INFO: task syz-executor0:19518 blocked for more than 120 seconds. Not tainted 4.14.0-rc1+ #54 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor0 D24096 19518 3031 0x00000004 Call Trace: context_switch kernel/sched/core.c:2790 [inline] __schedule+0x8e8/0x2070 kernel/sched/core.c:3366 schedule+0x108/0x440 kernel/sched/core.c:3425 __lock_sock+0x1dc/0x2f0 net/core/sock.c:2235 lock_sock_nested+0xf3/0x110 net/core/sock.c:2756 lock_sock include/net/sock.h:1459 [inline] inet_shutdown+0x62/0x350 net/ipv4/af_inet.c:815 SYSC_shutdown net/socket.c:1904 [inline] SyS_shutdown+0x137/0x290 net/socket.c:1895 entry_SYSCALL_64_fastpath+0x1f/0xbe RIP: 0033:0x4520a9 RSP: 002b:00007f4a02319c08 EFLAGS: 00000216 ORIG_RAX: 0000000000000030 RAX: ffffffffffffffda RBX: 00000000007180b0 RCX: 00000000004520a9 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000006 RBP: 0000000000000082 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000216 R12: 00000000004b7fd1 R13: 00000000ffffffff R14: 0000000020738000 R15: 0000000000001000 Showing all locks held in the system: 2 locks held by khungtaskd/643: #0: (rcu_read_lock){....}, at: [] check_hung_uninterruptible_tasks kernel/hung_task.c:175 [inline] #0: (rcu_read_lock){....}, at: [] watchdog+0x1c5/0xd60 kernel/hung_task.c:249 #1: (tasklist_lock){.+.+}, at: [] debug_show_all_locks+0xd2/0x410 kernel/locking/lockdep.c:4552 2 locks held by getty/2955: #0: (&tty->ldisc_sem){++++}, at: [] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:367 #1: (&ldata->atomic_read_lock){+.+.}, at: [] n_tty_read+0x2f2/0x1a40 drivers/tty/n_tty.c:2133 2 locks held by getty/2956: #0: (&tty->ldisc_sem){++++}, at: [] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:367 #1: (&ldata->atomic_read_lock){+.+.}, at: [] n_tty_read+0x2f2/0x1a40 drivers/tty/n_tty.c:2133 2 locks held by getty/2957: #0: (&tty->ldisc_sem){++++}, at: [] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:367 #1: (&ldata->atomic_read_lock){+.+.}, at: [] n_tty_read+0x2f2/0x1a40 drivers/tty/n_tty.c:2133 2 locks held by getty/2958: #0: (&tty->ldisc_sem){++++}, at: [] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:367 #1: (&ldata->atomic_read_lock){+.+.}, at: [] n_tty_read+0x2f2/0x1a40 drivers/tty/n_tty.c:2133 2 locks held by getty/2959: #0: (&tty->ldisc_sem){++++}, at: [] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:367 #1: (&ldata->atomic_read_lock){+.+.}, at: [] n_tty_read+0x2f2/0x1a40 drivers/tty/n_tty.c:2133 2 locks held by getty/2960: #0: (&tty->ldisc_sem){++++}, at: [] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:367 #1: (&ldata->atomic_read_lock){+.+.}, at: [] n_tty_read+0x2f2/0x1a40 drivers/tty/n_tty.c:2133 2 locks held by getty/2961: #0: (&tty->ldisc_sem){++++}, at: [] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:367 #1: (&ldata->atomic_read_lock){+.+.}, at: [] n_tty_read+0x2f2/0x1a40 drivers/tty/n_tty.c:2133 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 643 Comm: khungtaskd Not tainted 4.14.0-rc1+ #54 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:16 [inline] dump_stack+0x194/0x257 lib/dump_stack.c:52 nmi_cpu_backtrace+0x20e/0x240 lib/nmi_backtrace.c:102 nmi_trigger_cpumask_backtrace+0x122/0x180 lib/nmi_backtrace.c:61 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37 trigger_all_cpu_backtrace include/linux/nmi.h:105 [inline] check_hung_task kernel/hung_task.c:132 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:190 [inline] watchdog+0x90c/0xd60 kernel/hung_task.c:249 kthread+0x39c/0x470 kernel/kthread.c:231 ret_from_fork+0x2a/0x40 arch/x86/entry/entry_64.S:431 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 19502 Comm: syz-executor0 Not tainted 4.14.0-rc1+ #54 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: ffff8801a40f6500 task.stack: ffff8801c9f88000 RIP: 0010:__lock_acquire+0x594/0x4620 kernel/locking/lockdep.c:3448 RSP: 0018:ffff8801c9f8ea28 EFLAGS: 00000002 RAX: 0000000000000002 RBX: ffff8801a40f6dc8 RCX: 0000000000000002 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff8801a40f6dec RBP: ffff8801c9f8ef28 R08: 0000000000000001 R09: 0000000000000002 R10: 0000000000000000 R11: ffffffff87060ca0 R12: ffff8801a40f6500 R13: 0000000000000028 R14: 0000000000000000 R15: ffff8801a40f6de0 FS: 00007f4a0233b700(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000001a96cd8 CR3: 00000001c323d000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: lock_acquire+0x1d5/0x580 kernel/locking/lockdep.c:4002 rcu_lock_acquire include/linux/rcupdate.h:244 [inline] rcu_read_lock include/linux/rcupdate.h:630 [inline] is_bpf_text_address+0x39/0x120 kernel/bpf/core.c:455 __kernel_text_address+0xae/0xe0 kernel/extable.c:113 unwind_get_return_address+0x61/0xa0 arch/x86/kernel/unwind_frame.c:18 __save_stack_trace+0x7e/0xd0 arch/x86/kernel/stacktrace.c:45 save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59 save_stack+0x43/0xd0 mm/kasan/kasan.c:447 set_track mm/kasan/kasan.c:459 [inline] kasan_kmalloc+0xad/0xe0 mm/kasan/kasan.c:551 __do_kmalloc_node mm/slab.c:3689 [inline] __kmalloc_node_track_caller+0x47/0x70 mm/slab.c:3703 __kmalloc_reserve.isra.40+0x41/0xd0 net/core/skbuff.c:138 __alloc_skb+0x13b/0x740 net/core/skbuff.c:206 alloc_skb include/linux/skbuff.h:976 [inline] _sctp_make_chunk+0x3b/0x260 net/sctp/sm_make_chunk.c:1383 sctp_make_data net/sctp/sm_make_chunk.c:1415 [inline] sctp_make_datafrag_empty+0x221/0x370 net/sctp/sm_make_chunk.c:738 sctp_datamsg_from_user+0x765/0x1150 net/sctp/chunk.c:266 sctp_sendmsg+0x1e87/0x3200 net/sctp/socket.c:1965 inet_sendmsg+0x11f/0x5e0 net/ipv4/af_inet.c:762 sock_sendmsg_nosec net/socket.c:633 [inline] sock_sendmsg+0xca/0x110 net/socket.c:643 SYSC_sendto+0x358/0x5a0 net/socket.c:1750 SyS_sendto+0x40/0x50 net/socket.c:1718 entry_SYSCALL_64_fastpath+0x1f/0xbe RIP: 0033:0x4520a9 RSP: 002b:00007f4a0233ac08 EFLAGS: 00000216 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 0000000000718000 RCX: 00000000004520a9 RDX: 00000000000000d1 RSI: 0000000020aaff09 RDI: 0000000000000006 RBP: 0000000000000082 R08: 0000000020ab0000 R09: 000000000000001c R10: 0000000020008004 R11: 0000000000000216 R12: 00000000004bfd20 R13: 00000000ffffffff R14: 0000000000000006 R15: 0000000000000084 Code: c1 e0 02 44 88 53 21 83 e1 f8 09 d1 09 c1 42 8d 04 cd 00 00 00 00 83 e1 f7 41 89 c9 41 09 c1 44 88 4b 22 0f b7 55 20 0f b7 43 22 e2 04 83 e0 0f 09 d0 48 89 fa 66 89 43 22 48 c1 ea 03 48 b8