[....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 19.119868] random: sshd: uninitialized urandom read (32 bytes read) [?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 22.673209] random: sshd: uninitialized urandom read (32 bytes read) [ 23.115966] random: sshd: uninitialized urandom read (32 bytes read) [ 23.994269] random: sshd: uninitialized urandom read (32 bytes read) [ 33.190586] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.10.44' (ECDSA) to the list of known hosts. [ 38.704263] 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 [ 39.530111] ------------[ cut here ]------------ [ 39.535033] refcount_t: underflow; use-after-free. [ 39.540123] WARNING: CPU: 1 PID: 4553 at lib/refcount.c:187 refcount_sub_and_test+0x2e7/0x350 [ 39.548765] Kernel panic - not syncing: panic_on_warn set ... [ 39.548765] [ 39.556114] CPU: 1 PID: 4553 Comm: syz-executor417 Not tainted 4.18.0-rc5+ #150 [ 39.563544] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 39.572879] Call Trace: [ 39.575469] dump_stack+0x1c9/0x2b4 executing program executing program [ 39.579083] ? dump_stack_print_info.cold.2+0x52/0x52 [ 39.584265] panic+0x238/0x4e7 [ 39.587448] ? add_taint.cold.5+0x16/0x16 [ 39.591579] ? __warn.cold.8+0x148/0x1ba [ 39.595634] ? __warn.cold.8+0x117/0x1ba [ 39.599685] ? refcount_sub_and_test+0x2e7/0x350 [ 39.604451] __warn.cold.8+0x163/0x1ba [ 39.608327] ? refcount_sub_and_test+0x2e7/0x350 [ 39.613064] report_bug+0x252/0x2d0 [ 39.616677] do_error_trap+0x1fc/0x4d0 [ 39.620553] ? math_error+0x3e0/0x3e0 [ 39.624343] ? vprintk_default+0x28/0x30 executing program executing program [ 39.628396] ? vprintk_func+0x81/0xe7 [ 39.632190] ? printk+0xa7/0xcf [ 39.635467] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 39.640310] do_invalid_op+0x1b/0x20 [ 39.644011] invalid_op+0x14/0x20 [ 39.647460] RIP: 0010:refcount_sub_and_test+0x2e7/0x350 [ 39.652810] Code: 89 de e8 2c a7 1c fe 84 db 74 07 31 db e9 46 ff ff ff e8 4c a6 1c fe 48 c7 c7 c0 49 1a 88 c6 05 e5 61 3a 06 01 e8 89 c9 e7 fd <0f> 0b 31 db e9 25 ff ff ff 48 8b bd 28 ff ff ff 89 85 34 ff ff ff [ 39.672122] RSP: 0018:ffff8801c36f7780 EFLAGS: 00010286 executing program [ 39.677473] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 [ 39.684724] RDX: 0000000000000000 RSI: ffffffff81631821 RDI: ffff8801c36f7458 [ 39.691975] RBP: ffff8801c36f7868 R08: ffff8801aacd0740 R09: 0000000000000006 [ 39.699236] R10: 0000000000000000 R11: 0000000000000000 R12: 00000000ffffffff [ 39.706500] R13: ffff8801c36f7840 R14: 0000000000000001 R15: 0000000000000000 [ 39.713785] ? vprintk_func+0x81/0xe7 [ 39.717597] ? refcount_inc_not_zero+0x2f0/0x2f0 [ 39.722344] ? graph_lock+0x170/0x170 [ 39.726154] refcount_dec_and_test+0x1a/0x20 executing program executing program [ 39.730544] smap_release_sock+0x76/0x320 [ 39.734686] ? sock_map_alloc+0x410/0x410 [ 39.738825] sock_hash_ctx_update_elem.isra.27+0x8cb/0x1690 [ 39.744535] ? sock_map_free+0x530/0x530 [ 39.748582] ? rcu_is_watching+0x8c/0x150 [ 39.752717] ? rcu_report_qs_rnp+0x7a0/0x7a0 [ 39.757134] ? __fget+0x414/0x670 [ 39.760580] ? expand_files.part.8+0x9c0/0x9c0 [ 39.765149] ? find_held_lock+0x36/0x1c0 [ 39.769211] sock_hash_update_elem+0x157/0x2f0 [ 39.773778] ? bpf_sock_hash_update+0x90/0x90 executing program [ 39.778276] ? kasan_check_read+0x11/0x20 [ 39.782409] ? rcu_is_watching+0x8c/0x150 [ 39.786540] ? rcu_report_qs_rnp+0x7a0/0x7a0 [ 39.790934] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 39.796454] ? bpf_sock_hash_update+0x90/0x90 [ 39.800932] map_update_elem+0x5c4/0xc90 [ 39.804976] __x64_sys_bpf+0x32d/0x510 [ 39.808842] ? bpf_prog_get+0x20/0x20 [ 39.812622] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 39.818142] ? ksys_ioctl+0x81/0xd0 [ 39.821749] ? do_syscall_64+0x9a/0x820 [ 39.825706] do_syscall_64+0x1b9/0x820 executing program [ 39.829585] ? syscall_slow_exit_work+0x500/0x500 [ 39.834420] ? syscall_return_slowpath+0x5e0/0x5e0 [ 39.839334] ? syscall_return_slowpath+0x31d/0x5e0 [ 39.844253] ? entry_SYSCALL_64_after_hwframe+0x59/0xbe [ 39.849608] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 39.854444] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 39.859627] RIP: 0033:0x445929 [ 39.862799] Code: e8 3c b6 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 [ 39.882055] RSP: 002b:00007fdea042edb8 EFLAGS: 00000297 ORIG_RAX: 0000000000000141 [ 39.889749] RAX: ffffffffffffffda RBX: 00000000006dac44 RCX: 0000000000445929 [ 39.897017] RDX: 0000000000000020 RSI: 0000000020000180 RDI: 0000000000000002 [ 39.904274] RBP: 00000000006dac40 R08: 0000000000000000 R09: 0000000000000000 [ 39.911532] R10: 0000000000000000 R11: 0000000000000297 R12: 0000000000000000 [ 39.918782] R13: 00007ffe98ad5fdf R14: 00007fdea042f9c0 R15: 0000000000000009 [ 39.926244] Dumping ftrace buffer: [ 39.929921] (ftrace buffer empty) [ 39.933613] Kernel Offset: disabled [ 39.937234] Rebooting in 86400 seconds..