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-6,10.128.15.192' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 30.225578] refcount_t: underflow; use-after-free. [ 30.230705] ------------[ cut here ]------------ [ 30.236141] WARNING: CPU: 0 PID: 2985 at lib/refcount.c:186 refcount_sub_and_test+0x167/0x1b0 [ 30.244985] Kernel panic - not syncing: panic_on_warn set ... [ 30.244985] [ 30.252319] CPU: 0 PID: 2985 Comm: syzkaller822718 Not tainted 4.13.0-mm1+ #7 [ 30.259561] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 30.268883] Call Trace: [ 30.271446] dump_stack+0x194/0x257 [ 30.275046] ? arch_local_irq_restore+0x53/0x53 [ 30.279699] panic+0x1e4/0x417 [ 30.282867] ? __warn+0x1d9/0x1d9 [ 30.286291] ? show_regs_print_info+0x65/0x65 [ 30.290771] ? refcount_sub_and_test+0x167/0x1b0 [ 30.295497] __warn+0x1c4/0x1d9 [ 30.298747] ? refcount_sub_and_test+0x167/0x1b0 [ 30.303477] report_bug+0x211/0x2d0 [ 30.307082] fixup_bug+0x40/0x90 [ 30.310430] do_trap+0x260/0x390 [ 30.313775] do_error_trap+0x120/0x390 [ 30.317638] ? do_trap+0x390/0x390 [ 30.321151] ? refcount_sub_and_test+0x167/0x1b0 [ 30.325874] ? vprintk_emit+0x3ea/0x590 [ 30.329828] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 30.334655] do_invalid_op+0x1b/0x20 [ 30.338344] invalid_op+0x18/0x20 [ 30.341768] RIP: 0010:refcount_sub_and_test+0x167/0x1b0 [ 30.347101] RSP: 0018:ffff8801ce746320 EFLAGS: 00010286 [ 30.352438] RAX: 0000000000000026 RBX: 0000000000000001 RCX: 0000000000000000 [ 30.359678] RDX: 0000000000000026 RSI: 1ffff10039ce8c24 RDI: ffffed0039ce8c58 [ 30.366917] RBP: ffff8801ce7463b0 R08: ffff8801ce745a10 R09: 0000000000000000 [ 30.374156] R10: 0000000000000000 R11: 0000000000000000 R12: 1ffff10039ce8c65 [ 30.381394] R13: 00000000ffffff01 R14: 0000000000000100 R15: ffff8801d7d622a4 [ 30.388660] ? refcount_inc+0x50/0x50 [ 30.392434] ? __sctp_outq_teardown+0xc7d/0x15a0 [ 30.397161] ? sctp_association_free+0x2d0/0x930 [ 30.401888] ? sctp_do_sm+0x28e7/0x6dd0 [ 30.405835] ? sctp_primitive_SHUTDOWN+0xa0/0xd0 [ 30.410560] ? sctp_close+0x3c6/0x980 [ 30.414330] ? inet_release+0xed/0x1c0 [ 30.418191] sctp_wfree+0x183/0x620 [ 30.421788] ? __sctp_write_space+0x910/0x910 [ 30.426257] skb_release_head_state+0x124/0x200 [ 30.430905] skb_release_all+0x15/0x60 [ 30.434767] consume_skb+0x153/0x490 [ 30.438449] ? sctp_chunk_put+0x99/0x420 [ 30.442479] ? alloc_skb_with_frags+0x710/0x710 [ 30.447117] ? sctp_chunk_hold+0x20/0x20 [ 30.451150] ? refcount_sub_and_test+0x115/0x1b0 [ 30.455876] ? refcount_inc+0x50/0x50 [ 30.459649] ? mark_held_locks+0xb2/0x100 [ 30.463769] ? sctp_datamsg_put+0x456/0x560 [ 30.468068] sctp_chunk_put+0x29c/0x420 [ 30.472015] ? sctp_chunk_hold+0x20/0x20 [ 30.476048] ? sctp_transport_dst_confirm+0x50/0x50 [ 30.481050] sctp_chunk_free+0x53/0x60 [ 30.484908] __sctp_outq_teardown+0xc7d/0x15a0 [ 30.489459] ? sock_release+0x8d/0x1e0 [ 30.493324] ? sctp_inq_set_th_handler+0x1b0/0x1b0 [ 30.498225] ? unwind_next_frame.part.6+0x1ae/0xc70 [ 30.503219] ? unwind_next_frame.part.6+0x1ae/0xc70 [ 30.508205] ? unwind_dump+0x4c0/0x4c0 [ 30.512076] ? unwind_dump+0x4c0/0x4c0 [ 30.515937] ? copy_trace+0x1d0/0x1d0 [ 30.519714] ? check_noncircular+0x20/0x20 [ 30.523919] ? check_noncircular+0x20/0x20 [ 30.528123] ? unwind_get_return_address+0x61/0xa0 [ 30.533023] ? __save_stack_trace+0x61/0xd0 [ 30.537316] ? check_noncircular+0x20/0x20 [ 30.541524] ? print_usage_bug+0x480/0x480 [ 30.545736] ? find_held_lock+0x39/0x1d0 [ 30.549778] ? lock_downgrade+0x990/0x990 [ 30.553906] ? sk_dst_check+0x560/0x560 [ 30.557853] ? rcu_read_lock_sched_held+0x108/0x120 [ 30.562840] ? lock_release+0xd70/0xd70 [ 30.566790] sctp_outq_free+0x15/0x20 [ 30.570560] sctp_association_free+0x2d0/0x930 [ 30.575115] ? sctp_asconf_queue_teardown+0x700/0x700 [ 30.580273] ? sock_def_wakeup+0x222/0x350 [ 30.584476] ? sk_dst_check+0x560/0x560 [ 30.588419] ? sctp_association_put+0x74/0x2f0 [ 30.592970] ? sctp_association_hold+0x20/0x20 [ 30.597525] ? unwind_get_return_address+0x61/0xa0 [ 30.602424] ? sctp_sm_lookup_event+0x95/0x3c0 [ 30.606979] sctp_do_sm+0x28e7/0x6dd0 [ 30.610762] ? sctp_do_8_2_transport_strike.isra.16+0x8a0/0x8a0 [ 30.616792] ? print_usage_bug+0x480/0x480 [ 30.621000] ? print_usage_bug+0x480/0x480 [ 30.625206] ? find_held_lock+0x39/0x1d0 [ 30.629248] ? lock_downgrade+0x990/0x990 [ 30.633371] ? skb_dequeue+0x22/0x180 [ 30.637150] ? do_raw_spin_trylock+0x190/0x190 [ 30.641707] ? mark_held_locks+0xb2/0x100 [ 30.645833] ? trace_hardirqs_on+0xd/0x10 [ 30.649959] sctp_primitive_SHUTDOWN+0xa0/0xd0 [ 30.654515] sctp_close+0x3c6/0x980 [ 30.658120] ? sctp_apply_peer_addr_params+0xf30/0xf30 [ 30.663365] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 30.668350] ? trace_hardirqs_on+0xd/0x10 [ 30.672475] ? rcu_eqs_enter_common.constprop.73+0x270/0x270 [ 30.678250] ? locks_remove_file+0x3fa/0x5a0 [ 30.682629] ? fcntl_setlk+0x10d0/0x10d0 [ 30.686658] ? lock_downgrade+0x990/0x990 [ 30.690779] ? __fsnotify_parent+0xb4/0x3a0 [ 30.695070] ? ip_mc_drop_socket+0x1ce/0x230 [ 30.699451] inet_release+0xed/0x1c0 [ 30.703139] sock_release+0x8d/0x1e0 [ 30.706823] ? sock_release+0x1e0/0x1e0 [ 30.710772] sock_close+0x16/0x20 [ 30.714195] __fput+0x333/0x7f0 [ 30.717449] ? fput+0x140/0x140 [ 30.720703] ? check_same_owner+0x320/0x320 [ 30.724998] ____fput+0x15/0x20 [ 30.728247] task_work_run+0x199/0x270 [ 30.732107] ? task_work_cancel+0x210/0x210 [ 30.736399] ? free_nsproxy+0x185/0x1f0 [ 30.740341] ? switch_task_namespaces+0xa2/0xc0 [ 30.744986] do_exit+0xa52/0x1b40 [ 30.748413] ? print_usage_bug+0x480/0x480 [ 30.752640] ? mm_update_next_owner+0x930/0x930 [ 30.757281] ? find_held_lock+0x39/0x1d0 [ 30.761317] ? check_noncircular+0x20/0x20 [ 30.765521] ? check_noncircular+0x20/0x20 [ 30.769725] ? lock_downgrade+0x990/0x990 [ 30.773853] ? reacquire_held_locks+0x205/0x3d0 [ 30.778494] ? check_noncircular+0x20/0x20 [ 30.782706] ? find_held_lock+0x39/0x1d0 [ 30.786747] ? lock_downgrade+0x990/0x990 [ 30.790865] ? lock_downgrade+0x990/0x990 [ 30.794985] ? find_held_lock+0x39/0x1d0 [ 30.799025] ? lock_downgrade+0x990/0x990 [ 30.803144] ? recalc_sigpending_tsk+0x117/0x150 [ 30.807871] ? recalc_sigpending+0x103/0x160 [ 30.812248] ? recalc_sigpending_tsk+0x150/0x150 [ 30.816970] ? get_signal+0x397/0x17e0 [ 30.820848] do_group_exit+0x149/0x400 [ 30.824705] ? __lock_is_held+0xbc/0x140 [ 30.828736] ? SyS_exit+0x30/0x30 [ 30.832161] ? _raw_spin_unlock_irq+0x27/0x70 [ 30.836628] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 30.841617] get_signal+0x7e8/0x17e0 [ 30.845330] ? ptrace_notify+0x130/0x130 [ 30.849364] ? __local_bh_enable_ip+0x9d/0x160 [ 30.853928] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 30.858915] ? release_sock+0x1d4/0x2a0 [ 30.862860] ? trace_hardirqs_on+0xd/0x10 [ 30.866977] ? __local_bh_enable_ip+0x9d/0x160 [ 30.871532] ? _raw_spin_unlock_bh+0x30/0x40 [ 30.875908] ? release_sock+0x1d4/0x2a0 [ 30.879853] ? __release_sock+0x360/0x360 [ 30.883971] ? trace_hardirqs_on+0xd/0x10 [ 30.888096] do_signal+0x94/0x1ee0 [ 30.891615] ? inet_sendmsg+0x11f/0x5e0 [ 30.895558] ? inet_sendmsg+0x126/0x5e0 [ 30.899503] ? __might_sleep+0x95/0x190 [ 30.903452] ? setup_sigcontext+0x7d0/0x7d0 [ 30.907745] ? selinux_socket_sendmsg+0x36/0x40 [ 30.912384] ? security_socket_sendmsg+0x89/0xb0 [ 30.917110] ? inet_recvmsg+0x5f0/0x5f0 [ 30.921059] ? sock_sendmsg+0x4f/0x110 [ 30.924918] ? fput+0xd2/0x140 [ 30.928081] ? SYSC_sendto+0x413/0x5a0 [ 30.931942] ? SYSC_connect+0x480/0x480 [ 30.935885] ? __handle_mm_fault+0x39c0/0x39c0 [ 30.940444] ? exit_to_usermode_loop+0x98/0x300 [ 30.945099] exit_to_usermode_loop+0x224/0x300 [ 30.949652] ? trace_event_raw_event_sys_exit+0x260/0x260 [ 30.955165] ? __do_page_fault+0xb60/0xb60 [ 30.959373] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 30.964364] syscall_return_slowpath+0x42f/0x500 [ 30.969088] ? finish_task_switch+0x1aa/0x740 [ 30.973558] ? prepare_exit_to_usermode+0x2c0/0x2c0 [ 30.978549] ? entry_SYSCALL_64_fastpath+0x91/0xbe [ 30.983450] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 30.988437] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 30.993169] entry_SYSCALL_64_fastpath+0xbc/0xbe [ 30.997892] RIP: 0033:0x445dd9 [ 31.001051] RSP: 002b:00007efef3852db8 EFLAGS: 00000212 ORIG_RAX: 000000000000002c [ 31.008731] RAX: 000000000000009b RBX: 0000000000000000 RCX: 0000000000445dd9 [ 31.015970] RDX: 000000000000009b RSI: 0000000020381000 RDI: 0000000000000003 [ 31.023212] RBP: 0000000000000000 R08: 0000000020a63ff0 R09: 0000000000000010 [ 31.030453] R10: 0000000000004000 R11: 0000000000000212 R12: 0000000000000000 [ 31.037699] R13: 00000000007efe8f R14: 00007efef38539c0 R15: 0000000000000000 [ 31.045175] Dumping ftrace buffer: [ 31.048742] (ftrace buffer empty) [ 31.052423] Kernel Offset: disabled [ 31.056027] Rebooting in 86400 seconds..