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-8,10.128.0.9' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 59.413982] refcount_t: underflow; use-after-free. [ 59.414901] ------------[ cut here ]------------ [ 59.415785] WARNING: CPU: 1 PID: 3008 at lib/refcount.c:186 refcount_sub_and_test+0x167/0x1b0 [ 59.416976] Kernel panic - not syncing: panic_on_warn set ... [ 59.416976] [ 59.418030] CPU: 1 PID: 3008 Comm: syzkaller474953 Not tainted 4.13.0-rc4+ #5 [ 59.418981] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 59.420198] Call Trace: [ 59.420554] dump_stack+0x194/0x257 [ 59.421045] ? arch_local_irq_restore+0x53/0x53 [ 59.421676] panic+0x1e4/0x417 [ 59.422119] ? __warn+0x1d9/0x1d9 [ 59.422581] ? show_regs_print_info+0x65/0x65 [ 59.423192] ? refcount_sub_and_test+0x167/0x1b0 [ 59.423833] __warn+0x1c4/0x1d9 [ 59.424274] ? refcount_sub_and_test+0x167/0x1b0 [ 59.424906] report_bug+0x211/0x2d0 [ 59.425412] fixup_bug+0x40/0x90 [ 59.425866] do_trap+0x260/0x390 [ 59.426342] do_error_trap+0x120/0x390 [ 59.426906] ? do_trap+0x390/0x390 [ 59.427392] ? refcount_sub_and_test+0x167/0x1b0 [ 59.428049] ? vprintk_emit+0x3ea/0x590 [ 59.428616] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 59.429267] do_invalid_op+0x1b/0x20 [ 59.429785] invalid_op+0x1e/0x30 [ 59.430247] RIP: 0010:refcount_sub_and_test+0x167/0x1b0 [ 59.430952] RSP: 0018:ffff8801d056e310 EFLAGS: 00010282 [ 59.431673] RAX: 0000000000000026 RBX: 0000000000000001 RCX: 0000000000000000 [ 59.432625] RDX: 0000000000000026 RSI: 1ffff1003a0adc22 RDI: ffffed003a0adc56 [ 59.433574] RBP: ffff8801d056e3a0 R08: 0000000000000001 R09: 0000000000000000 [ 59.437048] R10: 0000000000000000 R11: 0000000000000000 R12: 1ffff1003a0adc63 [ 59.444283] R13: 00000000ffffff01 R14: 0000000000000100 R15: ffff8801d054da3c [ 59.451547] ? refcount_inc+0x50/0x50 [ 59.455316] ? __sctp_outq_teardown+0xc7d/0x15a0 [ 59.460041] ? sctp_association_free+0x2d0/0x930 [ 59.464769] ? sctp_do_sm+0x28e7/0x6d90 [ 59.468711] ? sctp_primitive_SHUTDOWN+0xa0/0xd0 [ 59.473432] ? sctp_close+0x3c6/0x980 [ 59.477201] ? inet_release+0xed/0x1c0 [ 59.481059] sctp_wfree+0x183/0x620 [ 59.484654] ? __sctp_write_space+0x910/0x910 [ 59.489115] skb_release_head_state+0x124/0x200 [ 59.493771] skb_release_all+0x15/0x60 [ 59.497624] consume_skb+0x153/0x490 [ 59.501300] ? sctp_chunk_put+0x99/0x420 [ 59.505333] ? alloc_skb_with_frags+0x710/0x710 [ 59.509965] ? sctp_chunk_hold+0x20/0x20 [ 59.513996] ? refcount_sub_and_test+0x115/0x1b0 [ 59.518726] ? refcount_inc+0x50/0x50 [ 59.522489] ? mark_held_locks+0xaf/0x100 [ 59.526604] ? sctp_datamsg_put+0x456/0x560 [ 59.530895] sctp_chunk_put+0x29c/0x420 [ 59.534837] ? sctp_chunk_hold+0x20/0x20 [ 59.538869] ? sctp_transport_dst_confirm+0x50/0x50 [ 59.543854] ? noop_count+0x40/0x40 [ 59.547455] sctp_chunk_free+0x53/0x60 [ 59.551308] __sctp_outq_teardown+0xc7d/0x15a0 [ 59.555861] ? sctp_inq_set_th_handler+0x1b0/0x1b0 [ 59.560757] ? lock_downgrade+0x990/0x990 [ 59.564873] ? lock_release+0xa40/0xa40 [ 59.568816] ? __free_insn_slot+0x5c0/0x5c0 [ 59.573105] ? update_stack_state+0x700/0x700 [ 59.577563] ? print_usage_bug+0x480/0x480 [ 59.581774] ? is_bpf_text_address+0xa4/0x120 [ 59.586240] ? __kernel_text_address+0xae/0xe0 [ 59.590785] ? unwind_get_return_address+0x61/0xa0 [ 59.595681] ? __save_stack_trace+0x7e/0xd0 [ 59.599972] ? check_noncircular+0x20/0x20 [ 59.604171] ? print_usage_bug+0x480/0x480 [ 59.608370] ? SOFTIRQ_verbose+0x10/0x10 [ 59.612392] ? save_stack_trace+0x16/0x20 [ 59.616501] ? save_trace+0x11f/0x350 [ 59.620269] ? lock_acquire+0x1d5/0x580 [ 59.624205] ? lock_acquire+0x1d5/0x580 [ 59.628142] ? lock_timer_base+0x1a3/0x2b0 [ 59.632345] ? find_held_lock+0x35/0x1d0 [ 59.636382] ? sock_def_wakeup+0x1f9/0x350 [ 59.640584] ? lock_downgrade+0x990/0x990 [ 59.644697] ? lock_release+0xa40/0xa40 [ 59.648642] sctp_outq_free+0x15/0x20 [ 59.652408] sctp_association_free+0x2d0/0x930 [ 59.656958] ? sctp_asconf_queue_teardown+0x700/0x700 [ 59.662117] ? sock_def_wakeup+0x222/0x350 [ 59.666320] ? sk_dst_check+0x560/0x560 [ 59.670263] ? sctp_association_put+0x74/0x2f0 [ 59.674810] ? sctp_association_hold+0x20/0x20 [ 59.679356] ? print_usage_bug+0x480/0x480 [ 59.683564] ? sctp_sm_lookup_event+0x95/0x3c0 [ 59.688112] sctp_do_sm+0x28e7/0x6d90 [ 59.691876] ? check_noncircular+0x20/0x20 [ 59.696091] ? sctp_do_8_2_transport_strike.isra.16+0x8a0/0x8a0 [ 59.702117] ? print_usage_bug+0x480/0x480 [ 59.706316] ? exit_to_usermode_loop+0x224/0x300 [ 59.711034] ? syscall_return_slowpath+0x3a7/0x450 [ 59.715930] ? print_usage_bug+0x480/0x480 [ 59.720127] ? find_held_lock+0x35/0x1d0 [ 59.724181] ? find_held_lock+0x35/0x1d0 [ 59.728213] ? skb_dequeue+0x12a/0x180 [ 59.732063] ? lock_downgrade+0x990/0x990 [ 59.736178] ? do_raw_spin_trylock+0x190/0x190 [ 59.740727] ? mark_held_locks+0xaf/0x100 [ 59.744846] ? trace_hardirqs_on+0xd/0x10 [ 59.748966] sctp_primitive_SHUTDOWN+0xa0/0xd0 [ 59.753611] sctp_close+0x3c6/0x980 [ 59.757210] ? sctp_apply_peer_addr_params+0xf30/0xf30 [ 59.762449] ? unwind_get_return_address+0x61/0xa0 [ 59.767347] ? trace_hardirqs_off+0xd/0x10 [ 59.771547] ? _raw_spin_unlock_irqrestore+0xa6/0xba [ 59.776615] ? check_noncircular+0x20/0x20 [ 59.780824] ? ipv6_sock_ac_close+0x2e8/0x3e0 [ 59.785290] ? ipv6_sock_mc_close+0x148/0x1a0 [ 59.789762] ? ipv6_sock_ac_drop+0x580/0x580 [ 59.794137] ? ip_mc_drop_socket+0x1ce/0x230 [ 59.798522] ? __fsnotify_parent+0xb4/0x3a0 [ 59.802812] inet_release+0xed/0x1c0 [ 59.806498] inet6_release+0x50/0x70 [ 59.810176] sock_release+0x8d/0x1e0 [ 59.813854] ? sock_release+0x1e0/0x1e0 [ 59.817791] sock_close+0x16/0x20 [ 59.821218] __fput+0x327/0x7e0 [ 59.824471] ? fput+0x140/0x140 [ 59.827719] ? do_raw_spin_trylock+0x190/0x190 [ 59.832265] ? check_same_owner+0x320/0x320 [ 59.836553] ____fput+0x15/0x20 [ 59.839798] task_work_run+0x18a/0x260 [ 59.843652] ? task_work_cancel+0x210/0x210 [ 59.847939] ? _raw_spin_unlock+0x22/0x30 [ 59.852051] ? switch_task_namespaces+0x87/0xc0 [ 59.856690] do_exit+0xa3a/0x1b10 [ 59.860109] ? debug_check_no_locks_freed+0x3c0/0x3c0 [ 59.865267] ? print_usage_bug+0x480/0x480 [ 59.869471] ? mm_update_next_owner+0x930/0x930 [ 59.874104] ? check_noncircular+0x20/0x20 [ 59.878304] ? check_noncircular+0x20/0x20 [ 59.882510] ? find_held_lock+0x35/0x1d0 [ 59.886540] ? find_held_lock+0x35/0x1d0 [ 59.890580] ? check_noncircular+0x20/0x20 [ 59.894781] ? check_noncircular+0x20/0x20 [ 59.898984] ? lock_downgrade+0x990/0x990 [ 59.903101] ? do_raw_spin_trylock+0x190/0x190 [ 59.907650] ? reacquire_held_locks+0x1fd/0x3d0 [ 59.912281] ? mark_held_locks+0xaf/0x100 [ 59.916393] ? reacquire_held_locks+0x1fd/0x3d0 [ 59.921028] ? check_noncircular+0x20/0x20 [ 59.925231] ? find_held_lock+0x35/0x1d0 [ 59.929266] ? release_sock+0x1d4/0x2a0 [ 59.933204] ? lock_downgrade+0x990/0x990 [ 59.937313] ? lock_downgrade+0x990/0x990 [ 59.941430] ? find_held_lock+0x35/0x1d0 [ 59.945466] ? get_signal+0x855/0x17e0 [ 59.949318] ? lock_downgrade+0x990/0x990 [ 59.953437] do_group_exit+0x149/0x400 [ 59.957291] ? __lock_is_held+0xb6/0x140 [ 59.961322] ? SyS_exit+0x30/0x30 [ 59.964748] ? _raw_spin_unlock_irq+0x27/0x70 [ 59.969209] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 59.974195] get_signal+0x7e8/0x17e0 [ 59.977900] ? ptrace_notify+0x130/0x130 [ 59.981928] ? inet_autobind+0x1f/0x180 [ 59.985866] ? __local_bh_enable_ip+0x9d/0x160 [ 59.990414] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 59.995394] ? release_sock+0x1d4/0x2a0 [ 59.999337] ? trace_hardirqs_on+0xd/0x10 [ 60.003456] ? __local_bh_enable_ip+0x9d/0x160 [ 60.008006] ? _raw_spin_unlock_bh+0x30/0x40 [ 60.012380] ? release_sock+0x1d4/0x2a0 [ 60.016330] ? trace_hardirqs_on+0xd/0x10 [ 60.020447] do_signal+0x94/0x1ee0 [ 60.023957] ? inet_sendmsg+0x11f/0x5e0 [ 60.027893] ? inet_sendmsg+0x126/0x5e0 [ 60.031830] ? __might_sleep+0x95/0x190 [ 60.035772] ? setup_sigcontext+0x7d0/0x7d0 [ 60.040060] ? selinux_socket_sendmsg+0x36/0x40 [ 60.044695] ? security_socket_sendmsg+0x89/0xb0 [ 60.049417] ? inet_recvmsg+0x5f0/0x5f0 [ 60.053359] ? sock_sendmsg+0x4f/0x110 [ 60.057213] ? fput+0xd2/0x140 [ 60.060369] ? SYSC_sendto+0x40d/0x5a0 [ 60.064223] ? SYSC_connect+0x470/0x470 [ 60.068166] ? find_held_lock+0x35/0x1d0 [ 60.072200] ? exit_to_usermode_loop+0x98/0x300 [ 60.076844] exit_to_usermode_loop+0x224/0x300 [ 60.081397] ? trace_event_raw_event_sys_exit+0x260/0x260 [ 60.086905] ? handle_mm_fault+0x4e3/0x940 [ 60.091103] ? down_read_trylock+0xdb/0x170 [ 60.095395] syscall_return_slowpath+0x3a7/0x450 [ 60.100118] ? prepare_exit_to_usermode+0x220/0x220 [ 60.105099] ? entry_SYSCALL_64_fastpath+0x91/0xbe [ 60.109995] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 60.114979] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 60.119705] entry_SYSCALL_64_fastpath+0xbc/0xbe [ 60.124424] RIP: 0033:0x445429 [ 60.127581] RSP: 002b:00007fc80a63bdb8 EFLAGS: 00000212 ORIG_RAX: 000000000000002c [ 60.135264] RAX: 00000000000000d1 RBX: 0000000000000000 RCX: 0000000000445429 [ 60.142500] RDX: 00000000000000d1 RSI: 0000000020446000 RDI: 0000000000000003 [ 60.149739] RBP: 0000000000000000 R08: 0000000020e88000 R09: 0000000000000080 [ 60.156974] R10: 0000000000000010 R11: 0000000000000212 R12: 0000000000000000 [ 60.164218] R13: 00007ffc2e283b5f R14: 00007fc80a63c9c0 R15: 0000000000000000 [ 60.171647] Dumping ftrace buffer: [ 60.175200] (ftrace buffer empty) [ 60.178965] Kernel Offset: disabled [ 60.182562] Rebooting in 86400 seconds..