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-kasan-gce-1,10.128.0.53' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 53.734906] refcount_t: underflow; use-after-free. [ 53.735767] ------------[ cut here ]------------ [ 53.736544] WARNING: CPU: 0 PID: 3006 at lib/refcount.c:186 refcount_sub_and_test+0x167/0x1b0 [ 53.737701] Kernel panic - not syncing: panic_on_warn set ... [ 53.737701] [ 53.738739] CPU: 0 PID: 3006 Comm: syzkaller031791 Not tainted 4.13.0-rc6+ #52 [ 53.739703] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 53.740925] Call Trace: [ 53.741283] dump_stack+0x194/0x257 [ 53.741774] ? arch_local_irq_restore+0x53/0x53 [ 53.742405] panic+0x1e4/0x417 [ 53.742837] ? __warn+0x1d9/0x1d9 [ 53.743302] ? show_regs_print_info+0x65/0x65 [ 53.743911] ? refcount_sub_and_test+0x167/0x1b0 [ 53.744543] __warn+0x1c4/0x1d9 [ 53.745005] ? refcount_sub_and_test+0x167/0x1b0 [ 53.745641] report_bug+0x211/0x2d0 [ 53.746133] fixup_bug+0x40/0x90 [ 53.746587] do_trap+0x260/0x390 [ 53.747048] do_error_trap+0x120/0x390 [ 53.747568] ? vprintk_emit+0x49b/0x590 [ 53.748103] ? do_trap+0x390/0x390 [ 53.748580] ? refcount_sub_and_test+0x167/0x1b0 [ 53.749212] ? vprintk_emit+0x3ea/0x590 [ 53.749752] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 53.750400] do_invalid_op+0x1b/0x20 [ 53.750916] invalid_op+0x1e/0x30 [ 53.751380] RIP: 0010:refcount_sub_and_test+0x167/0x1b0 [ 53.752101] RSP: 0018:ffff8801d0c86928 EFLAGS: 00010282 [ 53.752810] RAX: 0000000000000026 RBX: 0000000000000001 RCX: 0000000000000000 [ 53.753761] RDX: 0000000000000026 RSI: 1ffff1003a190ce5 RDI: ffffed003a190d19 [ 53.754713] RBP: ffff8801d0c869b8 R08: 0000000000000001 R09: 0000000000000000 [ 53.755664] R10: 0000000000000000 R11: 0000000000000000 R12: 1ffff1003a190d26 [ 53.762901] R13: 00000000ffffff01 R14: 0000000000000100 R15: ffff8801cf38aa3c [ 53.770170] ? refcount_sub_and_test+0x167/0x1b0 [ 53.774893] ? refcount_inc+0x50/0x50 [ 53.778661] ? __sctp_outq_teardown+0xc7d/0x15a0 [ 53.783384] ? sctp_association_free+0x2d0/0x930 [ 53.788103] ? sctp_do_sm+0x28e7/0x6d90 [ 53.792044] ? sctp_primitive_SHUTDOWN+0xa0/0xd0 [ 53.796764] ? sctp_close+0x3c6/0x980 [ 53.800530] ? inet_release+0xed/0x1c0 [ 53.804388] sctp_wfree+0x183/0x620 [ 53.807980] ? __sctp_write_space+0x910/0x910 [ 53.812446] skb_release_head_state+0x124/0x200 [ 53.817090] skb_release_all+0x15/0x60 [ 53.820943] consume_skb+0x153/0x490 [ 53.824624] ? sctp_chunk_put+0x99/0x420 [ 53.828652] ? pskb_carve+0x1db0/0x1db0 [ 53.832594] ? sctp_chunk_hold+0x20/0x20 [ 53.836632] ? refcount_sub_and_test+0x115/0x1b0 [ 53.841355] ? refcount_inc+0x50/0x50 [ 53.845121] ? mark_held_locks+0xaf/0x100 [ 53.849238] ? sctp_datamsg_put+0x456/0x560 [ 53.853535] sctp_chunk_put+0x29c/0x420 [ 53.857478] ? sctp_chunk_hold+0x20/0x20 [ 53.861515] ? sctp_transport_dst_confirm+0x50/0x50 [ 53.866524] sctp_chunk_free+0x53/0x60 [ 53.870382] __sctp_outq_teardown+0xc7d/0x15a0 [ 53.874946] ? bpf_prog_kallsyms_find+0xbd/0x440 [ 53.879675] ? sctp_inq_set_th_handler+0x1b0/0x1b0 [ 53.884567] ? is_bpf_text_address+0x7b/0x120 [ 53.889031] ? lock_downgrade+0x990/0x990 [ 53.893150] ? lock_release+0xa40/0xa40 [ 53.897095] ? update_stack_state+0x700/0x700 [ 53.901557] ? print_usage_bug+0x480/0x480 [ 53.905773] ? is_bpf_text_address+0xa4/0x120 [ 53.910237] ? __kernel_text_address+0xae/0xe0 [ 53.914787] ? unwind_get_return_address+0x61/0xa0 [ 53.919684] ? __save_stack_trace+0x7e/0xd0 [ 53.923978] ? check_noncircular+0x20/0x20 [ 53.928186] ? print_usage_bug+0x480/0x480 [ 53.932401] ? save_stack_trace+0x16/0x20 [ 53.936522] ? save_trace+0x11f/0x350 [ 53.940304] ? lock_acquire+0x1d5/0x580 [ 53.944256] ? lock_acquire+0x1d5/0x580 [ 53.948205] ? lock_timer_base+0x1a3/0x2b0 [ 53.952419] ? find_held_lock+0x35/0x1d0 [ 53.956465] ? sock_def_wakeup+0x1f9/0x350 [ 53.960673] ? lock_downgrade+0x990/0x990 [ 53.964798] ? lock_release+0xa40/0xa40 [ 53.968768] sctp_outq_free+0x15/0x20 [ 53.972542] sctp_association_free+0x2d0/0x930 [ 53.977105] ? sctp_asconf_queue_teardown+0x700/0x700 [ 53.982275] ? sock_def_wakeup+0x222/0x350 [ 53.986479] ? sk_dst_check+0x560/0x560 [ 53.990424] ? sctp_association_put+0x74/0x2f0 [ 53.994977] ? sctp_association_hold+0x20/0x20 [ 53.999540] ? sctp_sm_lookup_event+0x95/0x3c0 [ 54.004093] sctp_do_sm+0x28e7/0x6d90 [ 54.007864] ? check_noncircular+0x20/0x20 [ 54.012077] ? sctp_do_8_2_transport_strike.isra.16+0x8a0/0x8a0 [ 54.018115] ? print_usage_bug+0x480/0x480 [ 54.022333] ? print_usage_bug+0x480/0x480 [ 54.026569] ? find_held_lock+0x35/0x1d0 [ 54.030610] ? skb_dequeue+0x12a/0x180 [ 54.034465] ? lock_downgrade+0x990/0x990 [ 54.038584] ? do_raw_spin_trylock+0x190/0x190 [ 54.043136] ? mark_held_locks+0xaf/0x100 [ 54.047256] ? trace_hardirqs_on+0xd/0x10 [ 54.051379] sctp_primitive_SHUTDOWN+0xa0/0xd0 [ 54.055933] sctp_close+0x3c6/0x980 [ 54.059533] ? sctp_apply_peer_addr_params+0xf30/0xf30 [ 54.064777] ? unwind_get_return_address+0x61/0xa0 [ 54.069679] ? __save_stack_trace+0x7e/0xd0 [ 54.073974] ? check_noncircular+0x20/0x20 [ 54.078182] ? ipv6_sock_ac_close+0x2e8/0x3e0 [ 54.082649] ? ipv6_sock_mc_close+0x148/0x1a0 [ 54.087117] ? ipv6_sock_ac_drop+0x580/0x580 [ 54.091494] ? ip_mc_drop_socket+0x1ce/0x230 [ 54.095867] ? __fsnotify_parent+0xb4/0x3a0 [ 54.100159] inet_release+0xed/0x1c0 [ 54.103841] inet6_release+0x50/0x70 [ 54.107520] sock_release+0x8d/0x1e0 [ 54.111199] ? sock_release+0x1e0/0x1e0 [ 54.115137] sock_close+0x16/0x20 [ 54.118566] __fput+0x327/0x7e0 [ 54.121816] ? fput+0x140/0x140 [ 54.125061] ? do_raw_spin_trylock+0x190/0x190 [ 54.129612] ? check_same_owner+0x320/0x320 [ 54.133916] ____fput+0x15/0x20 [ 54.137166] task_work_run+0x18a/0x260 [ 54.141021] ? task_work_cancel+0x210/0x210 [ 54.145312] ? _raw_spin_unlock+0x22/0x30 [ 54.149425] ? switch_task_namespaces+0x87/0xc0 [ 54.154110] do_exit+0xa3a/0x1b10 [ 54.157527] ? find_held_lock+0x35/0x1d0 [ 54.161563] ? lock_downgrade+0x990/0x990 [ 54.165677] ? mm_update_next_owner+0x930/0x930 [ 54.170314] ? __lock_is_held+0xb6/0x140 [ 54.174356] ? __fd_install+0x2f7/0x6a0 [ 54.178296] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 54.183023] ? get_unused_fd_flags+0x190/0x190 [ 54.187583] ? copy_user_generic_unrolled+0x89/0xc0 [ 54.192568] ? _copy_to_user+0xa2/0xc0 [ 54.196425] ? fd_install+0x4d/0x60 [ 54.200018] ? SYSC_accept4+0x4ec/0x850 [ 54.203962] ? kernel_accept+0x2f0/0x2f0 [ 54.207988] ? lock_downgrade+0x990/0x990 [ 54.212119] ? handle_mm_fault+0x4a2/0x860 [ 54.216323] ? __handle_mm_fault+0x3860/0x3860 [ 54.220868] ? vmacache_find+0x61/0x270 [ 54.224816] do_group_exit+0x149/0x400 [ 54.228673] ? SyS_exit+0x30/0x30 [ 54.232102] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 54.237090] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 54.241819] SyS_exit_group+0x1d/0x20 [ 54.245588] entry_SYSCALL_64_fastpath+0x1f/0xbe [ 54.250307] RIP: 0033:0x43ea08 [ 54.253462] RSP: 002b:00007ffc57dc2da8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 54.261137] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000043ea08 [ 54.268374] RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000 [ 54.275611] RBP: 0000000000000086 R08: 00000000000000e7 R09: ffffffffffffffd0 [ 54.282849] R10: 000000000000001c R11: 0000000000000246 R12: 0000000000401730 [ 54.290088] R13: 00000000004017c0 R14: 0000000000000000 R15: 0000000000000000 [ 54.297799] Dumping ftrace buffer: [ 54.301366] (ftrace buffer empty) [ 54.305057] Kernel Offset: disabled [ 54.308654] Rebooting in 86400 seconds..