[....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c.
[....] Starting OpenBSD Secure Shell server: sshd[   19.438349] random: sshd: uninitialized urandom read (32 bytes read)
[?25l[?1c7[ ok 8[?25h[?0c.

Debian GNU/Linux 7 syzkaller ttyS0

syzkaller login: [   23.925733] random: sshd: uninitialized urandom read (32 bytes read)
[   24.256143] random: sshd: uninitialized urandom read (32 bytes read)
[   25.119206] random: sshd: uninitialized urandom read (32 bytes read)
[   25.273901] random: sshd: uninitialized urandom read (32 bytes read)
Warning: Permanently added '10.128.0.5' (ECDSA) to the list of known hosts.
[   30.688268] random: sshd: uninitialized urandom read (32 bytes read)
executing program
[   30.788114] ==================================================================
[   30.795599] BUG: KASAN: use-after-free in _copy_to_user+0xe9/0x110
[   30.801913] Read of size 924 at addr ffff8801a7bffff2 by task syz-executor980/4529
[   30.809600] 
[   30.811221] CPU: 1 PID: 4529 Comm: syz-executor980 Not tainted 4.18.0-rc4+ #141
[   30.818690] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
[   30.828091] Call Trace:
[   30.830694]  dump_stack+0x1c9/0x2b4
[   30.834334]  ? dump_stack_print_info.cold.2+0x52/0x52
[   30.839507]  ? printk+0xa7/0xcf
[   30.842785]  ? kmsg_dump_rewind_nolock+0xe4/0xe4
[   30.847533]  ? _copy_to_user+0xe9/0x110
[   30.851508]  print_address_description+0x6c/0x20b
[   30.856346]  ? _copy_to_user+0xe9/0x110
[   30.860318]  kasan_report.cold.7+0x242/0x2fe
[   30.864731]  check_memory_region+0x13e/0x1b0
[   30.869151]  kasan_check_read+0x11/0x20
[   30.873126]  _copy_to_user+0xe9/0x110
[   30.876934]  bpf_test_finish.isra.7+0xee/0x1f0
[   30.881536]  ? bpf_test_init.isra.8+0x100/0x100
[   30.886200]  ? bpf_test_run+0x2fc/0x3b0
[   30.890167]  bpf_prog_test_run_skb+0x7d7/0xa30
[   30.894738]  ? bpf_test_finish.isra.7+0x1f0/0x1f0
[   30.899583]  ? __sanitizer_cov_trace_const_cmp4+0x16/0x20
[   30.905109]  ? __bpf_prog_get+0x9b/0x290
[   30.909165]  ? bpf_test_finish.isra.7+0x1f0/0x1f0
[   30.914014]  bpf_prog_test_run+0x130/0x1a0
[   30.918254]  __x64_sys_bpf+0x3d8/0x510
[   30.922135]  ? bpf_prog_get+0x20/0x20
[   30.925949]  ? do_syscall_64+0x9a/0x820
[   30.929921]  do_syscall_64+0x1b9/0x820
[   30.933807]  ? syscall_return_slowpath+0x5e0/0x5e0
[   30.938729]  ? syscall_return_slowpath+0x31d/0x5e0
[   30.943655]  ? entry_SYSCALL_64_after_hwframe+0x59/0xbe
[   30.949021]  ? trace_hardirqs_off_thunk+0x1a/0x1c
[   30.953871]  entry_SYSCALL_64_after_hwframe+0x49/0xbe
[   30.959083] RIP: 0033:0x440269
[   30.962280] 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 
[   30.981579] RSP: 002b:00007ffc3555f7b8 EFLAGS: 00000213 ORIG_RAX: 0000000000000141
[   30.989290] RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 0000000000440269
[   30.996547] RDX: 0000000000000028 RSI: 0000000020000380 RDI: 000000000000000a
[   31.003798] RBP: 00000000006ca018 R08: 00000000004002c8 R09: 00000000004002c8
[   31.011070] R10: 0000000000000000 R11: 0000000000000213 R12: 0000000000401af0
[   31.018341] R13: 0000000000401b80 R14: 0000000000000000 R15: 0000000000000000
[   31.025618] 
[   31.027228] The buggy address belongs to the page:
[   31.032145] page:ffffea00069effc0 count:0 mapcount:0 mapping:0000000000000000 index:0x0
[   31.040289] flags: 0x2fffc0000000000()
[   31.044178] raw: 02fffc0000000000 ffffea00069effc8 ffffea00069effc8 0000000000000000
[   31.052067] raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
[   31.059944] page dumped because: kasan: bad access detected
[   31.065648] 
[   31.067275] Memory state around the buggy address:
[   31.072207]  ffff8801a7bffe80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[   31.079559]  ffff8801a7bfff00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[   31.086921] >ffff8801a7bfff80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[   31.094277]                                                              ^
[   31.101279]  ffff8801a7c00000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
[   31.108631]  ffff8801a7c00080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
[   31.115979] ==================================================================
[   31.123330] Disabling lock debugging due to kernel taint
[   31.128833] Kernel panic - not syncing: panic_on_warn set ...
[   31.128833] 
[   31.136207] CPU: 1 PID: 4529 Comm: syz-executor980 Tainted: G    B             4.18.0-rc4+ #141
[   31.145043] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
[   31.154388] Call Trace:
[   31.156970]  dump_stack+0x1c9/0x2b4
[   31.160585]  ? dump_stack_print_info.cold.2+0x52/0x52
[   31.165764]  ? trace_hardirqs_on_thunk+0x1a/0x1c
[   31.170515]  panic+0x238/0x4e7
[   31.173703]  ? add_taint.cold.5+0x16/0x16
[   31.177854]  ? do_raw_spin_unlock+0xa7/0x2f0
[   31.182268]  ? do_raw_spin_unlock+0xa7/0x2f0
[   31.186677]  ? _copy_to_user+0xe9/0x110
[   31.190634]  kasan_end_report+0x47/0x4f
[   31.194598]  kasan_report.cold.7+0x76/0x2fe
[   31.198924]  check_memory_region+0x13e/0x1b0
[   31.203338]  kasan_check_read+0x11/0x20
[   31.207322]  _copy_to_user+0xe9/0x110
[   31.211136]  bpf_test_finish.isra.7+0xee/0x1f0
[   31.215722]  ? bpf_test_init.isra.8+0x100/0x100
[   31.220432]  ? bpf_test_run+0x2fc/0x3b0
[   31.224422]  bpf_prog_test_run_skb+0x7d7/0xa30
[   31.229012]  ? bpf_test_finish.isra.7+0x1f0/0x1f0
[   31.233859]  ? __sanitizer_cov_trace_const_cmp4+0x16/0x20
[   31.239388]  ? __bpf_prog_get+0x9b/0x290
[   31.243437]  ? bpf_test_finish.isra.7+0x1f0/0x1f0
[   31.248276]  bpf_prog_test_run+0x130/0x1a0
[   31.252514]  __x64_sys_bpf+0x3d8/0x510
[   31.256392]  ? bpf_prog_get+0x20/0x20
[   31.260191]  ? do_syscall_64+0x9a/0x820
[   31.264160]  do_syscall_64+0x1b9/0x820
[   31.268054]  ? syscall_return_slowpath+0x5e0/0x5e0
[   31.272971]  ? syscall_return_slowpath+0x31d/0x5e0
[   31.277894]  ? entry_SYSCALL_64_after_hwframe+0x59/0xbe
[   31.283279]  ? trace_hardirqs_off_thunk+0x1a/0x1c
[   31.288144]  entry_SYSCALL_64_after_hwframe+0x49/0xbe
[   31.293322] RIP: 0033:0x440269
[   31.296492] 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 
[   31.315624] RSP: 002b:00007ffc3555f7b8 EFLAGS: 00000213 ORIG_RAX: 0000000000000141
[   31.323347] RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 0000000000440269
[   31.330614] RDX: 0000000000000028 RSI: 0000000020000380 RDI: 000000000000000a
[   31.337874] RBP: 00000000006ca018 R08: 00000000004002c8 R09: 00000000004002c8
[   31.345134] R10: 0000000000000000 R11: 0000000000000213 R12: 0000000000401af0
[   31.352395] R13: 0000000000401b80 R14: 0000000000000000 R15: 0000000000000000
[   31.360141] Dumping ftrace buffer:
[   31.363670]    (ftrace buffer empty)
[   31.367365] Kernel Offset: disabled
[   31.370985] Rebooting in 86400 seconds..