[....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c.
[....] Starting OpenBSD Secure Shell server: sshd[   16.113220] random: sshd: uninitialized urandom read (32 bytes read)
[?25l[?1c7[ ok 8[?25h[?0c.
[   16.897470] random: sshd: uninitialized urandom read (32 bytes read)
[   17.253928] random: sshd: uninitialized urandom read (32 bytes read)

Debian GNU/Linux 7 syzkaller ttyS0

syzkaller login: [   17.941936] random: sshd: uninitialized urandom read (32 bytes read)
[   18.076336] random: sshd: uninitialized urandom read (32 bytes read)
Warning: Permanently added '10.128.0.13' (ECDSA) to the list of known hosts.
[   23.506872] random: sshd: uninitialized urandom read (32 bytes read)
executing program
[   28.768055] ==================================================================
[   28.775502] BUG: KASAN: use-after-free in _copy_to_user+0xe9/0x110
[   28.781803] Read of size 924 at addr ffff8801a63ffff2 by task syz-executor451/4462
[   28.789497] 
[   28.791111] CPU: 0 PID: 4462 Comm: syz-executor451 Not tainted 4.18.0-rc3+ #48
[   28.798445] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
[   28.807785] Call Trace:
[   28.810365]  dump_stack+0x1c9/0x2b4
[   28.813980]  ? dump_stack_print_info.cold.2+0x52/0x52
[   28.819154]  ? printk+0xa7/0xcf
[   28.822442]  ? kmsg_dump_rewind_nolock+0xe4/0xe4
[   28.827181]  ? _copy_to_user+0xe9/0x110
[   28.831136]  print_address_description+0x6c/0x20b
[   28.835959]  ? _copy_to_user+0xe9/0x110
[   28.839910]  kasan_report.cold.7+0x242/0x2fe
[   28.844310]  check_memory_region+0x13e/0x1b0
[   28.848697]  kasan_check_read+0x11/0x20
[   28.852649]  _copy_to_user+0xe9/0x110
[   28.856436]  bpf_test_finish.isra.7+0xee/0x1f0
[   28.860997]  ? bpf_test_init.isra.8+0x100/0x100
[   28.865650]  ? bpf_test_run+0x2fc/0x3b0
[   28.869605]  bpf_prog_test_run_skb+0x7d7/0xa30
[   28.874166]  ? bpf_test_finish.isra.7+0x1f0/0x1f0
[   28.878990]  ? __sanitizer_cov_trace_const_cmp4+0x16/0x20
[   28.884511]  ? __bpf_prog_get+0x9b/0x290
[   28.888562]  ? bpf_test_finish.isra.7+0x1f0/0x1f0
[   28.893390]  bpf_prog_test_run+0x130/0x1a0
[   28.897608]  __x64_sys_bpf+0x3d8/0x510
[   28.901474]  ? bpf_prog_get+0x20/0x20
[   28.905254]  ? do_page_fault+0xf6/0x8c0
[   28.909209]  do_syscall_64+0x1b9/0x820
[   28.913077]  ? syscall_return_slowpath+0x5e0/0x5e0
[   28.917986]  ? syscall_return_slowpath+0x31d/0x5e0
[   28.922907]  ? prepare_exit_to_usermode+0x3b0/0x3b0
[   28.927903]  ? __sanitizer_cov_trace_const_cmp4+0x16/0x20
[   28.933419]  ? prepare_exit_to_usermode+0x291/0x3b0
[   28.938417]  ? perf_trace_sys_enter+0xb10/0xb10
[   28.943074]  ? trace_hardirqs_off_thunk+0x1a/0x1c
[   28.947898]  entry_SYSCALL_64_after_hwframe+0x49/0xbe
[   28.953065] RIP: 0033:0x4408d9
[   28.956228] Code: e8 4c b2 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 3b 10 fc ff c3 66 2e 0f 1f 84 00 00 00 00 
[   28.975350] RSP: 002b:00007ffe81853788 EFLAGS: 00000213 ORIG_RAX: 0000000000000141
[   28.983038] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00000000004408d9
[   28.990284] RDX: 0000000000000028 RSI: 0000000020000140 RDI: 000000000000000a
[   28.997531] RBP: 0000000000000000 R08: 00000000004002c8 R09: 00000000004002c8
[   29.004788] R10: 000000000251e880 R11: 0000000000000213 R12: 0000000000401da0
[   29.012038] R13: 0000000000401e30 R14: 0000000000000000 R15: 0000000000000000
[   29.019297] 
[   29.020900] The buggy address belongs to the page:
[   29.025810] page:ffffea000698ffc0 count:0 mapcount:0 mapping:0000000000000000 index:0x0
[   29.033929] flags: 0x2fffc0000000000()
[   29.037799] raw: 02fffc0000000000 ffffea000698ffc8 ffffea000698ffc8 0000000000000000
[   29.045667] raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
[   29.053523] page dumped because: kasan: bad access detected
[   29.059206] 
[   29.060808] Memory state around the buggy address:
[   29.065721]  ffff8801a63ffe80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[   29.073061]  ffff8801a63fff00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[   29.080395] >ffff8801a63fff80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[   29.087728]                                                              ^
[   29.094716]  ffff8801a6400000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
[   29.103269]  ffff8801a6400080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
[   29.110605] ==================================================================
[   29.118031] Kernel panic - not syncing: panic_on_warn set ...
[   29.118031] 
[   29.125397] CPU: 0 PID: 4462 Comm: syz-executor451 Tainted: G    B             4.18.0-rc3+ #48
[   29.134127] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
[   29.143459] Call Trace:
[   29.146045]  dump_stack+0x1c9/0x2b4
[   29.149659]  ? dump_stack_print_info.cold.2+0x52/0x52
[   29.154833]  ? trace_hardirqs_on_thunk+0x1a/0x1c
[   29.159573]  panic+0x238/0x4e7
[   29.162745]  ? add_taint.cold.5+0x16/0x16
[   29.166876]  ? do_raw_spin_unlock+0xa7/0x2f0
[   29.171263]  ? do_raw_spin_unlock+0xa7/0x2f0
[   29.175653]  ? _copy_to_user+0xe9/0x110
[   29.179611]  kasan_end_report+0x47/0x4f
[   29.183562]  kasan_report.cold.7+0x76/0x2fe
[   29.187866]  check_memory_region+0x13e/0x1b0
[   29.192257]  kasan_check_read+0x11/0x20
[   29.196211]  _copy_to_user+0xe9/0x110
[   29.199996]  bpf_test_finish.isra.7+0xee/0x1f0
[   29.204563]  ? bpf_test_init.isra.8+0x100/0x100
[   29.209213]  ? bpf_test_run+0x2fc/0x3b0
[   29.213175]  bpf_prog_test_run_skb+0x7d7/0xa30
[   29.217739]  ? bpf_test_finish.isra.7+0x1f0/0x1f0
[   29.222562]  ? __sanitizer_cov_trace_const_cmp4+0x16/0x20
[   29.228079]  ? __bpf_prog_get+0x9b/0x290
[   29.232129]  ? bpf_test_finish.isra.7+0x1f0/0x1f0
[   29.236955]  bpf_prog_test_run+0x130/0x1a0
[   29.241171]  __x64_sys_bpf+0x3d8/0x510
[   29.245040]  ? bpf_prog_get+0x20/0x20
[   29.248821]  ? do_page_fault+0xf6/0x8c0
[   29.252778]  do_syscall_64+0x1b9/0x820
[   29.256657]  ? syscall_return_slowpath+0x5e0/0x5e0
[   29.261567]  ? syscall_return_slowpath+0x31d/0x5e0
[   29.266479]  ? prepare_exit_to_usermode+0x3b0/0x3b0
[   29.271479]  ? __sanitizer_cov_trace_const_cmp4+0x16/0x20
[   29.277003]  ? prepare_exit_to_usermode+0x291/0x3b0
[   29.282009]  ? perf_trace_sys_enter+0xb10/0xb10
[   29.286665]  ? trace_hardirqs_off_thunk+0x1a/0x1c
[   29.291489]  entry_SYSCALL_64_after_hwframe+0x49/0xbe
[   29.296660] RIP: 0033:0x4408d9
[   29.299835] Code: e8 4c b2 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 3b 10 fc ff c3 66 2e 0f 1f 84 00 00 00 00 
[   29.318959] RSP: 002b:00007ffe81853788 EFLAGS: 00000213 ORIG_RAX: 0000000000000141
[   29.326648] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00000000004408d9
[   29.333896] RDX: 0000000000000028 RSI: 0000000020000140 RDI: 000000000000000a
[   29.341143] RBP: 0000000000000000 R08: 00000000004002c8 R09: 00000000004002c8
[   29.348390] R10: 000000000251e880 R11: 0000000000000213 R12: 0000000000401da0
[   29.355635] R13: 0000000000401e30 R14: 0000000000000000 R15: 0000000000000000
[   29.363360] Dumping ftrace buffer:
[   29.366876]    (ftrace buffer empty)
[   29.370559] Kernel Offset: disabled
[   29.374163] Rebooting in 86400 seconds..