INFO: task syz-executor0:24195 blocked for more than 140 seconds. Not tainted 4.20.0-rc4+ #351 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor0 D24800 24195 6045 0x00000004 Call Trace: context_switch kernel/sched/core.c:2831 [inline] __schedule+0x8cf/0x21d0 kernel/sched/core.c:3472 schedule+0xfe/0x460 kernel/sched/core.c:3516 d_wait_lookup fs/dcache.c:2408 [inline] d_alloc_parallel+0x1478/0x1f40 fs/dcache.c:2490 lookup_open+0x560/0x1b90 fs/namei.c:3147 do_last fs/namei.c:3324 [inline] path_openat+0x2464/0x5150 fs/namei.c:3534 do_filp_open+0x255/0x380 fs/namei.c:3564 do_sys_open+0x568/0x700 fs/open.c:1063 __do_sys_openat fs/open.c:1090 [inline] __se_sys_openat fs/open.c:1084 [inline] __x64_sys_openat+0x9d/0x100 fs/open.c:1084 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x457569 Code: Bad RIP value. RSP: 002b:00007f6baff9ec78 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 0000000000457569 RDX: 0000000000000002 RSI: 0000000020000200 RDI: 0000000000000004 RBP: 000000000072c040 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f6baff9f6d4 R13: 00000000004c2e2f R14: 00000000004d4d98 R15: 00000000ffffffff Showing all locks held in the system: 1 lock held by khungtaskd/1020: #0: 0000000001571a5d (rcu_read_lock){....}, at: debug_show_all_locks+0xd0/0x424 kernel/locking/lockdep.c:4379 1 lock held by rsyslogd/5915: #0: 00000000480251dc (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x1bb/0x200 fs/file.c:766 2 locks held by getty/6005: #0: 000000003681f27e (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 0000000064b5f113 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 2 locks held by getty/6006: #0: 00000000cc777edb (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000ed08ef34 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 2 locks held by getty/6007: #0: 0000000064a5a3bc (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000133762dc (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 2 locks held by getty/6008: #0: 000000008dbc47bc (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 0000000061f43b82 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 2 locks held by getty/6009: #0: 00000000ffe2b59e (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 0000000029194069 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 2 locks held by getty/6010: #0: 0000000024096952 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000c5490d89 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 2 locks held by getty/6011: #0: 000000008a1359c1 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000a7a55aae (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 4 locks held by syz-executor0/24155: 2 locks held by syz-executor0/24195: #0: 000000008a424498 (sb_writers#14){.+.+}, at: sb_start_write include/linux/fs.h:1597 [inline] #0: 000000008a424498 (sb_writers#14){.+.+}, at: mnt_want_write+0x3f/0xc0 fs/namespace.c:360 #1: 0000000090e76042 (&sb->s_type->i_mutex_key#23){++++}, at: inode_lock_shared include/linux/fs.h:767 [inline] #1: 0000000090e76042 (&sb->s_type->i_mutex_key#23){++++}, at: do_last fs/namei.c:3323 [inline] #1: 0000000090e76042 (&sb->s_type->i_mutex_key#23){++++}, at: path_openat+0x2444/0x5150 fs/namei.c:3534 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1020 Comm: khungtaskd Not tainted 4.20.0-rc4+ #351 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+0x244/0x39d lib/dump_stack.c:113 nmi_cpu_backtrace.cold.2+0x5c/0xa1 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1e8/0x22a 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+0xb51/0x1060 kernel/hung_task.c:289 kthread+0x35a/0x440 kernel/kthread.c:246 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 3715 Comm: udevd Not tainted 4.20.0-rc4+ #351 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:__x86_indirect_thunk_rax+0x0/0x20 Code: 0c c8 e9 ee 01 d9 ff 41 bf f2 ff ff ff 45 30 ed e9 92 06 d9 ff 41 bf f2 ff ff ff e9 a5 06 d9 ff 90 90 90 90 90 90 90 90 90 90 07 00 00 00 f3 90 0f ae e8 eb f9 48 89 04 24 c3 0f 1f 44 00 00 RSP: 0018:ffff8881c2ebfe28 EFLAGS: 00000246 RAX: ffffffff81e63640 RBX: 00000000000000e8 RCX: ffffffff8100c3eb RDX: 1ffffffff104099c RSI: ffffffff8100c3f9 RDI: ffff8881c2ebff58 RBP: ffff8881c2ebff48 R08: ffff8881c2eb2100 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 1ffff110385d7fc8 R13: ffff8881c2ebff20 R14: ffff8881c2ebff58 R15: dffffc0000000000 FS: 00007f3d94df97a0(0000) GS:ffff8881daf00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffff600400 CR3: 00000001c2d60000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x7f3d9450d943 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:00007ffcc6fa6208 EFLAGS: 00000246 ORIG_RAX: 00000000000000e8 RAX: ffffffffffffffda RBX: 0000000000000bb8 RCX: 00007f3d9450d943 RDX: 0000000000000008 RSI: 00007ffcc6fa6300 RDI: 000000000000000a RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000001 R10: 0000000000000bb8 R11: 0000000000000246 R12: 0000000000000003 R13: 0000000000000000 R14: 0000000002019a90 R15: 0000000002018250