[....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c.
[....] Starting OpenBSD Secure Shell server: sshd[   19.664938] random: sshd: uninitialized urandom read (32 bytes read)
[?25l[?1c7[ ok 8[?25h[?0c.

Debian GNU/Linux 7 syzkaller ttyS0

syzkaller login: [   23.655527] random: sshd: uninitialized urandom read (32 bytes read)
[   23.965650] random: sshd: uninitialized urandom read (32 bytes read)
[   24.851576] random: sshd: uninitialized urandom read (32 bytes read)
[   25.011506] random: sshd: uninitialized urandom read (32 bytes read)
Warning: Permanently added '10.128.0.62' (ECDSA) to the list of known hosts.
[   30.485419] random: sshd: uninitialized urandom read (32 bytes read)
executing program
[   30.586972] ==================================================================
[   30.594496] BUG: KASAN: use-after-free in _copy_to_user+0xe9/0x110
[   30.600801] Read of size 924 at addr ffff8801a7fffff2 by task syz-executor242/4575
[   30.608491] 
[   30.610163] CPU: 0 PID: 4575 Comm: syz-executor242 Not tainted 4.18.0-rc3+ #4
[   30.617430] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
[   30.627126] Call Trace:
[   30.629723]  dump_stack+0x1c9/0x2b4
[   30.633352]  ? dump_stack_print_info.cold.2+0x52/0x52
[   30.638550]  ? printk+0xa7/0xcf
[   30.641855]  ? kmsg_dump_rewind_nolock+0xe4/0xe4
[   30.646653]  ? _copy_to_user+0xe9/0x110
[   30.650647]  print_address_description+0x6c/0x20b
[   30.655510]  ? _copy_to_user+0xe9/0x110
[   30.659488]  kasan_report.cold.7+0x242/0x2fe
[   30.663911]  check_memory_region+0x13e/0x1b0
[   30.668327]  kasan_check_read+0x11/0x20
[   30.672304]  _copy_to_user+0xe9/0x110
[   30.676132]  bpf_test_finish.isra.7+0xee/0x1f0
[   30.680717]  ? bpf_test_init.isra.8+0x100/0x100
[   30.685404]  ? bpf_test_run+0x2fc/0x3b0
[   30.689415]  bpf_prog_test_run_skb+0x7d7/0xa30
[   30.693998]  ? bpf_test_finish.isra.7+0x1f0/0x1f0
[   30.698840]  ? __sanitizer_cov_trace_const_cmp4+0x16/0x20
[   30.704363]  ? __bpf_prog_get+0x9b/0x290
[   30.708410]  ? bpf_test_finish.isra.7+0x1f0/0x1f0
[   30.713330]  bpf_prog_test_run+0x130/0x1a0
[   30.717562]  __x64_sys_bpf+0x3d8/0x510
[   30.721441]  ? bpf_prog_get+0x20/0x20
[   30.725242]  ? do_syscall_64+0x9a/0x820
[   30.729215]  do_syscall_64+0x1b9/0x820
[   30.733133]  ? syscall_return_slowpath+0x5e0/0x5e0
[   30.738068]  ? syscall_return_slowpath+0x31d/0x5e0
[   30.743801]  ? entry_SYSCALL_64_after_hwframe+0x59/0xbe
[   30.749514]  ? trace_hardirqs_off_thunk+0x1a/0x1c
[   30.754651]  entry_SYSCALL_64_after_hwframe+0x49/0xbe
[   30.759838] RIP: 0033:0x440269
[   30.763027] Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 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 fb 13 fc ff c3 66 2e 0f 1f 84 00 00 00 00 
[   30.782249] RSP: 002b:00007ffd410d6238 EFLAGS: 00000213 ORIG_RAX: 0000000000000141
[   30.789978] RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 0000000000440269
[   30.797238] RDX: 0000000000000028 RSI: 0000000020000380 RDI: 000000000000000a
[   30.804508] RBP: 00000000006ca018 R08: 00000000004002c8 R09: 00000000004002c8
[   30.811800] R10: 0000000000000000 R11: 0000000000000213 R12: 0000000000401af0
[   30.819067] R13: 0000000000401b80 R14: 0000000000000000 R15: 0000000000000000
[   30.826352] 
[   30.827964] The buggy address belongs to the page:
[   30.832882] page:ffffea00069fffc0 count:0 mapcount:0 mapping:0000000000000000 index:0x0
[   30.841027] flags: 0x2fffc0000000000()
[   30.844926] raw: 02fffc0000000000 ffffea00069fffc8 ffffea00069fffc8 0000000000000000
[   30.852815] raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
[   30.860698] page dumped because: kasan: bad access detected
[   30.866421] 
[   30.868037] Memory state around the buggy address:
[   30.872965]  ffff8801a7fffe80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[   30.880333]  ffff8801a7ffff00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[   30.887705] >ffff8801a7ffff80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[   30.895061]                                                              ^
[   30.902312]  ffff8801a8000000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
[   30.910024]  ffff8801a8000080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
[   30.917619] ==================================================================
[   30.924974] Disabling lock debugging due to kernel taint
[   30.930488] Kernel panic - not syncing: panic_on_warn set ...
[   30.930488] 
[   30.937981] CPU: 0 PID: 4575 Comm: syz-executor242 Tainted: G    B             4.18.0-rc3+ #4
[   30.946854] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
[   30.956398] Call Trace:
[   30.958999]  dump_stack+0x1c9/0x2b4
[   30.962630]  ? dump_stack_print_info.cold.2+0x52/0x52
[   30.967831]  ? trace_hardirqs_on_thunk+0x1a/0x1c
[   30.972719]  panic+0x238/0x4e7
[   30.975907]  ? add_taint.cold.5+0x16/0x16
[   30.980072]  ? do_raw_spin_unlock+0xa7/0x2f0
[   30.984514]  ? do_raw_spin_unlock+0xa7/0x2f0
[   30.989003]  ? _copy_to_user+0xe9/0x110
[   30.992985]  kasan_end_report+0x47/0x4f
[   30.996962]  kasan_report.cold.7+0x76/0x2fe
[   31.001276]  check_memory_region+0x13e/0x1b0
[   31.005682]  kasan_check_read+0x11/0x20
[   31.009649]  _copy_to_user+0xe9/0x110
[   31.013450]  bpf_test_finish.isra.7+0xee/0x1f0
[   31.018054]  ? bpf_test_init.isra.8+0x100/0x100
[   31.022736]  ? bpf_test_run+0x2fc/0x3b0
[   31.026720]  bpf_prog_test_run_skb+0x7d7/0xa30
[   31.031318]  ? bpf_test_finish.isra.7+0x1f0/0x1f0
[   31.036174]  ? __sanitizer_cov_trace_const_cmp4+0x16/0x20
[   31.041708]  ? __bpf_prog_get+0x9b/0x290
[   31.045764]  ? bpf_test_finish.isra.7+0x1f0/0x1f0
[   31.050603]  bpf_prog_test_run+0x130/0x1a0
[   31.054838]  __x64_sys_bpf+0x3d8/0x510
[   31.058728]  ? bpf_prog_get+0x20/0x20
[   31.062621]  ? do_syscall_64+0x9a/0x820
[   31.066610]  do_syscall_64+0x1b9/0x820
[   31.070488]  ? syscall_return_slowpath+0x5e0/0x5e0
[   31.075419]  ? syscall_return_slowpath+0x31d/0x5e0
[   31.080365]  ? entry_SYSCALL_64_after_hwframe+0x59/0xbe
[   31.085753]  ? trace_hardirqs_off_thunk+0x1a/0x1c
[   31.090606]  entry_SYSCALL_64_after_hwframe+0x49/0xbe
[   31.095790] RIP: 0033:0x440269
[   31.098961] Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 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 fb 13 fc ff c3 66 2e 0f 1f 84 00 00 00 00 
[   31.118282] RSP: 002b:00007ffd410d6238 EFLAGS: 00000213 ORIG_RAX: 0000000000000141
[   31.125987] RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 0000000000440269
[   31.133267] RDX: 0000000000000028 RSI: 0000000020000380 RDI: 000000000000000a
[   31.140546] RBP: 00000000006ca018 R08: 00000000004002c8 R09: 00000000004002c8
[   31.147805] R10: 0000000000000000 R11: 0000000000000213 R12: 0000000000401af0
[   31.155060] R13: 0000000000401b80 R14: 0000000000000000 R15: 0000000000000000
[   31.162905] Dumping ftrace buffer:
[   31.166431]    (ftrace buffer empty)
[   31.170125] Kernel Offset: disabled
[   31.173740] Rebooting in 86400 seconds..