[ OK ] Listening on Load/Save RF Kill Switch Status /dev/rfkill Watch. [ OK ] Started Serial Getty on ttyS0. [ OK ] Reached target Login Prompts. [ OK ] Reached target Multi-User System. [ OK ] Reached target Graphical Interface. Starting Update UTMP about System Runlevel Changes... Debian GNU/Linux 9 syzkaller ttyS0 Warning: Permanently added '10.128.1.61' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 66.023661][ T7215] ------------[ cut here ]------------ [ 66.029701][ T7215] refcount_t: underflow; use-after-free. [ 66.036079][ T7215] WARNING: CPU: 0 PID: 7215 at lib/refcount.c:28 refcount_warn_saturate+0x1d1/0x1e0 [ 66.045537][ T7215] Kernel panic - not syncing: panic_on_warn set ... [ 66.052206][ T7215] CPU: 0 PID: 7215 Comm: syz-executor053 Not tainted 5.6.0-rc7-syzkaller #0 [ 66.060863][ T7215] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 66.072225][ T7215] Call Trace: [ 66.075515][ T7215] dump_stack+0x188/0x20d [ 66.080016][ T7215] ? refcount_warn_saturate+0x190/0x1e0 [ 66.086182][ T7215] panic+0x2e3/0x75c [ 66.090099][ T7215] ? add_taint.cold+0x16/0x16 [ 66.094809][ T7215] ? __probe_kernel_read+0x188/0x1d0 [ 66.100094][ T7215] ? __warn.cold+0x14/0x35 [ 66.104974][ T7215] ? __warn+0xd5/0x1c8 [ 66.109058][ T7215] ? refcount_warn_saturate+0x1d1/0x1e0 [ 66.114687][ T7215] __warn.cold+0x2f/0x35 [ 66.118956][ T7215] ? refcount_warn_saturate+0x1d1/0x1e0 [ 66.124496][ T7215] report_bug+0x27b/0x2f0 [ 66.128988][ T7215] do_error_trap+0x12b/0x220 [ 66.133565][ T7215] ? refcount_warn_saturate+0x1d1/0x1e0 [ 66.139095][ T7215] do_invalid_op+0x32/0x40 [ 66.143491][ T7215] ? refcount_warn_saturate+0x1d1/0x1e0 [ 66.150124][ T7215] invalid_op+0x23/0x30 [ 66.154281][ T7215] RIP: 0010:refcount_warn_saturate+0x1d1/0x1e0 [ 66.160421][ T7215] Code: e9 db fe ff ff 48 89 df e8 4c 63 1f fe e9 8a fe ff ff e8 f2 99 e2 fd 48 c7 c7 00 a9 51 88 c6 05 c6 a0 d1 06 01 e8 d7 aa b4 fd <0f> 0b e9 af fe ff ff 0f 1f 84 00 00 00 00 00 41 56 41 55 41 54 55 [ 66.180005][ T7215] RSP: 0018:ffffc90001607698 EFLAGS: 00010286 [ 66.186062][ T7215] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 [ 66.194020][ T7215] RDX: 0000000000000000 RSI: ffffffff815c06c1 RDI: fffff520002c0ec5 [ 66.201987][ T7215] RBP: 0000000000000003 R08: ffff888089d20140 R09: ffffed1015cc6659 [ 66.209955][ T7215] R10: ffffed1015cc6658 R11: ffff8880ae6332c7 R12: 0000000000008100 [ 66.217939][ T7215] R13: ffff8880a715ba04 R14: ffff88808fec3540 R15: ffff88808fec3580 [ 66.225919][ T7215] ? vprintk_func+0x81/0x17e [ 66.230498][ T7215] ? refcount_warn_saturate+0x1d1/0x1e0 [ 66.236027][ T7215] sock_wfree+0x1e3/0x240 [ 66.240338][ T7215] sctp_wfree+0x372/0x960 [ 66.246048][ T7215] ? rcu_read_lock_sched_held+0x9c/0xd0 [ 66.252067][ T7215] ? __sctp_write_space+0x5c0/0x5c0 [ 66.257296][ T7215] skb_release_head_state+0xe2/0x250 [ 66.262828][ T7215] skb_release_all+0x11/0x60 [ 66.267398][ T7215] consume_skb+0xf3/0x400 [ 66.271713][ T7215] sctp_chunk_put+0x1c0/0x2d0 [ 66.276558][ T7215] __sctp_outq_teardown+0x715/0xc60 [ 66.281772][ T7215] sctp_association_free+0x212/0x7e0 [ 66.287100][ T7215] sctp_do_sm+0x3911/0x4ed0 [ 66.293003][ T7215] ? rcu_read_lock_any_held.part.0+0x50/0x50 [ 66.299066][ T7215] ? sctp_do_8_2_transport_strike.isra.0+0xa60/0xa60 [ 66.305749][ T7215] ? kmem_cache_alloc_node_trace+0x3a2/0x790 [ 66.311999][ T7215] ? sctp_chunkify+0x46/0x290 [ 66.316693][ T7215] ? rcu_read_lock_sched_held+0x9c/0xd0 [ 66.322234][ T7215] ? rcu_read_lock_any_held.part.0+0x50/0x50 [ 66.329844][ T7215] ? __kasan_kmalloc.constprop.0+0xbf/0xd0 [ 66.335636][ T7215] ? kmem_cache_alloc+0x261/0x730 [ 66.340660][ T7215] ? sctp_addto_chunk+0x290/0x290 [ 66.345664][ T7215] ? skb_put+0x15d/0x1c0 [ 66.350261][ T7215] ? memcpy+0x35/0x50 [ 66.354240][ T7215] sctp_primitive_ABORT+0x9b/0xc0 [ 66.359254][ T7215] sctp_close+0x22e/0x8a0 [ 66.363658][ T7215] ? sctp_accept+0x6a0/0x6a0 [ 66.368233][ T7215] ? down_write+0xdb/0x150 [ 66.372726][ T7215] ? ip_mc_drop_socket+0x16/0x260 [ 66.377834][ T7215] ? __sock_release+0x280/0x280 [ 66.382688][ T7215] inet_release+0xe4/0x1f0 [ 66.387099][ T7215] __sock_release+0xcd/0x280 [ 66.391848][ T7215] sock_close+0x18/0x20 [ 66.395993][ T7215] __fput+0x2da/0x850 [ 66.399966][ T7215] task_work_run+0x13f/0x1b0 [ 66.404543][ T7215] do_exit+0xb34/0x2dd0 [ 66.410792][ T7215] ? mm_update_next_owner+0x7a0/0x7a0 [ 66.416175][ T7215] ? __sys_getsockopt+0x18d/0x2e0 [ 66.421197][ T7215] ? kernel_accept+0x360/0x360 [ 66.425967][ T7215] ? down_read_non_owner+0x470/0x470 [ 66.431241][ T7215] ? handle_mm_fault+0x491/0xa10 [ 66.437571][ T7215] do_group_exit+0x125/0x340 [ 66.442162][ T7215] __x64_sys_exit_group+0x3a/0x50 [ 66.447167][ T7215] do_syscall_64+0xf6/0x7d0 [ 66.451769][ T7215] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 66.457642][ T7215] RIP: 0033:0x43ef98 [ 66.461534][ T7215] Code: Bad RIP value. [ 66.465578][ T7215] RSP: 002b:00007ffc04c40db8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 66.474190][ T7215] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000043ef98 [ 66.482247][ T7215] RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000 [ 66.490640][ T7215] RBP: 00000000004be7a8 R08: 00000000000000e7 R09: ffffffffffffffd0 [ 66.498640][ T7215] R10: 000000002059aff8 R11: 0000000000000246 R12: 0000000000000001 [ 66.506680][ T7215] R13: 00000000006d01a0 R14: 0000000000000000 R15: 0000000000000000 [ 66.516261][ T7215] Kernel Offset: disabled [ 66.520772][ T7215] Rebooting in 86400 seconds..