INIT: Entering runlevel: 2 [info] Using makefile-style concurrent boot in runlevel 2. [....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 Warning: Permanently added 'ci-upstream-net-kasan-gce-0,10.128.0.5' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 31.350116] refcount_t: underflow; use-after-free. [ 31.350971] ------------[ cut here ]------------ [ 31.351789] WARNING: CPU: 0 PID: 2922 at lib/refcount.c:186 refcount_sub_and_test+0x167/0x1b0 [ 31.352991] Kernel panic - not syncing: panic_on_warn set ... [ 31.352991] [ 31.353997] CPU: 0 PID: 2922 Comm: syzkaller973168 Not tainted 4.13.0-rc4+ #1 [ 31.354964] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 31.356238] Call Trace: [ 31.356613] dump_stack+0x194/0x257 [ 31.357140] ? arch_local_irq_restore+0x53/0x53 [ 31.357774] panic+0x1e4/0x417 [ 31.358283] ? __warn+0x1d9/0x1d9 [ 31.358754] ? show_regs_print_info+0x65/0x65 [ 31.359394] ? refcount_sub_and_test+0x167/0x1b0 [ 31.360024] __warn+0x1c4/0x1d9 [ 31.360466] ? refcount_sub_and_test+0x167/0x1b0 [ 31.361137] report_bug+0x211/0x2d0 [ 31.361702] fixup_bug+0x40/0x90 [ 31.362196] do_trap+0x260/0x390 [ 31.362675] do_error_trap+0x120/0x390 [ 31.363219] ? do_trap+0x390/0x390 [ 31.363698] ? refcount_sub_and_test+0x167/0x1b0 [ 31.364369] ? vprintk_emit+0x3ea/0x590 [ 31.364910] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 31.365558] do_invalid_op+0x1b/0x20 [ 31.366095] invalid_op+0x1e/0x30 [ 31.366560] RIP: 0010:refcount_sub_and_test+0x167/0x1b0 [ 31.367282] RSP: 0018:ffff8801d3be6310 EFLAGS: 00010282 [ 31.367992] RAX: 0000000000000026 RBX: 0000000000000001 RCX: 0000000000000000 [ 31.368964] RDX: 0000000000000026 RSI: 1ffff1003a77cc22 RDI: ffffed003a77cc56 [ 31.369935] RBP: ffff8801d3be63a0 R08: 0000000000000001 R09: 0000000000000000 [ 31.370887] R10: 0000000000000000 R11: 0000000000000000 R12: 1ffff1003a77cc63 [ 31.378125] R13: 00000000ffffff01 R14: 0000000000000100 R15: ffff8801d1927a3c [ 31.385384] ? refcount_inc+0x50/0x50 [ 31.389151] ? __sctp_outq_teardown+0xc7d/0x15a0 [ 31.393873] ? sctp_association_free+0x2d0/0x930 [ 31.398596] ? sctp_do_sm+0x28e7/0x6d90 [ 31.402535] ? sctp_primitive_SHUTDOWN+0xa0/0xd0 [ 31.407260] ? sctp_close+0x3c6/0x980 [ 31.411028] ? inet_release+0xed/0x1c0 [ 31.414898] sctp_wfree+0x183/0x620 [ 31.418497] ? __sctp_write_space+0x910/0x910 [ 31.422966] skb_release_head_state+0x124/0x200 [ 31.427606] skb_release_all+0x15/0x60 [ 31.431464] consume_skb+0x153/0x490 [ 31.435147] ? sctp_chunk_put+0x99/0x420 [ 31.439175] ? alloc_skb_with_frags+0x710/0x710 [ 31.443810] ? sctp_chunk_hold+0x20/0x20 [ 31.447844] ? refcount_sub_and_test+0x115/0x1b0 [ 31.452569] ? refcount_inc+0x50/0x50 [ 31.456345] ? mark_held_locks+0xaf/0x100 [ 31.460461] ? sctp_datamsg_put+0x456/0x560 [ 31.464754] sctp_chunk_put+0x29c/0x420 [ 31.468696] ? sctp_chunk_hold+0x20/0x20 [ 31.472727] ? sctp_transport_dst_confirm+0x50/0x50 [ 31.477715] ? noop_count+0x40/0x40 [ 31.481316] sctp_chunk_free+0x53/0x60 [ 31.485173] __sctp_outq_teardown+0xc7d/0x15a0 [ 31.489730] ? sctp_inq_set_th_handler+0x1b0/0x1b0 [ 31.494627] ? lock_downgrade+0x990/0x990 [ 31.498745] ? lock_release+0xa40/0xa40 [ 31.502690] ? __free_insn_slot+0x5c0/0x5c0 [ 31.507193] ? update_stack_state+0x700/0x700 [ 31.511655] ? print_usage_bug+0x480/0x480 [ 31.515866] ? is_bpf_text_address+0xa4/0x120 [ 31.520327] ? __kernel_text_address+0xae/0xe0 [ 31.524882] ? unwind_get_return_address+0x61/0xa0 [ 31.529795] ? __save_stack_trace+0x7e/0xd0 [ 31.534092] ? check_noncircular+0x20/0x20 [ 31.538293] ? print_usage_bug+0x480/0x480 [ 31.542493] ? SOFTIRQ_verbose+0x10/0x10 [ 31.546527] ? save_stack_trace+0x16/0x20 [ 31.550641] ? save_trace+0x11f/0x350 [ 31.554414] ? lock_acquire+0x1d5/0x580 [ 31.558351] ? lock_acquire+0x1d5/0x580 [ 31.562295] ? lock_timer_base+0x1a3/0x2b0 [ 31.566500] ? find_held_lock+0x35/0x1d0 [ 31.570546] ? sock_def_wakeup+0x1f9/0x350 [ 31.574751] ? lock_downgrade+0x990/0x990 [ 31.578868] ? lock_release+0xa40/0xa40 [ 31.582816] sctp_outq_free+0x15/0x20 [ 31.586583] sctp_association_free+0x2d0/0x930 [ 31.591136] ? sctp_asconf_queue_teardown+0x700/0x700 [ 31.596295] ? sock_def_wakeup+0x222/0x350 [ 31.600500] ? sk_dst_check+0x560/0x560 [ 31.604443] ? sctp_association_put+0x74/0x2f0 [ 31.609004] ? sctp_association_hold+0x20/0x20 [ 31.613556] ? print_usage_bug+0x480/0x480 [ 31.617769] ? sctp_sm_lookup_event+0x95/0x3c0 [ 31.622331] sctp_do_sm+0x28e7/0x6d90 [ 31.626103] ? check_noncircular+0x20/0x20 [ 31.630317] ? sctp_do_8_2_transport_strike.isra.16+0x8a0/0x8a0 [ 31.636347] ? print_usage_bug+0x480/0x480 [ 31.640549] ? exit_to_usermode_loop+0x21c/0x2d0 [ 31.645270] ? syscall_return_slowpath+0x3a7/0x450 [ 31.650169] ? print_usage_bug+0x480/0x480 [ 31.654369] ? find_held_lock+0x35/0x1d0 [ 31.658414] ? find_held_lock+0x35/0x1d0 [ 31.662536] ? skb_dequeue+0x12a/0x180 [ 31.666395] ? lock_downgrade+0x990/0x990 [ 31.670521] ? do_raw_spin_trylock+0x190/0x190 [ 31.675076] ? mark_held_locks+0xaf/0x100 [ 31.679198] ? trace_hardirqs_on+0xd/0x10 [ 31.683337] sctp_primitive_SHUTDOWN+0xa0/0xd0 [ 31.687893] sctp_close+0x3c6/0x980 [ 31.691496] ? sctp_apply_peer_addr_params+0xf30/0xf30 [ 31.696741] ? unwind_get_return_address+0x61/0xa0 [ 31.701640] ? retint_kernel+0x10/0x10 [ 31.705497] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 31.710482] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 31.715213] ? retint_kernel+0x10/0x10 [ 31.719073] ? ip_mc_drop_socket+0x1ce/0x230 [ 31.723453] inet_release+0xed/0x1c0 [ 31.727138] inet6_release+0x50/0x70 [ 31.730822] sock_release+0x8d/0x1e0 [ 31.734504] ? sock_release+0x1e0/0x1e0 [ 31.738485] sock_close+0x16/0x20 [ 31.741910] __fput+0x327/0x7e0 [ 31.745162] ? fput+0x140/0x140 [ 31.748412] ? do_raw_spin_trylock+0x190/0x190 [ 31.752969] ? check_same_owner+0x320/0x320 [ 31.757265] ____fput+0x15/0x20 [ 31.760518] task_work_run+0x18a/0x260 [ 31.764381] ? task_work_cancel+0x210/0x210 [ 31.768682] ? _raw_spin_unlock+0x22/0x30 [ 31.772801] ? switch_task_namespaces+0x87/0xc0 [ 31.777444] do_exit+0xa32/0x1b10 [ 31.780867] ? debug_check_no_locks_freed+0x3c0/0x3c0 [ 31.786035] ? print_usage_bug+0x480/0x480 [ 31.790250] ? exit_notify+0xb10/0xb10 [ 31.794108] ? check_noncircular+0x20/0x20 [ 31.798313] ? check_noncircular+0x20/0x20 [ 31.802522] ? find_held_lock+0x35/0x1d0 [ 31.806556] ? find_held_lock+0x35/0x1d0 [ 31.810601] ? check_noncircular+0x20/0x20 [ 31.814807] ? check_noncircular+0x20/0x20 [ 31.819012] ? lock_downgrade+0x990/0x990 [ 31.823136] ? do_raw_spin_trylock+0x190/0x190 [ 31.827689] ? reacquire_held_locks+0x1fd/0x3d0 [ 31.832322] ? mark_held_locks+0xaf/0x100 [ 31.836435] ? reacquire_held_locks+0x1fd/0x3d0 [ 31.841072] ? check_noncircular+0x20/0x20 [ 31.845275] ? find_held_lock+0x35/0x1d0 [ 31.849312] ? release_sock+0x1d4/0x2a0 [ 31.853261] ? lock_downgrade+0x990/0x990 [ 31.857375] ? lock_downgrade+0x990/0x990 [ 31.861503] ? find_held_lock+0x35/0x1d0 [ 31.865542] ? get_signal+0x855/0x17e0 [ 31.869398] ? lock_downgrade+0x990/0x990 [ 31.873523] do_group_exit+0x149/0x400 [ 31.877379] ? __lock_is_held+0xb6/0x140 [ 31.881409] ? SyS_exit+0x30/0x30 [ 31.884834] ? _raw_spin_unlock_irq+0x27/0x70 [ 31.889301] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 31.894289] get_signal+0x7e8/0x17e0 [ 31.897994] ? ptrace_notify+0x130/0x130 [ 31.902021] ? inet_autobind+0x1f/0x180 [ 31.905963] ? __local_bh_enable_ip+0x9d/0x160 [ 31.910514] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 31.915498] ? release_sock+0x1d4/0x2a0 [ 31.919438] ? trace_hardirqs_on+0xd/0x10 [ 31.923553] ? __local_bh_enable_ip+0x9d/0x160 [ 31.928106] ? _raw_spin_unlock_bh+0x30/0x40 [ 31.932482] ? release_sock+0x1d4/0x2a0 [ 31.936426] ? trace_hardirqs_on+0xd/0x10 [ 31.940546] do_signal+0x94/0x1ee0 [ 31.944070] ? inet_sendmsg+0x11f/0x5e0 [ 31.948008] ? inet_sendmsg+0x126/0x5e0 [ 31.951947] ? __might_sleep+0x95/0x190 [ 31.955891] ? setup_sigcontext+0x7d0/0x7d0 [ 31.960177] ? selinux_socket_sendmsg+0x36/0x40 [ 31.964815] ? security_socket_sendmsg+0x89/0xb0 [ 31.969545] ? inet_recvmsg+0x5f0/0x5f0 [ 31.973490] ? sock_sendmsg+0x4f/0x110 [ 31.977347] ? fput+0xd2/0x140 [ 31.980512] ? SYSC_sendto+0x40d/0x5a0 [ 31.984376] ? SYSC_connect+0x470/0x470 [ 31.988322] ? find_held_lock+0x35/0x1d0 [ 31.992359] ? exit_to_usermode_loop+0x98/0x2d0 [ 31.997004] exit_to_usermode_loop+0x21c/0x2d0 [ 32.001558] ? trace_event_raw_event_sys_exit+0x260/0x260 [ 32.007068] ? down_read_trylock+0xdb/0x170 [ 32.011359] ? __do_page_fault+0x2b8/0xb60 [ 32.015565] syscall_return_slowpath+0x3a7/0x450 [ 32.020288] ? prepare_exit_to_usermode+0x220/0x220 [ 32.025273] ? entry_SYSCALL_64_fastpath+0x91/0xbe [ 32.030169] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 32.035150] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 32.039890] entry_SYSCALL_64_fastpath+0xbc/0xbe [ 32.044610] RIP: 0033:0x445469 [ 32.047763] RSP: 002b:00007f841a455db8 EFLAGS: 00000212 ORIG_RAX: 000000000000002c [ 32.055437] RAX: 0000000000000006 RBX: 0000000000000000 RCX: 0000000000445469 [ 32.062671] RDX: 0000000000000006 RSI: 0000000020aa7000 RDI: 0000000000000003 [ 32.069912] RBP: 0000000000000000 R08: 0000000020aa7000 R09: 000000000000001c [ 32.077149] R10: 0000000000008000 R11: 0000000000000212 R12: 0000000000000000 [ 32.084385] R13: 00007ffff441b15f R14: 00007f841a4569c0 R15: 0000000000000000 [ 32.092019] Dumping ftrace buffer: [ 32.095575] (ftrace buffer empty) [ 32.099254] Kernel Offset: disabled [ 32.102847] Rebooting in 86400 seconds..