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-mmots-kasan-gce-2,10.128.0.14' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 31.123485] refcount_t: underflow; use-after-free. [ 31.128550] ------------[ cut here ]------------ [ 31.133393] WARNING: CPU: 1 PID: 2986 at lib/refcount.c:186 refcount_sub_and_test+0x167/0x1b0 [ 31.142049] Kernel panic - not syncing: panic_on_warn set ... [ 31.142049] [ 31.149379] CPU: 1 PID: 2986 Comm: syzkaller362982 Not tainted 4.13.0-mm1+ #7 [ 31.156617] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 31.165944] Call Trace: [ 31.168504] dump_stack+0x194/0x257 [ 31.172102] ? arch_local_irq_restore+0x53/0x53 [ 31.176753] panic+0x1e4/0x417 [ 31.179913] ? __warn+0x1d9/0x1d9 [ 31.183333] ? show_regs_print_info+0x65/0x65 [ 31.187810] ? refcount_sub_and_test+0x167/0x1b0 [ 31.192531] __warn+0x1c4/0x1d9 [ 31.195782] ? refcount_sub_and_test+0x167/0x1b0 [ 31.200512] report_bug+0x211/0x2d0 [ 31.204115] fixup_bug+0x40/0x90 [ 31.207451] do_trap+0x260/0x390 [ 31.210791] do_error_trap+0x120/0x390 [ 31.214653] ? do_trap+0x390/0x390 [ 31.218162] ? refcount_sub_and_test+0x167/0x1b0 [ 31.222885] ? vprintk_emit+0x3ea/0x590 [ 31.226839] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 31.231654] do_invalid_op+0x1b/0x20 [ 31.235337] invalid_op+0x18/0x20 [ 31.238760] RIP: 0010:refcount_sub_and_test+0x167/0x1b0 [ 31.244088] RSP: 0018:ffff8801ce016300 EFLAGS: 00010282 [ 31.249423] RAX: 0000000000000026 RBX: 0000000000000001 RCX: 0000000000000000 [ 31.256663] RDX: 0000000000000026 RSI: 1ffff10039c02c20 RDI: ffffed0039c02c54 [ 31.263900] RBP: ffff8801ce016390 R08: ffff8801ce0159f0 R09: 0000000000000000 [ 31.271138] R10: 0000000000000000 R11: 0000000000000000 R12: 1ffff10039c02c61 [ 31.278375] R13: 00000000ffffff01 R14: 0000000000000100 R15: ffff8801d28daae4 [ 31.285634] ? refcount_inc+0x50/0x50 [ 31.289404] ? __sctp_outq_teardown+0xc7d/0x15a0 [ 31.294126] ? sctp_association_free+0x2d0/0x930 [ 31.298848] ? sctp_do_sm+0x28e7/0x6dd0 [ 31.302791] ? sctp_primitive_SHUTDOWN+0xa0/0xd0 [ 31.307513] ? sctp_close+0x3c6/0x980 [ 31.311281] ? inet_release+0xed/0x1c0 [ 31.315147] sctp_wfree+0x183/0x620 [ 31.318745] ? __sctp_write_space+0x910/0x910 [ 31.323212] skb_release_head_state+0x124/0x200 [ 31.327849] skb_release_all+0x15/0x60 [ 31.331705] consume_skb+0x153/0x490 [ 31.335393] ? sctp_chunk_put+0x99/0x420 [ 31.339423] ? alloc_skb_with_frags+0x710/0x710 [ 31.344058] ? sctp_chunk_hold+0x20/0x20 [ 31.348099] ? refcount_sub_and_test+0x115/0x1b0 [ 31.352827] ? refcount_inc+0x50/0x50 [ 31.356595] ? mark_held_locks+0xb2/0x100 [ 31.360715] ? sctp_datamsg_put+0x456/0x560 [ 31.365017] sctp_chunk_put+0x29c/0x420 [ 31.368962] ? sctp_chunk_hold+0x20/0x20 [ 31.372998] ? sctp_transport_dst_confirm+0x50/0x50 [ 31.378000] sctp_chunk_free+0x53/0x60 [ 31.381857] __sctp_outq_teardown+0xc7d/0x15a0 [ 31.386407] ? inet6_release+0x50/0x70 [ 31.390270] ? sctp_inq_set_th_handler+0x1b0/0x1b0 [ 31.395169] ? unwind_next_frame.part.6+0x1ae/0xc70 [ 31.400156] ? unwind_next_frame.part.6+0x1ae/0xc70 [ 31.405140] ? unwind_dump+0x4c0/0x4c0 [ 31.408997] ? unwind_dump+0x4c0/0x4c0 [ 31.412856] ? copy_trace+0x1d0/0x1d0 [ 31.416630] ? check_noncircular+0x20/0x20 [ 31.420966] ? check_noncircular+0x20/0x20 [ 31.425176] ? unwind_get_return_address+0x61/0xa0 [ 31.430079] ? __save_stack_trace+0x61/0xd0 [ 31.434371] ? check_noncircular+0x20/0x20 [ 31.438578] ? print_usage_bug+0x480/0x480 [ 31.442788] ? find_held_lock+0x39/0x1d0 [ 31.446829] ? lock_downgrade+0x990/0x990 [ 31.450954] ? sk_dst_check+0x560/0x560 [ 31.454901] ? rcu_read_lock_sched_held+0x108/0x120 [ 31.459904] ? lock_release+0xd70/0xd70 [ 31.463861] sctp_outq_free+0x15/0x20 [ 31.467633] sctp_association_free+0x2d0/0x930 [ 31.472189] ? sctp_asconf_queue_teardown+0x700/0x700 [ 31.477348] ? sock_def_wakeup+0x222/0x350 [ 31.481553] ? sk_dst_check+0x560/0x560 [ 31.485498] ? sctp_association_put+0x74/0x2f0 [ 31.490048] ? sctp_association_hold+0x20/0x20 [ 31.494599] ? unwind_dump+0x4c0/0x4c0 [ 31.498460] ? sctp_sm_lookup_event+0x95/0x3c0 [ 31.503016] sctp_do_sm+0x28e7/0x6dd0 [ 31.506797] ? sctp_do_8_2_transport_strike.isra.16+0x8a0/0x8a0 [ 31.512827] ? print_usage_bug+0x480/0x480 [ 31.517029] ? __lock_acquire+0x20fd/0x4620 [ 31.521321] ? print_usage_bug+0x480/0x480 [ 31.525529] ? find_held_lock+0x39/0x1d0 [ 31.529570] ? lock_downgrade+0x990/0x990 [ 31.533693] ? skb_dequeue+0x22/0x180 [ 31.537470] ? do_raw_spin_trylock+0x190/0x190 [ 31.542025] ? mark_held_locks+0xb2/0x100 [ 31.546151] ? trace_hardirqs_on+0xd/0x10 [ 31.550276] sctp_primitive_SHUTDOWN+0xa0/0xd0 [ 31.554833] sctp_close+0x3c6/0x980 [ 31.558442] ? sctp_apply_peer_addr_params+0xf30/0xf30 [ 31.563687] ? unwind_get_return_address+0x61/0xa0 [ 31.568586] ? check_noncircular+0x20/0x20 [ 31.572795] ? depot_save_stack+0x3b5/0x490 [ 31.577092] ? ipv6_sock_ac_close+0x2e8/0x3e0 [ 31.581560] ? ipv6_sock_mc_close+0x148/0x1a0 [ 31.586023] ? ipv6_sock_ac_drop+0x580/0x580 [ 31.590399] ? ip_mc_drop_socket+0x1ce/0x230 [ 31.594778] ? __fsnotify_parent+0xb4/0x3a0 [ 31.599075] inet_release+0xed/0x1c0 [ 31.602762] inet6_release+0x50/0x70 [ 31.606445] sock_release+0x8d/0x1e0 [ 31.610127] ? sock_release+0x1e0/0x1e0 [ 31.614068] sock_close+0x16/0x20 [ 31.617492] __fput+0x333/0x7f0 [ 31.620746] ? fput+0x140/0x140 [ 31.623998] ? _raw_spin_unlock_irq+0x27/0x70 [ 31.628467] ____fput+0x15/0x20 [ 31.631738] task_work_run+0x199/0x270 [ 31.635596] ? task_work_cancel+0x210/0x210 [ 31.639888] ? _raw_spin_unlock+0x22/0x30 [ 31.644005] ? switch_task_namespaces+0x87/0xc0 [ 31.648648] do_exit+0xa52/0x1b40 [ 31.652072] ? print_usage_bug+0x480/0x480 [ 31.656288] ? mm_update_next_owner+0x930/0x930 [ 31.660928] ? find_held_lock+0x39/0x1d0 [ 31.664963] ? check_noncircular+0x20/0x20 [ 31.669166] ? check_noncircular+0x20/0x20 [ 31.673369] ? lock_downgrade+0x990/0x990 [ 31.677498] ? reacquire_held_locks+0x205/0x3d0 [ 31.682135] ? check_noncircular+0x20/0x20 [ 31.686339] ? find_held_lock+0x39/0x1d0 [ 31.690380] ? lock_downgrade+0x990/0x990 [ 31.694496] ? lock_downgrade+0x990/0x990 [ 31.698617] ? find_held_lock+0x39/0x1d0 [ 31.702657] ? lock_downgrade+0x990/0x990 [ 31.706775] ? recalc_sigpending_tsk+0x117/0x150 [ 31.711500] ? recalc_sigpending+0x103/0x160 [ 31.715880] ? recalc_sigpending_tsk+0x150/0x150 [ 31.720602] ? get_signal+0x397/0x17e0 [ 31.724469] do_group_exit+0x149/0x400 [ 31.728324] ? __lock_is_held+0xbc/0x140 [ 31.732353] ? SyS_exit+0x30/0x30 [ 31.735774] ? _raw_spin_unlock_irq+0x27/0x70 [ 31.740238] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 31.745228] get_signal+0x7e8/0x17e0 [ 31.748941] ? ptrace_notify+0x130/0x130 [ 31.752972] ? __local_bh_enable_ip+0x9d/0x160 [ 31.757525] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 31.762510] ? release_sock+0x1d4/0x2a0 [ 31.766453] ? trace_hardirqs_on+0xd/0x10 [ 31.770570] ? __local_bh_enable_ip+0x9d/0x160 [ 31.775121] ? _raw_spin_unlock_bh+0x30/0x40 [ 31.779497] ? release_sock+0x1d4/0x2a0 [ 31.783456] ? trace_hardirqs_on+0xd/0x10 [ 31.787580] do_signal+0x94/0x1ee0 [ 31.791093] ? inet_sendmsg+0x11f/0x5e0 [ 31.795033] ? inet_sendmsg+0x126/0x5e0 [ 31.798985] ? __might_sleep+0x95/0x190 [ 31.802933] ? setup_sigcontext+0x7d0/0x7d0 [ 31.807225] ? selinux_socket_sendmsg+0x36/0x40 [ 31.811863] ? security_socket_sendmsg+0x89/0xb0 [ 31.816624] ? inet_recvmsg+0x5f0/0x5f0 [ 31.820570] ? sock_sendmsg+0x4f/0x110 [ 31.824424] ? fput+0xd2/0x140 [ 31.827586] ? SYSC_sendto+0x413/0x5a0 [ 31.831445] ? SYSC_connect+0x480/0x480 [ 31.835387] ? __handle_mm_fault+0x39c0/0x39c0 [ 31.839947] ? exit_to_usermode_loop+0x98/0x300 [ 31.844591] exit_to_usermode_loop+0x224/0x300 [ 31.849145] ? trace_event_raw_event_sys_exit+0x260/0x260 [ 31.854655] ? __do_page_fault+0xb60/0xb60 [ 31.858861] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 31.863852] syscall_return_slowpath+0x42f/0x500 [ 31.868578] ? prepare_exit_to_usermode+0x2c0/0x2c0 [ 31.873565] ? entry_SYSCALL_64_fastpath+0x91/0xbe [ 31.878464] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 31.883449] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 31.888180] entry_SYSCALL_64_fastpath+0xbc/0xbe [ 31.892906] RIP: 0033:0x445429 [ 31.896065] RSP: 002b:00007fcf76eb7db8 EFLAGS: 00000212 ORIG_RAX: 000000000000002c [ 31.903743] RAX: 00000000000000d1 RBX: 0000000000000000 RCX: 0000000000445429 [ 31.910983] RDX: 00000000000000d1 RSI: 0000000020446000 RDI: 0000000000000003 [ 31.918221] RBP: 0000000000000000 R08: 0000000020e88000 R09: 0000000000000080 [ 31.925460] R10: 0000000000000010 R11: 0000000000000212 R12: 0000000000000000 [ 31.932708] R13: 00007ffe3693310f R14: 00007fcf76eb89c0 R15: 0000000000000000 [ 31.940668] Dumping ftrace buffer: [ 31.944223] (ftrace buffer empty) [ 31.947904] Kernel Offset: disabled [ 31.951508] Rebooting in 86400 seconds..