] __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:739 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x466459 RSP: 002b:00007f55f4830188 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 000000000056c008 RCX: 0000000000466459 RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000003 RBP: 00000000004bf9fb R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056c008 R13: 00007ffec8ecb17f R14: 00007f55f4830300 R15: 0000000000022000 Showing all locks held in the system: 1 lock held by khungtaskd/1649: #0: ffffffff8bf752a0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:6333 1 lock held by systemd-journal/4841: 2 locks held by in:imklog/8128: #0: ffff8880124d8870 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:990 #1: ffff8880b9d35318 (&rq->lock){-.-.}-{2:2}, at: rq_lock kernel/sched/sched.h:1329 [inline] #1: ffff8880b9d35318 (&rq->lock){-.-.}-{2:2}, at: __schedule+0x222/0x2170 kernel/sched/core.c:4996 3 locks held by kworker/u5:1/8453: #0: ffff88801996f938 ((wq_completion)knbd4-recv){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff88801996f938 ((wq_completion)knbd4-recv){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:856 [inline] #0: ffff88801996f938 ((wq_completion)knbd4-recv){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:41 [inline] #0: ffff88801996f938 ((wq_completion)knbd4-recv){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:616 [inline] #0: ffff88801996f938 ((wq_completion)knbd4-recv){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline] #0: ffff88801996f938 ((wq_completion)knbd4-recv){+.+.}-{0:0}, at: process_one_work+0x871/0x1600 kernel/workqueue.c:2246 #1: ffffc9000176fda8 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_one_work+0x8a5/0x1600 kernel/workqueue.c:2250 #2: ffff888019fa7120 (sk_lock-AF_AX25){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1607 [inline] #2: ffff888019fa7120 (sk_lock-AF_AX25){+.+.}-{0:0}, at: ax25_recvmsg+0xbc/0x850 net/ax25/af_ax25.c:1627 4 locks held by kworker/0:7/9728: #0: ffff8880b9c35318 (&rq->lock){-.-.}-{2:2}, at: newidle_balance+0x7fe/0xe70 kernel/sched/fair.c:10643 #1: ffff8880b9c1f988 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x1b8/0x670 kernel/sched/psi.c:862 #2: ffff8880b9c24218 (&base->lock){-.-.}-{2:2}, at: lock_timer_base+0x5a/0x1f0 kernel/time/timer.c:944 #3: ffffffff8dc875c8 (&____s->seqcount#6){...-}-{0:0}, at: debug_object_activate+0x12e/0x3e0 lib/debugobjects.c:656 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1649 Comm: khungtaskd Not tainted 5.12.0-rc6-next-20210409-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:79 [inline] dump_stack+0x141/0x1d7 lib/dump_stack.c:120 nmi_cpu_backtrace.cold+0x44/0xd7 lib/nmi_backtrace.c:105 nmi_trigger_cpumask_backtrace+0x1b3/0x230 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:253 [inline] watchdog+0xd3b/0xf50 kernel/hung_task.c:338 kthread+0x3b1/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 9694 Comm: kworker/1:6 Not tainted 5.12.0-rc6-next-20210409-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: events nsim_dev_trap_report_work RIP: 0010:lockdep_recursion_finish kernel/locking/lockdep.c:438 [inline] RIP: 0010:lockdep_hardirqs_on_prepare kernel/locking/lockdep.c:4168 [inline] RIP: 0010:lockdep_hardirqs_on_prepare+0x16f/0x400 kernel/locking/lockdep.c:4119 Code: 00 00 fc ff df 48 89 fa 48 c1 ea 03 0f b6 04 02 84 c0 74 08 3c 03 0f 8e 8d 01 00 00 8b 85 d8 09 00 00 85 c0 0f 85 0f 01 00 00 <48> c7 c7 e0 9f 6b 89 e8 95 26 b6 07 b8 ff ff ff ff 65 0f c1 05 58 RSP: 0018:ffffc9000a647ac8 EFLAGS: 00000082 RAX: 0000000000000001 RBX: ffff888019e53900 RCX: 1ffffffff1f6a18a RDX: dffffc0000000000 RSI: 0000000000000040 RDI: ffffffff8fb50c50 RBP: ffff888019e53900 R08: 0000000000000000 R09: ffffffff8fafc97f R10: 0000000000000001 R11: 000000000000003f R12: 0000000000000000 R13: ffff888010842140 R14: 0000000000000000 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fcb4b148000 CR3: 00000000151ab000 CR4: 00000000001506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600 Call Trace: trace_hardirqs_on+0x5b/0x1c0 kernel/trace/trace_preemptirq.c:49 slab_free_hook mm/slub.c:1564 [inline] slab_free_freelist_hook+0x142/0x240 mm/slub.c:1618 slab_free mm/slub.c:3178 [inline] kfree+0xe5/0x7f0 mm/slub.c:4245 skb_free_head net/core/skbuff.c:651 [inline] skb_release_data+0x622/0x750 net/core/skbuff.c:672 skb_release_all net/core/skbuff.c:726 [inline] __kfree_skb net/core/skbuff.c:740 [inline] consume_skb net/core/skbuff.c:896 [inline] consume_skb+0xc2/0x160 net/core/skbuff.c:890 nsim_dev_trap_report drivers/net/netdevsim/dev.c:586 [inline] nsim_dev_trap_report_work+0x86f/0xbd0 drivers/net/netdevsim/dev.c:611 process_one_work+0x98d/0x1600 kernel/workqueue.c:2275 worker_thread+0x64c/0x1120 kernel/workqueue.c:2421 kthread+0x3b1/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294