kworker/dying (415) used greatest stack depth: 13960 bytes left kworker/dying (846) used greatest stack depth: 13896 bytes left INFO: task syz-executor4:9392 blocked for more than 140 seconds. Not tainted 4.19.0-rc6+ #262 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor4 D22664 9392 5501 0x00000004 Call Trace: context_switch kernel/sched/core.c:2825 [inline] __schedule+0x86c/0x1ed0 kernel/sched/core.c:3473 schedule+0xfe/0x460 kernel/sched/core.c:3517 exp_funnel_lock kernel/rcu/tree_exp.h:320 [inline] _synchronize_rcu_expedited+0xc68/0xfd0 kernel/rcu/tree_exp.h:667 synchronize_rcu_expedited+0x35/0xb0 kernel/rcu/tree_exp.h:795 synchronize_net+0x3b/0x60 net/core/dev.c:9012 packet_set_ring+0x286/0x1da0 net/packet/af_packet.c:4319 packet_release+0x6b5/0xda0 net/packet/af_packet.c:3000 __sock_release+0xd7/0x250 net/socket.c:579 sock_close+0x19/0x20 net/socket.c:1141 __fput+0x385/0xa30 fs/file_table.c:278 ____fput+0x15/0x20 fs/file_table.c:309 task_work_run+0x1e8/0x2a0 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:193 [inline] exit_to_usermode_loop+0x318/0x380 arch/x86/entry/common.c:166 prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline] syscall_return_slowpath arch/x86/entry/common.c:268 [inline] do_syscall_64+0x6be/0x820 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x411051 Code: 00 00 00 e8 91 a8 01 00 0f 0b e8 1a 8f 04 00 e9 c5 fe ff ff cc cc cc cc cc 64 48 8b 0c 25 f8 ff ff ff 48 3b 61 10 76 3d 48 83 28 48 89 6c 24 20 48 8d 6c 24 20 48 8b 44 24 30 48 8b 08 48 89 RSP: 002b:00007fff0bffacd0 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 0000000000000007 RCX: 0000000000411051 RDX: 0000000000000000 RSI: 0000000000731918 RDI: 0000000000000006 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 00007fff0bffabf0 R11: 0000000000000293 R12: 0000000000000000 R13: 0000000000000001 R14: 0000000000000488 R15: 0000000000000004 Showing all locks held in the system: 1 lock held by khungtaskd/983: #0: 00000000226b6a98 (rcu_read_lock){....}, at: debug_show_all_locks+0xd0/0x424 kernel/locking/lockdep.c:4435 1 lock held by rsyslogd/5272: #0: 000000008bee6138 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x1bb/0x200 fs/file.c:766 2 locks held by getty/5362: #0: 0000000014e0f0e5 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 0000000034358980 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/5363: #0: 00000000fe787e7d (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000193bcfa6 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/5364: #0: 000000007f7de415 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 000000008f6bc7b0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/5365: #0: 00000000f69cb5d3 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 000000002124f859 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/5366: #0: 0000000096effa54 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000b3db3973 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/5367: #0: 00000000693159d6 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 0000000034e9d573 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/5368: #0: 00000000bf344f12 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000196071b2 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by syz-executor4/9392: #0: 00000000bd42802e (&sb->s_type->i_mutex_key#11){+.+.}, at: inode_lock include/linux/fs.h:738 [inline] #0: 00000000bd42802e (&sb->s_type->i_mutex_key#11){+.+.}, at: __sock_release+0x8b/0x250 net/socket.c:578 #1: 00000000f9425448 (sk_lock-AF_PACKET){+.+.}, at: lock_sock include/net/sock.h:1491 [inline] #1: 00000000f9425448 (sk_lock-AF_PACKET){+.+.}, at: packet_release+0x5ff/0xda0 net/packet/af_packet.c:2992 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 983 Comm: khungtaskd Not tainted 4.19.0-rc6+ #262 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+0x1c4/0x2b4 lib/dump_stack.c:113 nmi_cpu_backtrace.cold.3+0x63/0xa2 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1b3/0x1ed 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+0xb3e/0x1050 kernel/hung_task.c:265 kthread+0x35a/0x420 kernel/kthread.c:246 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:413 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:57