INFO: task syz-executor.5:22213 blocked for more than 140 seconds. Not tainted 4.19.172-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.5 D27552 22213 8116 0x80000002 Call Trace: context_switch syzkaller/managers/linux-4-19/kernel/kernel/sched/core.c:2828 [inline] __schedule+0x887/0x2040 syzkaller/managers/linux-4-19/kernel/kernel/sched/core.c:3517 schedule+0x8d/0x1b0 syzkaller/managers/linux-4-19/kernel/kernel/sched/core.c:3561 schedule_preempt_disabled+0xf/0x20 syzkaller/managers/linux-4-19/kernel/kernel/sched/core.c:3619 __mutex_lock_common syzkaller/managers/linux-4-19/kernel/kernel/locking/mutex.c:1002 [inline] __mutex_lock+0x647/0x1260 syzkaller/managers/linux-4-19/kernel/kernel/locking/mutex.c:1072 unregister_netdev+0xe/0x20 syzkaller/managers/linux-4-19/kernel/net/core/dev.c:9337 slip_close+0x161/0x1c0 syzkaller/managers/linux-4-19/kernel/drivers/net/slip/slip.c:908 tty_ldisc_close+0xa2/0xd0 syzkaller/managers/linux-4-19/kernel/drivers/tty/tty_ldisc.c:493 tty_ldisc_kill syzkaller/managers/linux-4-19/kernel/drivers/tty/tty_ldisc.c:639 [inline] tty_ldisc_release+0xf5/0x440 syzkaller/managers/linux-4-19/kernel/drivers/tty/tty_ldisc.c:806 tty_release_struct+0x20/0xe0 syzkaller/managers/linux-4-19/kernel/drivers/tty/tty_io.c:1611 tty_release+0xc70/0x1210 syzkaller/managers/linux-4-19/kernel/drivers/tty/tty_io.c:1784 __fput+0x2ce/0x890 syzkaller/managers/linux-4-19/kernel/fs/file_table.c:278 task_work_run+0x148/0x1c0 syzkaller/managers/linux-4-19/kernel/kernel/task_work.c:113 exit_task_work syzkaller/managers/linux-4-19/kernel/./include/linux/task_work.h:22 [inline] do_exit+0xbf3/0x2be0 syzkaller/managers/linux-4-19/kernel/kernel/exit.c:870 do_group_exit+0x125/0x310 syzkaller/managers/linux-4-19/kernel/kernel/exit.c:967 get_signal+0x3f2/0x1f70 syzkaller/managers/linux-4-19/kernel/kernel/signal.c:2589 do_signal+0x8f/0x1670 syzkaller/managers/linux-4-19/kernel/arch/x86/kernel/signal.c:821 exit_to_usermode_loop+0x204/0x2a0 syzkaller/managers/linux-4-19/kernel/arch/x86/entry/common.c:163 prepare_exit_to_usermode syzkaller/managers/linux-4-19/kernel/arch/x86/entry/common.c:198 [inline] syscall_return_slowpath syzkaller/managers/linux-4-19/kernel/arch/x86/entry/common.c:271 [inline] do_syscall_64+0x538/0x620 syzkaller/managers/linux-4-19/kernel/arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x465b09 Code: Bad RIP value. RSP: 002b:00007fafe09b5218 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 000000000056bf68 RCX: 0000000000465b09 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 000000000056bf68 RBP: 000000000056bf60 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf6c R13: 00007ffe5afc6edf R14: 00007fafe09b5300 R15: 0000000000022000 INFO: task syz-executor.5:22256 blocked for more than 140 seconds. Not tainted 4.19.172-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.5 D27448 22256 8116 0x80000002 Call Trace: context_switch syzkaller/managers/linux-4-19/kernel/kernel/sched/core.c:2828 [inline] __schedule+0x887/0x2040 syzkaller/managers/linux-4-19/kernel/kernel/sched/core.c:3517 schedule+0x8d/0x1b0 syzkaller/managers/linux-4-19/kernel/kernel/sched/core.c:3561 schedule_timeout+0x92d/0xfe0 syzkaller/managers/linux-4-19/kernel/kernel/time/timer.c:1794 do_wait_for_common syzkaller/managers/linux-4-19/kernel/kernel/sched/completion.c:83 [inline] __wait_for_common syzkaller/managers/linux-4-19/kernel/kernel/sched/completion.c:104 [inline] wait_for_common+0x29c/0x470 syzkaller/managers/linux-4-19/kernel/kernel/sched/completion.c:115 __flush_work+0x4bb/0x8b0 syzkaller/managers/linux-4-19/kernel/kernel/workqueue.c:2928 flush_all_backlogs syzkaller/managers/linux-4-19/kernel/net/core/dev.c:5283 [inline] rollback_registered_many+0x4b1/0xe70 syzkaller/managers/linux-4-19/kernel/net/core/dev.c:8173 rollback_registered+0xe9/0x1b0 syzkaller/managers/linux-4-19/kernel/net/core/dev.c:8230 unregister_netdevice_queue+0x1de/0x3e0 syzkaller/managers/linux-4-19/kernel/net/core/dev.c:9297 unregister_netdevice syzkaller/managers/linux-4-19/kernel/./include/linux/netdevice.h:2614 [inline] unregister_netdev+0x18/0x20 syzkaller/managers/linux-4-19/kernel/net/core/dev.c:9338 slip_close+0x161/0x1c0 syzkaller/managers/linux-4-19/kernel/drivers/net/slip/slip.c:908 tty_ldisc_close+0xa2/0xd0 syzkaller/managers/linux-4-19/kernel/drivers/tty/tty_ldisc.c:493 tty_ldisc_kill syzkaller/managers/linux-4-19/kernel/drivers/tty/tty_ldisc.c:639 [inline] tty_ldisc_release+0xf5/0x440 syzkaller/managers/linux-4-19/kernel/drivers/tty/tty_ldisc.c:806 tty_release_struct+0x20/0xe0 syzkaller/managers/linux-4-19/kernel/drivers/tty/tty_io.c:1611 tty_release+0xc70/0x1210 syzkaller/managers/linux-4-19/kernel/drivers/tty/tty_io.c:1784 __fput+0x2ce/0x890 syzkaller/managers/linux-4-19/kernel/fs/file_table.c:278 task_work_run+0x148/0x1c0 syzkaller/managers/linux-4-19/kernel/kernel/task_work.c:113 exit_task_work syzkaller/managers/linux-4-19/kernel/./include/linux/task_work.h:22 [inline] do_exit+0xbf3/0x2be0 syzkaller/managers/linux-4-19/kernel/kernel/exit.c:870 do_group_exit+0x125/0x310 syzkaller/managers/linux-4-19/kernel/kernel/exit.c:967 get_signal+0x3f2/0x1f70 syzkaller/managers/linux-4-19/kernel/kernel/signal.c:2589 do_signal+0x8f/0x1670 syzkaller/managers/linux-4-19/kernel/arch/x86/kernel/signal.c:821 exit_to_usermode_loop+0x204/0x2a0 syzkaller/managers/linux-4-19/kernel/arch/x86/entry/common.c:163 prepare_exit_to_usermode syzkaller/managers/linux-4-19/kernel/arch/x86/entry/common.c:198 [inline] syscall_return_slowpath syzkaller/managers/linux-4-19/kernel/arch/x86/entry/common.c:271 [inline] do_syscall_64+0x538/0x620 syzkaller/managers/linux-4-19/kernel/arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x465b09 Code: Bad RIP value. RSP: 002b:00007fafe09b5218 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 000000000056bf68 RCX: 0000000000465b09 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 000000000056bf68 RBP: 000000000056bf60 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf6c R13: 00007ffe5afc6edf R14: 00007fafe09b5300 R15: 0000000000022000 Showing all locks held in the system: 1 lock held by khungtaskd/1567: #0: 000000001b9c518a (rcu_read_lock){....}, at: debug_show_all_locks+0x53/0x265 syzkaller/managers/linux-4-19/kernel/kernel/locking/lockdep.c:4440 1 lock held by in:imklog/7794: #0: 000000001282abd6 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x26f/0x310 syzkaller/managers/linux-4-19/kernel/fs/file.c:767 3 locks held by syz-executor.5/22213: #0: 0000000019d86815 (&tty->ldisc_sem){++++}, at: __tty_ldisc_lock syzkaller/managers/linux-4-19/kernel/drivers/tty/tty_ldisc.c:320 [inline] #0: 0000000019d86815 (&tty->ldisc_sem){++++}, at: tty_ldisc_lock_pair_timeout syzkaller/managers/linux-4-19/kernel/drivers/tty/tty_ldisc.c:376 [inline] #0: 0000000019d86815 (&tty->ldisc_sem){++++}, at: tty_ldisc_lock_pair syzkaller/managers/linux-4-19/kernel/drivers/tty/tty_ldisc.c:397 [inline] #0: 0000000019d86815 (&tty->ldisc_sem){++++}, at: tty_ldisc_release+0x240/0x440 syzkaller/managers/linux-4-19/kernel/drivers/tty/tty_ldisc.c:805 #1: 000000003684638c (&tty->ldisc_sem/1){+.+.}, at: __tty_ldisc_lock_nested syzkaller/managers/linux-4-19/kernel/drivers/tty/tty_ldisc.c:326 [inline] #1: 000000003684638c (&tty->ldisc_sem/1){+.+.}, at: tty_ldisc_lock_pair_timeout syzkaller/managers/linux-4-19/kernel/drivers/tty/tty_ldisc.c:378 [inline] #1: 000000003684638c (&tty->ldisc_sem/1){+.+.}, at: tty_ldisc_lock_pair syzkaller/managers/linux-4-19/kernel/drivers/tty/tty_ldisc.c:397 [inline] #1: 000000003684638c (&tty->ldisc_sem/1){+.+.}, at: tty_ldisc_release+0x354/0x440 syzkaller/managers/linux-4-19/kernel/drivers/tty/tty_ldisc.c:805 #2: 00000000eb219894 (rtnl_mutex){+.+.}, at: unregister_netdev+0xe/0x20 syzkaller/managers/linux-4-19/kernel/net/core/dev.c:9337 4 locks held by syz-executor.5/22256: #0: 00000000e45365ab (&tty->ldisc_sem){++++}, at: __tty_ldisc_lock syzkaller/managers/linux-4-19/kernel/drivers/tty/tty_ldisc.c:320 [inline] #0: 00000000e45365ab (&tty->ldisc_sem){++++}, at: tty_ldisc_lock_pair_timeout syzkaller/managers/linux-4-19/kernel/drivers/tty/tty_ldisc.c:376 [inline] #0: 00000000e45365ab (&tty->ldisc_sem){++++}, at: tty_ldisc_lock_pair syzkaller/managers/linux-4-19/kernel/drivers/tty/tty_ldisc.c:397 [inline] #0: 00000000e45365ab (&tty->ldisc_sem){++++}, at: tty_ldisc_release+0x240/0x440 syzkaller/managers/linux-4-19/kernel/drivers/tty/tty_ldisc.c:805 #1: 0000000076112790 (&tty->ldisc_sem/1){+.+.}, at: __tty_ldisc_lock_nested syzkaller/managers/linux-4-19/kernel/drivers/tty/tty_ldisc.c:326 [inline] #1: 0000000076112790 (&tty->ldisc_sem/1){+.+.}, at: tty_ldisc_lock_pair_timeout syzkaller/managers/linux-4-19/kernel/drivers/tty/tty_ldisc.c:378 [inline] #1: 0000000076112790 (&tty->ldisc_sem/1){+.+.}, at: tty_ldisc_lock_pair syzkaller/managers/linux-4-19/kernel/drivers/tty/tty_ldisc.c:397 [inline] #1: 0000000076112790 (&tty->ldisc_sem/1){+.+.}, at: tty_ldisc_release+0x354/0x440 syzkaller/managers/linux-4-19/kernel/drivers/tty/tty_ldisc.c:805 #2: 00000000eb219894 (rtnl_mutex){+.+.}, at: unregister_netdev+0xe/0x20 syzkaller/managers/linux-4-19/kernel/net/core/dev.c:9337 #3: 000000009241a1b5 (cpu_hotplug_lock.rw_sem){++++}, at: get_online_cpus syzkaller/managers/linux-4-19/kernel/./include/linux/cpu.h:137 [inline] #3: 000000009241a1b5 (cpu_hotplug_lock.rw_sem){++++}, at: flush_all_backlogs syzkaller/managers/linux-4-19/kernel/net/core/dev.c:5276 [inline] #3: 000000009241a1b5 (cpu_hotplug_lock.rw_sem){++++}, at: rollback_registered_many+0x3a8/0xe70 syzkaller/managers/linux-4-19/kernel/net/core/dev.c:8173 3 locks held by kworker/0:0/2247: #0: 0000000061e3b4db ((wq_completion)"%s"("ipv6_addrconf")){+.+.}, at: process_one_work+0x767/0x1570 syzkaller/managers/linux-4-19/kernel/kernel/workqueue.c:2126 #1: 000000003500e0e5 ((addr_chk_work).work){+.+.}, at: process_one_work+0x79c/0x1570 syzkaller/managers/linux-4-19/kernel/kernel/workqueue.c:2130 #2: 00000000eb219894 (rtnl_mutex){+.+.}, at: addrconf_verify_work+0xa/0x20 syzkaller/managers/linux-4-19/kernel/net/ipv6/addrconf.c:4476 1 lock held by syz-executor.5/31630: ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1567 Comm: khungtaskd Not tainted 4.19.172-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack syzkaller/managers/linux-4-19/kernel/lib/dump_stack.c:77 [inline] dump_stack+0x1fc/0x2ef syzkaller/managers/linux-4-19/kernel/lib/dump_stack.c:118 nmi_cpu_backtrace.cold+0x63/0xa2 syzkaller/managers/linux-4-19/kernel/lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1a6/0x1f0 syzkaller/managers/linux-4-19/kernel/lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace syzkaller/managers/linux-4-19/kernel/./include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks syzkaller/managers/linux-4-19/kernel/kernel/hung_task.c:203 [inline] watchdog+0x991/0xe60 syzkaller/managers/linux-4-19/kernel/kernel/hung_task.c:287 kthread+0x33f/0x460 syzkaller/managers/linux-4-19/kernel/kernel/kthread.c:259 ret_from_fork+0x24/0x30 syzkaller/managers/linux-4-19/kernel/arch/x86/entry/entry_64.S:415 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 31630 Comm: syz-executor.5 Not tainted 4.19.172-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:mddev_find+0x3f/0x770 syzkaller/managers/linux-4-19/kernel/drivers/md/md.c:588 Code: 31 ff 89 de e8 92 f6 ab fb 85 db 74 3f e8 19 f5 ab fb 89 d8 bf 09 00 00 00 c1 e8 14 41 89 c6 89 c6 89 44 24 08 e8 71 f6 ab fb <41> 83 fe 09 0f 84 97 02 00 00 e8 f2 f4 ab fb 83 e3 c0 89 d8 c1 e8 RSP: 0018:ffff88804c7ef7c0 EFLAGS: 00000297 RAX: 0000000000000002 RBX: 0000000000900000 RCX: ffffffff85b664bf RDX: 0000000000000009 RSI: ffff88804bb04500 RDI: 0000000000000005 RBP: ffff8880ab46b180 R08: 0000000000000000 R09: 0000000000000009 R10: 0000000000000005 R11: 0000000000000000 R12: ffff8880ab46b180 R13: ffff8880ab46b250 R14: 0000000000000009 R15: ffff8880ab46b198 FS: 00007fafe09b5700(0000) GS:ffff8880ba100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b2ef3f000 CR3: 000000008f596000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: md_open+0x3a/0x2a0 syzkaller/managers/linux-4-19/kernel/drivers/md/md.c:7448 __blkdev_get+0x372/0x1480 syzkaller/managers/linux-4-19/kernel/fs/block_dev.c:1494 blkdev_get+0xb0/0x940 syzkaller/managers/linux-4-19/kernel/fs/block_dev.c:1627 blkdev_open+0x202/0x290 syzkaller/managers/linux-4-19/kernel/fs/block_dev.c:1788 do_dentry_open+0x4aa/0x1160 syzkaller/managers/linux-4-19/kernel/fs/open.c:796 do_last syzkaller/managers/linux-4-19/kernel/fs/namei.c:3421 [inline] path_openat+0x793/0x2df0 syzkaller/managers/linux-4-19/kernel/fs/namei.c:3537 do_filp_open+0x18c/0x3f0 syzkaller/managers/linux-4-19/kernel/fs/namei.c:3567 do_sys_open+0x3b3/0x520 syzkaller/managers/linux-4-19/kernel/fs/open.c:1085 do_syscall_64+0xf9/0x620 syzkaller/managers/linux-4-19/kernel/arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x465b09 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fafe09b5188 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 000000000056bf60 RCX: 0000000000465b09 RDX: 0000000000000000 RSI: 00000000200001c0 RDI: ffffffffffffff9c RBP: 00000000004b069f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf60 R13: 00007ffe5afc6edf R14: 00007fafe09b5300 R15: 0000000000022000