kobject: 'loop5' (ffff8880a41c2520): fill_kobj_path: path = '/devices/virtual/block/loop5' kobject: 'loop0' (ffff8880a40262e0): kobject_uevent_env kobject: 'loop0' (ffff8880a40262e0): fill_kobj_path: path = '/devices/virtual/block/loop0' kobject: 'loop1' (ffff8880a4080be0): kobject_uevent_env kobject: 'loop1' (ffff8880a4080be0): fill_kobj_path: path = '/devices/virtual/block/loop1' INFO: task syz-executor.4:7170 blocked for more than 140 seconds. Not tainted 4.14.160-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.4 D29248 7170 7102 0x00000004 Call Trace: context_switch kernel/sched/core.c:2808 [inline] __schedule+0x7b8/0x1cd0 kernel/sched/core.c:3384 schedule+0x92/0x1c0 kernel/sched/core.c:3428 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3486 __mutex_lock_common kernel/locking/mutex.c:833 [inline] __mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 fb_open+0xb7/0x420 drivers/video/fbdev/core/fbmem.c:1468 chrdev_open+0x207/0x590 fs/char_dev.c:423 do_dentry_open+0x73b/0xeb0 fs/open.c:777 vfs_open+0x105/0x220 fs/open.c:891 do_last fs/namei.c:3425 [inline] path_openat+0x8bd/0x3f70 fs/namei.c:3566 do_filp_open+0x18e/0x250 fs/namei.c:3600 do_sys_open+0x2c5/0x430 fs/open.c:1084 SYSC_openat fs/open.c:1111 [inline] SyS_openat+0x30/0x40 fs/open.c:1105 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x45a919 RSP: 002b:00007efcd1633c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 000000000045a919 RDX: 0000000000000000 RSI: 0000000020000180 RDI: ffffffffffffff9c RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007efcd16346d4 R13: 00000000004c805c R14: 00000000004df300 R15: 00000000ffffffff Showing all locks held in the system: 1 lock held by khungtaskd/1044: #0: (tasklist_lock){.+.+}, at: [] debug_show_all_locks+0x7f/0x21f kernel/locking/lockdep.c:4544 1 lock held by rsyslogd/6932: #0: (&f->f_pos_lock){+.+.}, at: [] __fdget_pos+0xab/0xd0 fs/file.c:769 2 locks held by getty/7054: #0: (&tty->ldisc_sem){++++}, at: [] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376 #1: (&ldata->atomic_read_lock){+.+.}, at: [] n_tty_read+0x1e6/0x17d0 drivers/tty/n_tty.c:2156 2 locks held by getty/7055: #0: (&tty->ldisc_sem){++++}, at: [] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376 #1: (&ldata->atomic_read_lock){+.+.}, at: [] n_tty_read+0x1e6/0x17d0 drivers/tty/n_tty.c:2156 2 locks held by getty/7056: #0: (&tty->ldisc_sem){++++}, at: [] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376 #1: (&ldata->atomic_read_lock){+.+.}, at: [] n_tty_read+0x1e6/0x17d0 drivers/tty/n_tty.c:2156 2 locks held by getty/7057: #0: (&tty->ldisc_sem){++++}, at: [] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376 #1: (&ldata->atomic_read_lock){+.+.}, at: [] n_tty_read+0x1e6/0x17d0 drivers/tty/n_tty.c:2156 2 locks held by getty/7058: #0: (&tty->ldisc_sem){++++}, at: [] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376 #1: (&ldata->atomic_read_lock){+.+.}, at: [] n_tty_read+0x1e6/0x17d0 drivers/tty/n_tty.c:2156 2 locks held by getty/7059: #0: (&tty->ldisc_sem){++++}, at: [] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376 #1: (&ldata->atomic_read_lock){+.+.}, at: [] n_tty_read+0x1e6/0x17d0 drivers/tty/n_tty.c:2156 2 locks held by getty/7060: #0: (&tty->ldisc_sem){++++}, at: [] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376 #1: (&ldata->atomic_read_lock){+.+.}, at: [] n_tty_read+0x1e6/0x17d0 drivers/tty/n_tty.c:2156 1 lock held by syz-executor.4/7170: #0: (&fb_info->lock){+.+.}, at: [] fb_open+0xb7/0x420 drivers/video/fbdev/core/fbmem.c:1468 1 lock held by syz-executor.4/7177: #0: (&fb_info->lock){+.+.}, at: [] fb_open+0xb7/0x420 drivers/video/fbdev/core/fbmem.c:1468 1 lock held by syz-executor.2/7188: #0: (&fb_info->lock){+.+.}, at: [] fb_open+0xb7/0x420 drivers/video/fbdev/core/fbmem.c:1468 1 lock held by syz-executor.2/7189: #0: (&fb_info->lock){+.+.}, at: [] fb_open+0xb7/0x420 drivers/video/fbdev/core/fbmem.c:1468 1 lock held by syz-executor.5/7195: #0: (&fb_info->lock){+.+.}, at: [] fb_open+0xb7/0x420 drivers/video/fbdev/core/fbmem.c:1468 1 lock held by syz-executor.5/7198: #0: (&fb_info->lock){+.+.}, at: [] fb_open+0xb7/0x420 drivers/video/fbdev/core/fbmem.c:1468 1 lock held by syz-executor.0/7201: #0: (&fb_info->lock){+.+.}, at: [] fb_open+0xb7/0x420 drivers/video/fbdev/core/fbmem.c:1468 1 lock held by syz-executor.0/7207: #0: (&fb_info->lock){+.+.}, at: [] fb_open+0xb7/0x420 drivers/video/fbdev/core/fbmem.c:1468 1 lock held by syz-executor.1/7206: #0: (&fb_info->lock){+.+.}, at: [] fb_open+0xb7/0x420 drivers/video/fbdev/core/fbmem.c:1468 1 lock held by syz-executor.1/7208: #0: (&fb_info->lock){+.+.}, at: [] fb_open+0xb7/0x420 drivers/video/fbdev/core/fbmem.c:1468 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1044 Comm: khungtaskd Not tainted 4.14.160-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x142/0x197 lib/dump_stack.c:58 nmi_cpu_backtrace.cold+0x57/0x94 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x141/0x189 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:140 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:195 [inline] watchdog+0x5e7/0xb90 kernel/hung_task.c:274 kthread+0x319/0x430 kernel/kthread.c:232 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 7156 Comm: kworker/u4:5 Not tainted 4.14.160-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: bat_events batadv_nc_worker task: ffff8880a8558300 task.stack: ffff8880791d8000 RIP: 0010:mark_lock+0xab/0x1240 kernel/locking/lockdep.c:3164 RSP: 0018:ffff8880791df9b8 EFLAGS: 00000046 RAX: dffffc0000000000 RBX: ffffffff89618c70 RCX: 1ffff110150ab17e RDX: 1ffffffff12c3194 RSI: ffff8880a8558bd0 RDI: ffffffff89618ca0 RBP: ffff8880791dfa00 R08: 0000000000000001 R09: ffff8880a8558bf0 R10: ffff8880a8558bd0 R11: ffff8880a8558300 R12: ffff8880a8558bd0 R13: 0000000000000004 R14: 0000000000000002 R15: ffff8880a8558300 FS: 0000000000000000(0000) GS:ffff8880aec00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f9db61e8008 CR3: 00000000a4db0000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: mark_irqflags kernel/locking/lockdep.c:3082 [inline] __lock_acquire+0xbcf/0x4620 kernel/locking/lockdep.c:3444 lock_acquire+0x16f/0x430 kernel/locking/lockdep.c:3994 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:135 [inline] _raw_spin_lock_bh+0x33/0x50 kernel/locking/spinlock.c:176 spin_lock_bh include/linux/spinlock.h:322 [inline] batadv_nc_purge_paths+0xcb/0x360 net/batman-adv/network-coding.c:450 batadv_nc_worker+0x270/0x6d0 net/batman-adv/network-coding.c:729 process_one_work+0x863/0x1600 kernel/workqueue.c:2114 worker_thread+0x5d9/0x1050 kernel/workqueue.c:2248 kthread+0x319/0x430 kernel/kthread.c:232 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404 Code: 50 01 00 00 48 81 eb 50 01 00 00 48 81 c3 80 7a 5a 89 48 8d 7b 30 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 <0f> 85 60 0d 00 00 4c 85 6b 30 0f 84 a8 00 00 00 41 bd 01 00 00