INFO: task syz-executor.4:7610 blocked for more than 140 seconds. Not tainted 5.0.0-rc7-next-20190222 #41 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.4 D23200 7610 1 0x00000004 Call Trace: context_switch kernel/sched/core.c:2877 [inline] __schedule+0x817/0x1cc0 kernel/sched/core.c:3518 schedule+0x92/0x180 kernel/sched/core.c:3562 __rwsem_down_write_failed_common kernel/locking/rwsem-xadd.c:582 [inline] rwsem_down_write_failed+0x774/0xc30 kernel/locking/rwsem-xadd.c:611 call_rwsem_down_write_failed+0x17/0x30 arch/x86/lib/rwsem.S:117 __down_write arch/x86/include/asm/rwsem.h:142 [inline] down_write+0x53/0x90 kernel/locking/rwsem.c:72 inode_lock include/linux/fs.h:763 [inline] vfs_unlink+0xd1/0x560 fs/namei.c:3989 do_unlinkat+0x3f7/0x6d0 fs/namei.c:4061 __do_sys_unlink fs/namei.c:4108 [inline] __se_sys_unlink fs/namei.c:4106 [inline] __x64_sys_unlink+0x42/0x50 fs/namei.c:4106 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x457b77 Code: 44 24 18 48 8b 4c 24 20 48 89 01 48 8b 6c 24 28 48 83 c4 30 c3 e8 49 23 00 00 eb 97 cc cc cc cc cc cc cc 64 48 8b 0c 25 f8 ff ff 48 3b 61 10 0f 86 b6 00 00 00 48 83 ec 40 48 89 6c 24 38 48 RSP: 002b:00007ffc728b5478 EFLAGS: 00000246 ORIG_RAX: 0000000000000057 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000457b77 RDX: 00007ffc728b5490 RSI: 00007ffc728b5490 RDI: 00007ffc728b5520 RBP: 0000000000000cb7 R08: 0000000000000000 R09: 0000000000000014 R10: 0000000000000005 R11: 0000000000000246 R12: 00007ffc728b6610 R13: 00000000012ee980 R14: 0000000000000000 R15: 0000000000000004 Showing all locks held in the system: 1 lock held by khungtaskd/1043: #0: 00000000e3923056 (rcu_read_lock){....}, at: debug_show_all_locks+0x5f/0x27e kernel/locking/lockdep.c:4382 1 lock held by rsyslogd/7472: #0: 00000000b448828b (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xee/0x110 fs/file.c:801 2 locks held by getty/7563: #0: 00000000b7eca331 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 000000009bca65f0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/7564: #0: 000000008fe31c11 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000d3ab137e (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/7565: #0: 000000003a9b0e3d (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 000000007537479a (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/7566: #0: 00000000e77320e4 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 0000000074f1cee6 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/7567: #0: 00000000d88fca71 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000d8e39986 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/7568: #0: 000000002f070d42 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000167cff51 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/7569: #0: 00000000c875263c (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000b037be37 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 3 locks held by syz-executor.4/7610: #0: 000000005c697b19 (sb_writers#3){.+.+}, at: sb_start_write include/linux/fs.h:1612 [inline] #0: 000000005c697b19 (sb_writers#3){.+.+}, at: mnt_want_write+0x3f/0xc0 fs/namespace.c:358 #1: 00000000a276e3db (&type->i_mutex_dir_key#3/1){+.+.}, at: inode_lock_nested include/linux/fs.h:798 [inline] #1: 00000000a276e3db (&type->i_mutex_dir_key#3/1){+.+.}, at: do_unlinkat+0x29f/0x6d0 fs/namei.c:4047 #2: 000000007a6abb57 (&sb->s_type->i_mutex_key#10){++++}, at: inode_lock include/linux/fs.h:763 [inline] #2: 000000007a6abb57 (&sb->s_type->i_mutex_key#10){++++}, at: vfs_unlink+0xd1/0x560 fs/namei.c:3989 2 locks held by syz-executor.4/18193: #0: 000000005c697b19 (sb_writers#3){.+.+}, at: file_start_write include/linux/fs.h:2816 [inline] #0: 000000005c697b19 (sb_writers#3){.+.+}, at: vfs_write+0x429/0x580 fs/read_write.c:548 #1: 000000007a6abb57 (&sb->s_type->i_mutex_key#10){++++}, at: inode_trylock include/linux/fs.h:783 [inline] #1: 000000007a6abb57 (&sb->s_type->i_mutex_key#10){++++}, at: ext4_file_write_iter+0x257/0x11a0 fs/ext4/file.c:232 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1043 Comm: khungtaskd Not tainted 5.0.0-rc7-next-20190222 #41 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+0x172/0x1f0 lib/dump_stack.c:113 nmi_cpu_backtrace.cold+0x63/0xa4 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1be/0x236 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:204 [inline] watchdog+0x9b2/0xeb0 kernel/hung_task.c:288 kthread+0x357/0x430 kernel/kthread.c:253 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352 Sending NMI from CPU 1 to CPUs 0: