INFO: task syz-executor.3:10855 blocked for more than 143 seconds. Not tainted 5.6.0-rc2-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.3 D23984 10855 1 0x00000004 Call Trace: context_switch kernel/sched/core.c:3380 [inline] __schedule+0x934/0x1f90 kernel/sched/core.c:4080 schedule+0xdc/0x2b0 kernel/sched/core.c:4154 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:4213 __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+0x279/0x4d0 fs/namei.c:1757 lookup_slow fs/namei.c:1774 [inline] walk_component+0x7ce/0x10b0 fs/namei.c:1915 link_path_walk.part.0+0x9d2/0x1370 fs/namei.c:2241 link_path_walk fs/namei.c:2766 [inline] path_mountpoint.isra.0+0x68/0x370 fs/namei.c:2766 filename_mountpoint+0x181/0x380 fs/namei.c:2792 user_path_mountpoint_at+0x3a/0x50 fs/namei.c:2822 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: 0033:0x45ee57 Code: 5c 24 40 4c 89 54 24 48 4c 89 4c 24 50 4c 89 44 24 58 48 89 7c 24 60 48 89 74 24 68 48 89 6c 24 70 48 89 5c 24 78 48 89 94 24 <80> 00 00 00 48 8b 94 24 90 00 00 00 48 89 8c 24 88 00 00 00 48 89 RSP: 002b:00007ffcf4bee418 EFLAGS: 00000202 ORIG_RAX: 00000000000000a6 RAX: ffffffffffffffda RBX: 0000000000071e2c RCX: 000000000045ee57 RDX: 0000000000403700 RSI: 0000000000000002 RDI: 00007ffcf4bee4c0 RBP: 000000000000034a R08: 0000000000000000 R09: 000000000000000c R10: 0000000000000006 R11: 0000000000000202 R12: 00007ffcf4bef550 R13: 000000000211d940 R14: 0000000000000000 R15: 00007ffcf4bef550 Showing all locks held in the system: 1 lock held by khungtaskd/1136: #0: ffffffff89bac240 (rcu_read_lock){....}, at: debug_show_all_locks+0x5f/0x279 kernel/locking/lockdep.c:5333 1 lock held by rsyslogd/10676: #0: ffff8880a94ab420 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xee/0x110 fs/file.c:821 2 locks held by getty/10797: #0: ffff88809e122090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc900018ab2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/10798: #0: ffff88808ec06090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc9000191b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/10799: #0: ffff88808ee2f090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc900018eb2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/10800: #0: ffff88808ec40090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc900018fb2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/10801: #0: ffff8880a2c18090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc9000188b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/10802: #0: ffff888097ecc090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc9000190b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/10803: #0: ffff8880a20e4090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc9000185b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by syz-executor.3/10855: #0: ffff888085cd81c0 (&type->i_mutex_dir_key#8){++++}, at: inode_lock_shared include/linux/fs.h:801 [inline] #0: ffff888085cd81c0 (&type->i_mutex_dir_key#8){++++}, at: lookup_slow fs/namei.c:1773 [inline] #0: ffff888085cd81c0 (&type->i_mutex_dir_key#8){++++}, at: walk_component+0x7b6/0x10b0 fs/namei.c:1915 #1: ffff888085cd8560 (&fi->mutex){+.+.}, at: fuse_lock_inode+0xba/0xf0 fs/fuse/inode.c:352 2 locks held by syz-executor.3/949: #0: ffff888085cd81c0 (&type->i_mutex_dir_key#8){++++}, at: inode_lock_shared include/linux/fs.h:801 [inline] #0: ffff888085cd81c0 (&type->i_mutex_dir_key#8){++++}, at: lookup_slow fs/namei.c:1773 [inline] #0: ffff888085cd81c0 (&type->i_mutex_dir_key#8){++++}, at: walk_component+0x7b6/0x10b0 fs/namei.c:1915 #1: ffff888085cd8560 (&fi->mutex){+.+.}, at: fuse_lock_inode+0xba/0xf0 fs/fuse/inode.c:352 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1136 Comm: khungtaskd Not tainted 5.6.0-rc2-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 skipped: idling at native_safe_halt+0xe/0x10 arch/x86/include/asm/irqflags.h:60