[....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 16.166800] random: sshd: uninitialized urandom read (32 bytes read) [?25l[?1c7[ ok 8[?25h[?0c. [ 17.207933] random: sshd: uninitialized urandom read (32 bytes read) Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 17.549826] random: sshd: uninitialized urandom read (32 bytes read) [ 18.300342] random: sshd: uninitialized urandom read (32 bytes read) [ 64.310846] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.0.9' (ECDSA) to the list of known hosts. [ 69.824959] random: sshd: uninitialized urandom read (32 bytes read) executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 70.767203] ------------[ cut here ]------------ [ 70.772040] refcount_t: underflow; use-after-free. [ 70.777243] WARNING: CPU: 1 PID: 4458 at lib/refcount.c:187 refcount_sub_and_test+0x2e7/0x350 [ 70.785891] Kernel panic - not syncing: panic_on_warn set ... [ 70.785891] [ 70.793362] CPU: 1 PID: 4458 Comm: syz-executor325 Not tainted 4.18.0-rc3+ #55 [ 70.800717] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 70.810058] Call Trace: [ 70.812640] dump_stack+0x1c9/0x2b4 executing program executing program [ 70.816261] ? dump_stack_print_info.cold.2+0x52/0x52 [ 70.821450] panic+0x238/0x4e7 [ 70.824627] ? add_taint.cold.5+0x16/0x16 [ 70.828785] ? __warn.cold.8+0x148/0x1ba [ 70.832839] ? __warn.cold.8+0x117/0x1ba [ 70.836925] ? refcount_sub_and_test+0x2e7/0x350 [ 70.841700] __warn.cold.8+0x163/0x1ba [ 70.845592] ? refcount_sub_and_test+0x2e7/0x350 [ 70.850342] report_bug+0x252/0x2d0 [ 70.853957] do_error_trap+0x1fc/0x4d0 [ 70.857835] ? math_error+0x3e0/0x3e0 [ 70.861631] ? vprintk_default+0x28/0x30 executing program executing program [ 70.865678] ? vprintk_func+0x81/0xe7 [ 70.869462] ? printk+0xa7/0xcf [ 70.872739] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 70.877578] do_invalid_op+0x1b/0x20 [ 70.881276] invalid_op+0x14/0x20 [ 70.884716] RIP: 0010:refcount_sub_and_test+0x2e7/0x350 [ 70.890060] Code: 89 de e8 ec c0 1c fe 84 db 74 07 31 db e9 46 ff ff ff e8 0c c0 1c fe 48 c7 c7 20 42 1a 88 c6 05 0d 83 3a 06 01 e8 d9 e2 e7 fd <0f> 0b 31 db e9 25 ff ff ff 48 8b bd 28 ff ff ff 89 85 34 ff ff ff [ 70.909834] RSP: 0018:ffff8801d915f780 EFLAGS: 00010286 executing program [ 70.915183] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 [ 70.922438] RDX: 0000000000000000 RSI: ffffffff81631851 RDI: ffff8801d915f458 [ 70.929692] RBP: ffff8801d915f868 R08: ffff8801ac6bc440 R09: fffffbfff11f1220 [ 70.936948] R10: fffffbfff11f1220 R11: ffffffff88f89103 R12: 00000000ffffffff [ 70.944551] R13: ffff8801d915f840 R14: 0000000000000001 R15: 0000000000000000 [ 70.951842] ? vprintk_func+0x81/0xe7 [ 70.955641] ? refcount_inc_not_zero+0x2f0/0x2f0 [ 70.960386] ? trace_hardirqs_off+0xd/0x10 executing program executing program [ 70.964604] ? _raw_spin_unlock_irqrestore+0x63/0xc0 [ 70.969697] refcount_dec_and_test+0x1a/0x20 [ 70.974107] smap_release_sock+0x76/0x320 [ 70.978587] ? sock_map_alloc+0x410/0x410 [ 70.982726] ? __kasan_slab_free+0x131/0x170 [ 70.987129] ? trace_hardirqs_on+0xd/0x10 [ 70.991273] sock_hash_ctx_update_elem.isra.27+0x8cb/0x1690 [ 70.996985] ? sock_map_free+0x530/0x530 [ 71.001037] ? perf_trace_lock_acquire+0xeb/0x9a0 [ 71.005866] ? __fget+0x414/0x670 [ 71.009307] ? expand_files.part.8+0x9c0/0x9c0 [ 71.013890] ? lock_acquire+0x1e4/0x540 executing program [ 71.017851] ? lock_acquire+0x1e4/0x540 [ 71.021816] sock_hash_update_elem+0x157/0x2f0 [ 71.026393] ? bpf_sock_hash_update+0x90/0x90 [ 71.030887] ? lock_release+0xa30/0xa30 [ 71.034850] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 71.040386] ? bpf_sock_hash_update+0x90/0x90 [ 71.044876] map_update_elem+0x5c4/0xc90 [ 71.049014] __x64_sys_bpf+0x32d/0x510 [ 71.052886] ? bpf_prog_get+0x20/0x20 [ 71.056675] ? do_syscall_64+0x16b/0x820 [ 71.060722] do_syscall_64+0x1b9/0x820 executing program [ 71.064596] ? finish_task_switch+0x1d3/0x890 [ 71.069070] ? syscall_return_slowpath+0x5e0/0x5e0 [ 71.073985] ? syscall_return_slowpath+0x31d/0x5e0 [ 71.078923] ? prepare_exit_to_usermode+0x3b0/0x3b0 [ 71.083942] ? prepare_exit_to_usermode+0x291/0x3b0 [ 71.088940] ? perf_trace_sys_enter+0xb10/0xb10 [ 71.093594] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 71.099481] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 71.104673] RIP: 0033:0x446eb9 executing program [ 71.107853] Code: e8 2c b7 02 00 48 83 c4 18 c3 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 2b 12 fc ff c3 66 2e 0f 1f 84 00 00 00 00 [ 71.127023] RSP: 002b:00007fa2f3c96ce8 EFLAGS: 00000246 ORIG_RAX: 0000000000000141 [ 71.134713] RAX: ffffffffffffffda RBX: 00000000006dbc44 RCX: 0000000000446eb9 [ 71.141975] RDX: 0000000000000020 RSI: 0000000020000180 RDI: 0000000000000002 [ 71.149238] RBP: 00000000006dbc40 R08: 0000000000000000 R09: 0000000000000000 [ 71.156506] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 [ 71.163763] R13: 00007ffe4c9eb99f R14: 00007fa2f3c979c0 R15: 0000000000000009 [ 71.171522] Dumping ftrace buffer: [ 71.175043] (ftrace buffer empty) [ 71.178734] Kernel Offset: disabled [ 71.182346] Rebooting in 86400 seconds..