9pnet: bogus RREADDIR count (149 > 25) 9pnet: bogus RREADDIR count (149 > 25) INFO: task syz-executor2:22380 blocked for more than 140 seconds. Not tainted 4.9.119-g9dc978d #23 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor2 D28288 22380 10935 0x00000004 ffff880197d28000 ffff8801d4534a80 ffff8801d4534a80 ffff880197d2b000 ffff8801db321c18 ffff8801a684fcc8 ffffffff839ebdcd ffff880197d288c8 ffffed0032fa5118 ffff880197d28000 00fffc0000000000 ffff8801db3224e8 Call Trace: [] schedule+0x7f/0x1b0 kernel/sched/core.c:3553 [] schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3586 [] __mutex_lock_common kernel/locking/mutex.c:582 [inline] [] mutex_lock_nested+0x326/0x870 kernel/locking/mutex.c:621 [] __fdget_pos+0xac/0xd0 fs/file.c:781 [] fdget_pos include/linux/file.h:66 [inline] [] SYSC_getdents64 fs/readdir.c:309 [inline] [] SyS_getdents64+0x115/0x280 fs/readdir.c:294 [] do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282 [] entry_SYSCALL_64_after_swapgs+0x5d/0xdb Showing all locks held in the system: 2 locks held by khungtaskd/519: #0: (rcu_read_lock){......}, at: [] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline] #0: (rcu_read_lock){......}, at: [] watchdog+0x11c/0xa20 kernel/hung_task.c:239 #1: (tasklist_lock){.+.?..}, at: [] debug_show_all_locks+0x79/0x218 kernel/locking/lockdep.c:4336 2 locks held by rs:main Q:Reg/3595: #0: (&f->f_pos_lock){+.+.+.}, at: [] __fdget_pos+0xac/0xd0 fs/file.c:781 #1: (sb_writers#3){.+.+.+}, at: [] file_start_write include/linux/fs.h:2640 [inline] #1: (sb_writers#3){.+.+.+}, at: [] vfs_write+0x3ae/0x530 fs/read_write.c:556 2 locks held by getty/3693: #0: (&tty->ldisc_sem){++++++}, at: [] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367 #1: (&ldata->atomic_read_lock){+.+...}, at: [] n_tty_read+0x202/0x16e0 drivers/tty/n_tty.c:2142 2 locks held by syz-executor2/22301: #0: (&f->f_pos_lock){+.+.+.}, at: [] __fdget_pos+0xac/0xd0 fs/file.c:781 #1: (&sb->s_type->i_mutex_key#19){++++++}, at: [] inode_lock_shared include/linux/fs.h:776 [inline] #1: (&sb->s_type->i_mutex_key#19){++++++}, at: [] iterate_dir+0xc3/0x600 fs/readdir.c:39 1 lock held by syz-executor2/22380: #0: (&f->f_pos_lock){+.+.+.}, at: [] __fdget_pos+0xac/0xd0 fs/file.c:781 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 519 Comm: khungtaskd Not tainted 4.9.119-g9dc978d #23 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 ffff8801d8877d08 ffffffff81eb4be9 0000000000000000 0000000000000001 0000000000000001 0000000000000001 ffffffff810b9bd0 ffff8801d8877d40 ffffffff81ebfee7 0000000000000001 0000000000000000 0000000000000003 Call Trace: [] __dump_stack lib/dump_stack.c:15 [inline] [] dump_stack+0xc1/0x128 lib/dump_stack.c:51 [] nmi_cpu_backtrace.cold.2+0x48/0x87 lib/nmi_backtrace.c:99 [] nmi_trigger_cpumask_backtrace+0x12a/0x14f lib/nmi_backtrace.c:60 [] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37 [] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline] [] check_hung_task kernel/hung_task.c:125 [inline] [] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline] [] watchdog+0x6b4/0xa20 kernel/hung_task.c:239 [] kthread+0x26d/0x300 kernel/kthread.c:211 [] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:373 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 skipped: idling at pc 0xffffffff839fb8d6