INFO: task kworker/1:47:2805 blocked for more than 143 seconds. Not tainted 5.5.0-rc6-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kworker/1:47 D26936 2805 2 0x80004000 Workqueue: events console_callback Call Trace: context_switch kernel/sched/core.c:3385 [inline] __schedule+0x934/0x1f90 kernel/sched/core.c:4081 schedule+0xdc/0x2b0 kernel/sched/core.c:4155 schedule_timeout+0x717/0xc50 kernel/time/timer.c:1871 __down_common kernel/locking/semaphore.c:220 [inline] __down+0x176/0x2c0 kernel/locking/semaphore.c:237 down+0x64/0x90 kernel/locking/semaphore.c:61 console_lock+0x29/0x80 kernel/printk/printk.c:2289 console_callback+0x70/0x400 drivers/tty/vt/vt.c:2818 process_one_work+0x9af/0x1740 kernel/workqueue.c:2264 worker_thread+0x98/0xe40 kernel/workqueue.c:2410 kthread+0x361/0x430 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 INFO: task syz-executor.2:24995 blocked for more than 143 seconds. Not tainted 5.5.0-rc6-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.2 D28312 24995 10662 0x00000004 Call Trace: context_switch kernel/sched/core.c:3385 [inline] __schedule+0x934/0x1f90 kernel/sched/core.c:4081 schedule+0xdc/0x2b0 kernel/sched/core.c:4155 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:4214 __mutex_lock_common kernel/locking/mutex.c:1033 [inline] __mutex_lock+0x7ab/0x13c0 kernel/locking/mutex.c:1103 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1118 lock_fb_info include/linux/fb.h:637 [inline] fb_open+0xd7/0x450 drivers/video/fbdev/core/fbmem.c:1406 chrdev_open+0x245/0x6b0 fs/char_dev.c:414 do_dentry_open+0x4e6/0x1380 fs/open.c:797 vfs_open+0xa0/0xd0 fs/open.c:914 do_last fs/namei.c:3356 [inline] path_openat+0x118b/0x3180 fs/namei.c:3473 do_filp_open+0x1a1/0x280 fs/namei.c:3503 do_sys_open+0x3fe/0x5d0 fs/open.c:1097 __do_sys_openat fs/open.c:1124 [inline] __se_sys_openat fs/open.c:1118 [inline] __x64_sys_openat+0x9d/0x100 fs/open.c:1118 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45aff9 Code: ad b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 0f 83 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007efd35bd9c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007efd35bda6d4 RCX: 000000000045aff9 RDX: 0000000000000000 RSI: 0000000020000180 RDI: ffffffffffffff9c RBP: 000000000075bfc8 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 000000000000076e R14: 00000000004c8974 R15: 000000000075bfd4 Showing all locks held in the system: 2 locks held by kworker/u4:6/660: 1 lock held by khungtaskd/1117: #0: ffffffff899a3f00 (rcu_read_lock){....}, at: debug_show_all_locks+0x5f/0x279 kernel/locking/lockdep.c:5334 2 locks held by kworker/1:47/2805: #0: ffff8880aa426d28 ((wq_completion)events){+.+.}, at: __write_once_size include/linux/compiler.h:226 [inline] #0: ffff8880aa426d28 ((wq_completion)events){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff8880aa426d28 ((wq_completion)events){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:855 [inline] #0: ffff8880aa426d28 ((wq_completion)events){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:40 [inline] #0: ffff8880aa426d28 ((wq_completion)events){+.+.}, at: set_work_data kernel/workqueue.c:615 [inline] #0: ffff8880aa426d28 ((wq_completion)events){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:642 [inline] #0: ffff8880aa426d28 ((wq_completion)events){+.+.}, at: process_one_work+0x88b/0x1740 kernel/workqueue.c:2235 #1: ffffc90008a37dc0 (console_work){+.+.}, at: process_one_work+0x8c1/0x1740 kernel/workqueue.c:2239 1 lock held by rsyslogd/10490: #0: ffff8880956ca3e0 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xee/0x110 fs/file.c:801 2 locks held by getty/10612: #0: ffff888097aca090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc9000177b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/10613: #0: ffff88809642c090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc9000176b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/10614: #0: ffff8880968a7090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc9000178b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/10615: #0: ffff8880978b1090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc900017932e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/10616: #0: ffff8880968a8090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc9000178f2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/10617: #0: ffff888097a2f090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc9000170b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/10618: #0: ffff888095c8a090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc900016eb2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by syz-executor.2/24987: 1 lock held by syz-executor.2/24995: #0: ffff8880a382f070 (&fb_info->lock){+.+.}, at: lock_fb_info include/linux/fb.h:637 [inline] #0: ffff8880a382f070 (&fb_info->lock){+.+.}, at: fb_open+0xd7/0x450 drivers/video/fbdev/core/fbmem.c:1406 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1117 Comm: khungtaskd Not tainted 5.5.0-rc6-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+0x197/0x210 lib/dump_stack.c:118 nmi_cpu_backtrace.cold+0x70/0xb2 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x23b/0x28b lib/nmi_backtrace.c:62 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:205 [inline] watchdog+0xb11/0x10c0 kernel/hung_task.c:289 kthread+0x361/0x430 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 4332 Comm: udevd Not tainted 5.5.0-rc6-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:check_memory_region+0x1f/0x1a0 mm/kasan/generic.c:191 Code: 00 66 2e 0f 1f 84 00 00 00 00 00 48 85 f6 0f 84 34 01 00 00 48 b8 ff ff ff ff ff 7f ff ff 55 0f b6 d2 48 39 c7 48 89 e5 41 55 <41> 54 53 0f 86 07 01 00 00 4c 8d 5c 37 ff 49 89 f8 48 b8 00 00 00 RSP: 0018:ffffc90001c1f8a0 EFLAGS: 00000012 RAX: ffff7fffffffffff RBX: 00000000000004c6 RCX: ffffffff815a7ee0 RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8b2f3d78 RBP: ffffc90001c1f8a8 R08: 1ffffffff165e7af R09: fffffbfff165e7b0 R10: ffff8880a64fac18 R11: ffff8880a64fa380 R12: 00000000cb98681d R13: ffffffff8a7b7ef0 R14: 0000000000000000 R15: 0000000000000001 FS: 00007f8ef8b667a0(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffff600400 CR3: 00000000a6476000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __kasan_check_read+0x11/0x20 mm/kasan/common.c:95 test_bit include/asm-generic/bitops/instrumented-non-atomic.h:110 [inline] hlock_class kernel/locking/lockdep.c:163 [inline] __lock_acquire+0x8a0/0x4a00 kernel/locking/lockdep.c:3952 lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4485 __mutex_lock_common kernel/locking/mutex.c:956 [inline] __mutex_lock+0x156/0x13c0 kernel/locking/mutex.c:1103 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1118 ep_scan_ready_list+0x7d4/0x9e0 fs/eventpoll.c:680 ep_send_events fs/eventpoll.c:1772 [inline] ep_poll+0x1f9/0xe60 fs/eventpoll.c:1909 do_epoll_wait+0x210/0x260 fs/eventpoll.c:2273 __do_sys_epoll_wait fs/eventpoll.c:2283 [inline] __se_sys_epoll_wait fs/eventpoll.c:2280 [inline] __x64_sys_epoll_wait+0x97/0xf0 fs/eventpoll.c:2280 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x7f8ef827a943 Code: 00 31 d2 48 29 c2 64 89 11 48 83 c8 ff eb ea 90 90 90 90 90 90 90 90 83 3d b5 dc 2a 00 00 75 13 49 89 ca b8 e8 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 34 c3 48 83 ec 08 e8 3b c4 00 00 48 89 04 24 RSP: 002b:00007fff13826b08 EFLAGS: 00000246 ORIG_RAX: 00000000000000e8 RAX: ffffffffffffffda RBX: 0000000000000bb8 RCX: 00007f8ef827a943 RDX: 0000000000000008 RSI: 00007fff13826c00 RDI: 000000000000000a RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000001 R10: 0000000000000bb8 R11: 0000000000000246 R12: 0000000000000003 R13: 0000000000000000 R14: 0000000000b136b0 R15: 0000000000ade030