INFO: task syz-executor.5:9525 blocked for more than 143 seconds. Not tainted 5.5.0-rc2-next-20191220-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.5 D24080 9525 1 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 fuse_lock_inode+0xba/0xf0 fs/fuse/inode.c:352 fuse_lookup+0x8e/0x320 fs/fuse/dir.c:389 __lookup_slow+0x279/0x500 fs/namei.c:1757 lookup_slow+0x58/0x80 fs/namei.c:1774 walk_component+0x7a7/0x1060 fs/namei.c:1917 link_path_walk.part.0+0x9d2/0x1370 fs/namei.c:2243 link_path_walk fs/namei.c:2174 [inline] path_mountpoint+0xcf/0xe60 fs/namei.c:2834 filename_mountpoint+0x181/0x380 fs/namei.c:2857 user_path_mountpoint_at+0x3a/0x50 fs/namei.c:2887 ksys_umount+0x164/0xef0 fs/namespace.c:1683 __do_sys_umount fs/namespace.c:1709 [inline] __se_sys_umount fs/namespace.c:1707 [inline] __x64_sys_umount+0x54/0x80 fs/namespace.c:1707 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45d347 Code: Bad RIP value. RSP: 002b:00007ffd8b359868 EFLAGS: 00000202 ORIG_RAX: 00000000000000a6 RAX: ffffffffffffffda RBX: 000000000007dcdb RCX: 000000000045d347 RDX: 0000000000403720 RSI: 0000000000000002 RDI: 00007ffd8b359910 RBP: 0000000000000518 R08: 0000000000000000 R09: 000000000000000c R10: 0000000000000006 R11: 0000000000000202 R12: 00007ffd8b35a9a0 R13: 000000000277d940 R14: 0000000000000000 R15: 00007ffd8b35a9a0 Showing all locks held in the system: 3 locks held by kworker/u4:7/927: #0: ffff8880ae937518 (&rq->lock){-.-.}, at: nohz_newidle_balance kernel/sched/fair.c:10071 [inline] #0: ffff8880ae937518 (&rq->lock){-.-.}, at: newidle_balance+0x4aa/0xe80 kernel/sched/fair.c:10132 #1: ffffffff899af980 (rcu_read_lock){....}, at: __update_idle_core+0x45/0x3f0 kernel/sched/fair.c:5729 #2: ffff8880ae927418 (&base->lock){-.-.}, at: lock_timer_base+0x56/0x1b0 kernel/time/timer.c:936 1 lock held by khungtaskd/1117: #0: ffffffff899af980 (rcu_read_lock){....}, at: debug_show_all_locks+0x5f/0x279 kernel/locking/lockdep.c:5334 1 lock held by rsyslogd/9384: 2 locks held by getty/9474: #0: ffff88808b8f0090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc9000168b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9475: #0: ffff88809168c090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc900016af2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9476: #0: ffff888093b86090 (&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 getty/9477: #0: ffff888094d62090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc900016fb2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9478: #0: ffff888090220090 (&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/9479: #0: ffff8880a85c5090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc9000171b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9480: #0: ffff88821537e090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc900011442e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by syz-executor.5/9525: #0: ffff8880961cc240 (&type->i_mutex_dir_key#8){++++}, at: inode_lock_shared include/linux/fs.h:801 [inline] #0: ffff8880961cc240 (&type->i_mutex_dir_key#8){++++}, at: lookup_slow+0x4a/0x80 fs/namei.c:1773 #1: ffff8880961cc5e0 (&fi->mutex){+.+.}, at: fuse_lock_inode+0xba/0xf0 fs/fuse/inode.c:352 2 locks held by syz-executor.5/8639: #0: ffff8880961cc240 (&type->i_mutex_dir_key#8){++++}, at: inode_lock_shared include/linux/fs.h:801 [inline] #0: ffff8880961cc240 (&type->i_mutex_dir_key#8){++++}, at: lookup_slow+0x4a/0x80 fs/namei.c:1773 #1: ffff8880961cc5e0 (&fi->mutex){+.+.}, at: fuse_lock_inode+0xba/0xf0 fs/fuse/inode.c:352 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1117 Comm: khungtaskd Not tainted 5.5.0-rc2-next-20191220-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:249 [inline] watchdog+0xdf1/0x14e0 kernel/hung_task.c:333 kthread+0x361/0x430 kernel/kthread.c:255 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: 10986 Comm: kworker/1:8 Not tainted 5.5.0-rc2-next-20191220-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:__read_once_size include/linux/compiler.h:232 [inline] RIP: 0010:check_kcov_mode kernel/kcov.c:155 [inline] RIP: 0010:write_comp_data+0x17/0x70 kernel/kcov.c:208 Code: c2 01 48 39 d0 76 07 48 89 34 d1 48 89 11 5d c3 0f 1f 00 65 4c 8b 04 25 c0 1e 02 00 65 8b 05 98 c8 8c 7e a9 00 01 1f 00 75 51 <41> 8b 80 88 13 00 00 83 f8 03 75 45 49 8b 80 90 13 00 00 45 8b 80 RSP: 0018:ffffc900033e7af8 EFLAGS: 00000046 RAX: 0000000080000002 RBX: ffffc900033e7bd4 RCX: ffffffff83eb2fc7 RDX: 0000000000000006 RSI: 0000000000000008 RDI: 0000000000000005 RBP: ffffc900033e7b00 R08: ffff888053b74240 R09: fffff5200067cf4f R10: fffff5200067cf4e R11: 0000000000000003 R12: 0000000000000006 R13: dffffc0000000000 R14: ffff8880a84c9124 R15: ffff8880a84c9128 FS: 0000000000000000(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000001b35150 CR3: 00000000a2fc4000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: _crng_backtrack_protect+0xe7/0x140 drivers/char/random.c:1101 crng_backtrack_protect+0x65/0x80 drivers/char/random.c:1116 _get_random_bytes+0x19e/0x430 drivers/char/random.c:1719 get_random_bytes+0x35/0x40 drivers/char/random.c:1730 nsim_dev_trap_skb_build drivers/net/netdevsim/dev.c:349 [inline] nsim_dev_trap_report drivers/net/netdevsim/dev.c:373 [inline] nsim_dev_trap_report_work+0x6f2/0xaf0 drivers/net/netdevsim/dev.c:412 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