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-4,10.128.0.51' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 58.666688] refcount_t: underflow; use-after-free. [ 58.668120] ------------[ cut here ]------------ [ 58.668874] WARNING: CPU: 1 PID: 3009 at lib/refcount.c:186 refcount_sub_and_test+0x167/0x1b0 [ 58.670284] Kernel panic - not syncing: panic_on_warn set ... [ 58.670284] [ 58.671412] CPU: 1 PID: 3009 Comm: syzkaller633078 Not tainted 4.13.0-rc5+ #43 [ 58.672462] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 58.673849] Call Trace: [ 58.674207] dump_stack+0x194/0x257 [ 58.674702] ? arch_local_irq_restore+0x53/0x53 [ 58.675333] panic+0x1e4/0x417 [ 58.675766] ? __warn+0x1d9/0x1d9 [ 58.676230] ? show_regs_print_info+0x65/0x65 [ 58.676885] ? retint_kernel+0x10/0x10 [ 58.677497] ? refcount_sub_and_test+0x167/0x1b0 [ 58.678174] __warn+0x1c4/0x1d9 [ 58.678653] ? refcount_sub_and_test+0x169/0x1b0 [ 58.679285] ? refcount_sub_and_test+0x167/0x1b0 [ 58.679970] report_bug+0x211/0x2d0 [ 58.680545] fixup_bug+0x40/0x90 [ 58.681001] do_trap+0x260/0x390 [ 58.681499] do_error_trap+0x120/0x390 [ 58.682080] ? vprintk_emit+0x49b/0x590 [ 58.682615] ? do_trap+0x390/0x390 [ 58.683138] ? refcount_sub_and_test+0x167/0x1b0 [ 58.683790] ? vprintk_emit+0x3ea/0x590 [ 58.684350] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 58.685116] do_invalid_op+0x1b/0x20 [ 58.685614] invalid_op+0x1e/0x30 [ 58.686077] RIP: 0010:refcount_sub_and_test+0x167/0x1b0 [ 58.686806] RSP: 0018:ffff8801d06dece8 EFLAGS: 00010286 [ 58.691335] RAX: 0000000000000026 RBX: 0000000000000001 RCX: 0000000000000000 [ 58.698573] RDX: 0000000000000026 RSI: 1ffff1003a0dbd5d RDI: ffffed003a0dbd91 [ 58.705808] RBP: ffff8801d06ded78 R08: 0000000000000001 R09: 0000000000000000 [ 58.713061] R10: 0000000000000000 R11: 0000000000000000 R12: 1ffff1003a0dbd9e [ 58.720313] R13: 00000000ffffff01 R14: 0000000000000100 R15: ffff8801cf1bd9fc [ 58.727584] ? refcount_sub_and_test+0x167/0x1b0 [ 58.732307] ? refcount_inc+0x50/0x50 [ 58.736083] ? __sctp_outq_teardown+0xc7d/0x15a0 [ 58.740808] ? sctp_association_free+0x2d0/0x930 [ 58.745539] ? sctp_do_sm+0x28e7/0x6d90 [ 58.749484] ? sctp_primitive_SHUTDOWN+0xa0/0xd0 [ 58.754209] ? sctp_close+0x3c6/0x980 [ 58.757978] ? inet_release+0xed/0x1c0 [ 58.761836] sctp_wfree+0x183/0x620 [ 58.765430] ? __sctp_write_space+0x910/0x910 [ 58.769897] skb_release_head_state+0x124/0x200 [ 58.774535] skb_release_all+0x15/0x60 [ 58.778404] consume_skb+0x153/0x490 [ 58.782114] ? sctp_chunk_put+0x99/0x420 [ 58.786145] ? pskb_carve+0x1db0/0x1db0 [ 58.790088] ? sctp_chunk_hold+0x20/0x20 [ 58.794119] ? refcount_sub_and_test+0x115/0x1b0 [ 58.798847] ? refcount_inc+0x50/0x50 [ 58.802613] ? mark_held_locks+0xaf/0x100 [ 58.806730] ? sctp_datamsg_put+0x456/0x560 [ 58.811026] sctp_chunk_put+0x29c/0x420 [ 58.814978] ? sctp_chunk_hold+0x20/0x20 [ 58.819020] ? sctp_transport_dst_confirm+0x50/0x50 [ 58.824021] ? check_noncircular+0x20/0x20 [ 58.828220] ? check_noncircular+0x20/0x20 [ 58.832444] sctp_chunk_free+0x53/0x60 [ 58.836300] __sctp_outq_teardown+0xc7d/0x15a0 [ 58.840858] ? sctp_inq_set_th_handler+0x1b0/0x1b0 [ 58.845757] ? try_to_wake_up+0xf9/0x1600 [ 58.849871] ? lock_downgrade+0x990/0x990 [ 58.853983] ? lock_downgrade+0x990/0x990 [ 58.858112] ? do_raw_spin_trylock+0x190/0x190 [ 58.862658] ? do_raw_spin_trylock+0x190/0x190 [ 58.867223] ? trace_hardirqs_off+0xd/0x10 [ 58.871425] ? _raw_spin_unlock_irqrestore+0xa6/0xba [ 58.876496] ? try_to_wake_up+0xf9/0x1600 [ 58.880621] ? check_noncircular+0x20/0x20 [ 58.884826] ? migrate_swap_stop+0x970/0x970 [ 58.889203] ? save_stack_trace+0x16/0x20 [ 58.893319] ? save_trace+0x11f/0x350 [ 58.897092] ? print_usage_bug+0x480/0x480 [ 58.901291] ? lock_acquire+0x1d5/0x580 [ 58.905253] ? lock_acquire+0x1d5/0x580 [ 58.909196] ? lock_timer_base+0x1a3/0x2b0 [ 58.913401] ? find_held_lock+0x35/0x1d0 [ 58.917438] ? sock_def_wakeup+0x1f9/0x350 [ 58.921661] ? lock_downgrade+0x990/0x990 [ 58.925774] ? find_held_lock+0x35/0x1d0 [ 58.929804] ? lock_release+0xa40/0xa40 [ 58.933751] sctp_outq_free+0x15/0x20 [ 58.937519] sctp_association_free+0x2d0/0x930 [ 58.942076] ? sctp_asconf_queue_teardown+0x700/0x700 [ 58.947236] ? sock_def_wakeup+0x222/0x350 [ 58.951448] ? sk_dst_check+0x560/0x560 [ 58.955392] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 58.960376] ? trace_hardirqs_on+0xd/0x10 [ 58.964493] ? __wake_up+0x3f/0x50 [ 58.968243] sctp_do_sm+0x28e7/0x6d90 [ 58.972011] ? debug_check_no_locks_freed+0x3c0/0x3c0 [ 58.977186] ? sctp_do_8_2_transport_strike.isra.16+0x8a0/0x8a0 [ 58.983213] ? debug_check_no_locks_freed+0x3c0/0x3c0 [ 58.988371] ? print_usage_bug+0x480/0x480 [ 58.992576] ? print_usage_bug+0x480/0x480 [ 58.996787] ? reacquire_held_locks+0x1fd/0x3d0 [ 59.001432] ? find_held_lock+0x35/0x1d0 [ 59.005469] ? skb_dequeue+0x12a/0x180 [ 59.009324] ? lock_downgrade+0x990/0x990 [ 59.013443] ? do_raw_spin_trylock+0x190/0x190 [ 59.018003] ? mark_held_locks+0xaf/0x100 [ 59.022124] ? trace_hardirqs_on+0xd/0x10 [ 59.026245] sctp_primitive_SHUTDOWN+0xa0/0xd0 [ 59.030796] sctp_close+0x3c6/0x980 [ 59.034406] ? sctp_apply_peer_addr_params+0xf30/0xf30 [ 59.039654] ? check_noncircular+0x20/0x20 [ 59.043853] ? lock_downgrade+0x990/0x990 [ 59.047966] ? lock_downgrade+0x990/0x990 [ 59.052093] ? do_raw_spin_trylock+0x190/0x190 [ 59.056653] ? locks_remove_file+0x414/0x560 [ 59.061037] ? fcntl_setlk+0x10c0/0x10c0 [ 59.065069] ? __fsnotify_parent+0xb4/0x3a0 [ 59.069356] ? ip_mc_drop_socket+0x1ce/0x230 [ 59.073736] inet_release+0xed/0x1c0 [ 59.077420] sock_release+0x8d/0x1e0 [ 59.081109] ? sock_release+0x1e0/0x1e0 [ 59.085052] sock_close+0x16/0x20 [ 59.088474] __fput+0x327/0x7e0 [ 59.091725] ? fput+0x140/0x140 [ 59.094972] ? alloc_fdtable+0x280/0x280 [ 59.099007] ? cpumask_weight.constprop.3+0x45/0x45 [ 59.103997] ____fput+0x15/0x20 [ 59.107252] task_work_run+0x18a/0x260 [ 59.111148] ? task_work_cancel+0x210/0x210 [ 59.115445] ? exit_to_usermode_loop+0x98/0x300 [ 59.120100] exit_to_usermode_loop+0x2a6/0x300 [ 59.124653] ? trace_event_raw_event_sys_exit+0x260/0x260 [ 59.130165] ? handle_mm_fault+0x4a2/0x860 [ 59.134388] syscall_return_slowpath+0x3a7/0x450 [ 59.139125] ? prepare_exit_to_usermode+0x220/0x220 [ 59.144109] ? entry_SYSCALL_64_fastpath+0x91/0xbe [ 59.149005] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 59.153988] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 59.158718] entry_SYSCALL_64_fastpath+0xbc/0xbe [ 59.163438] RIP: 0033:0x445d39 [ 59.166595] RSP: 002b:00007f25c5962dc8 EFLAGS: 00000202 ORIG_RAX: 000000000000002b [ 59.174268] RAX: ffffffffffffff99 RBX: 0000000000000000 RCX: 0000000000445d39 [ 59.181506] RDX: 0000000020ffd000 RSI: 0000000020ffc000 RDI: 0000000000000003 [ 59.188743] RBP: 0000000000000000 R08: 00007f25c5963700 R09: 00007f25c5963700 [ 59.195988] R10: 00007f25c5963700 R11: 0000000000000202 R12: 0000000000000000 [ 59.203225] R13: 00007ffe3dee4cbf R14: 00007f25c59639c0 R15: 0000000000000000 [ 59.210962] Dumping ftrace buffer: [ 59.214513] (ftrace buffer empty) [ 59.218197] Kernel Offset: disabled [ 59.221792] Rebooting in 86400 seconds..