9pnet: p9_errstr2errno: server reported unknown error 9pnet: p9_errstr2errno: server reported unknown error INFO: task syz-executor0:13438 blocked for more than 140 seconds. Not tainted 4.18.0-next-20180824+ #47 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor0 D24504 13438 4460 0x00000004 Call Trace: context_switch kernel/sched/core.c:2825 [inline] __schedule+0x87c/0x1df0 kernel/sched/core.c:3473 schedule+0xfb/0x450 kernel/sched/core.c:3517 __rwsem_down_write_failed_common+0x98b/0x1650 kernel/locking/rwsem-xadd.c:566 rwsem_down_write_failed+0xe/0x10 kernel/locking/rwsem-xadd.c:595 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+0xaa/0x130 kernel/locking/rwsem.c:72 inode_lock include/linux/fs.h:765 [inline] utimes_common.isra.1+0x45c/0x8e0 fs/utimes.c:90 do_utimes+0x1f7/0x380 fs/utimes.c:156 do_futimesat+0x249/0x350 fs/utimes.c:212 __do_sys_utimes fs/utimes.c:225 [inline] __se_sys_utimes fs/utimes.c:222 [inline] __x64_sys_utimes+0x59/0x80 fs/utimes.c:222 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x457089 Code: 08 e8 3b a9 fb ff 48 8b 44 24 20 48 8b 4c 24 18 48 8b 54 24 38 48 8b 7c 24 48 eb 8d 48 8b 6c 24 50 48 83 c4 58 c3 48 89 04 24 <48> 89 5c 24 08 e8 0d a9 fb ff 48 8b 44 24 40 48 8b 4c 24 48 48 8b RSP: 002b:00007ff3df16fc78 EFLAGS: 00000246 ORIG_RAX: 00000000000000eb RAX: ffffffffffffffda RBX: 00007ff3df1706d4 RCX: 0000000000457089 RDX: 0000000000000000 RSI: 00000000200001c0 RDI: 0000000020000180 RBP: 00000000009301e0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000004d6d40 R14: 00000000004ca125 R15: 0000000000000002 Showing all locks held in the system: 1 lock held by khungtaskd/776: #0: 00000000618d8a95 (rcu_read_lock){....}, at: debug_show_all_locks+0xd0/0x428 kernel/locking/lockdep.c:4436 1 lock held by rsyslogd/4321: #0: 00000000dc18f7e5 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x1bb/0x200 fs/file.c:766 2 locks held by getty/4412: #0: 000000004c0d423a (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:353 #1: 000000002d57f2ba (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4413: #0: 00000000f5a4996f (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:353 #1: 0000000030550d34 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4414: #0: 000000007b57b1b8 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:353 #1: 0000000049fc11b4 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4415: #0: 000000000b77a03d (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000ab329f1a (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4416: #0: 00000000dffb32f8 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:353 #1: 0000000086a954a8 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4417: #0: 00000000fc9b7473 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:353 #1: 000000009ce72dcd (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4418: #0: 000000003a59d7eb (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000c402127e (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by syz-executor0/13374: #0: 00000000a9f9730a (sb_writers#15){.+.+}, at: sb_start_write include/linux/fs.h:1598 [inline] #0: 00000000a9f9730a (sb_writers#15){.+.+}, at: mnt_want_write+0x3f/0xc0 fs/namespace.c:360 #1: 000000005c34580f (&sb->s_type->i_mutex_key#19){++++}, at: inode_lock include/linux/fs.h:765 [inline] #1: 000000005c34580f (&sb->s_type->i_mutex_key#19){++++}, at: utimes_common.isra.1+0x45c/0x8e0 fs/utimes.c:90 2 locks held by syz-executor0/13438: #0: 00000000a9f9730a (sb_writers#15){.+.+}, at: sb_start_write include/linux/fs.h:1598 [inline] #0: 00000000a9f9730a (sb_writers#15){.+.+}, at: mnt_want_write+0x3f/0xc0 fs/namespace.c:360 #1: 000000005c34580f (&sb->s_type->i_mutex_key#19){++++}, at: inode_lock include/linux/fs.h:765 [inline] #1: 000000005c34580f (&sb->s_type->i_mutex_key#19){++++}, at: utimes_common.isra.1+0x45c/0x8e0 fs/utimes.c:90 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 776 Comm: khungtaskd Not tainted 4.18.0-next-20180824+ #47 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+0x1c9/0x2b4 lib/dump_stack.c:113 nmi_cpu_backtrace.cold.3+0x48/0x88 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x151/0x192 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:144 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:204 [inline] watchdog+0xb39/0x1040 kernel/hung_task.c:265 kthread+0x35a/0x420 kernel/kthread.c:246 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:415 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 skipped: idling at native_safe_halt+0x6/0x10 arch/x86/include/asm/irqflags.h:56