[....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 23.610424] random: sshd: uninitialized urandom read (32 bytes read) [?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 26.779808] random: sshd: uninitialized urandom read (32 bytes read) [ 27.156177] random: sshd: uninitialized urandom read (32 bytes read) [ 27.710537] random: sshd: uninitialized urandom read (32 bytes read) [ 27.887679] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.10.54' (ECDSA) to the list of known hosts. [ 33.561327] random: sshd: uninitialized urandom read (32 bytes read) executing program [ 33.659908] divide error: 0000 [#1] SMP KASAN [ 33.664441] CPU: 1 PID: 4659 Comm: syz-executor828 Not tainted 4.19.0-rc1-next-20180831+ #53 [ 33.672997] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 33.682342] RIP: 0010:nbd_ioctl+0x53c/0xcf0 [ 33.686649] Code: ea 03 80 3c 02 00 0f 85 1c 07 00 00 48 8b b5 c0 fe ff ff 48 63 8d b8 fe ff ff 48 8b 86 c8 00 00 00 48 8d be c0 00 00 00 48 99 <48> f7 f9 48 ba 00 00 00 00 00 fc ff df 48 89 f9 48 c1 e9 03 80 3c [ 33.705535] RSP: 0018:ffff8801b8c67828 EFLAGS: 00010246 [ 33.710880] RAX: 0000000000000000 RBX: 0000000000000001 RCX: 0000000000000000 [ 33.718138] RDX: 0000000000000000 RSI: ffff8801cdf9b040 RDI: ffff8801cdf9b100 [ 33.725398] RBP: ffff8801b8c679a0 R08: ffff8801bda12100 R09: ffffed003a62566d [ 33.732647] R10: ffff8801b8c67818 R11: ffff8801d312b36f R12: ffff8801d312b280 [ 33.739898] R13: 00000000ffffffe7 R14: ffff8801d312b360 R15: ffff8801ccc4c900 [ 33.747159] FS: 0000000000e6b880(0000) GS:ffff8801db100000(0000) knlGS:0000000000000000 [ 33.755369] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 33.761235] CR2: 000000000043e560 CR3: 00000001b9ad5000 CR4: 00000000001406e0 [ 33.768487] Call Trace: [ 33.771083] ? nbd_release+0x140/0x140 [ 33.774977] ? kasan_check_read+0x11/0x20 [ 33.779125] ? rcu_is_watching+0x8c/0x150 [ 33.783273] ? rcu_cleanup_dead_rnp+0x200/0x200 [ 33.787926] ? rcu_cleanup_dead_rnp+0x200/0x200 [ 33.792600] ? is_bpf_text_address+0xd7/0x170 [ 33.797109] ? nbd_release+0x140/0x140 [ 33.800999] blkdev_ioctl+0x9cd/0x2030 [ 33.804872] ? unwind_get_return_address+0x61/0xa0 [ 33.809839] ? blkpg_ioctl+0xc40/0xc40 [ 33.813721] ? save_stack+0xa9/0xd0 [ 33.817332] ? save_stack+0x43/0xd0 [ 33.820939] ? __kasan_slab_free+0x11a/0x170 [ 33.825346] ? kasan_slab_free+0xe/0x10 [ 33.829303] ? kmem_cache_free+0x86/0x280 [ 33.833439] ? putname+0xf2/0x130 [ 33.836877] ? do_sys_open+0x569/0x720 [ 33.840749] ? __x64_sys_open+0x7e/0xc0 [ 33.844708] ? do_syscall_64+0x1b9/0x820 [ 33.848753] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 33.854117] ? trace_hardirqs_off+0xb8/0x2b0 [ 33.858523] ? kasan_check_read+0x11/0x20 [ 33.862658] ? do_raw_spin_unlock+0xa7/0x2f0 [ 33.867050] ? trace_hardirqs_on+0x2c0/0x2c0 [ 33.871440] ? kasan_check_write+0x14/0x20 [ 33.875664] block_ioctl+0xee/0x130 [ 33.879287] ? blkdev_fallocate+0x400/0x400 [ 33.883591] do_vfs_ioctl+0x1de/0x1720 [ 33.887469] ? kasan_check_read+0x11/0x20 [ 33.891599] ? rcu_is_watching+0x8c/0x150 [ 33.895734] ? trace_hardirqs_on+0xbd/0x2c0 [ 33.900042] ? ioctl_preallocate+0x300/0x300 [ 33.904451] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 33.909972] ? __fget_light+0x2f7/0x440 [ 33.913929] ? putname+0xf2/0x130 [ 33.917367] ? fget_raw+0x20/0x20 [ 33.920808] ? rcu_read_lock_sched_held+0x108/0x120 [ 33.925810] ? kmem_cache_free+0x246/0x280 [ 33.930031] ? do_syscall_64+0x9a/0x820 [ 33.933990] ? do_syscall_64+0x9a/0x820 [ 33.937947] ? lockdep_hardirqs_on+0x421/0x5c0 [ 33.942528] ? security_file_ioctl+0x94/0xc0 [ 33.946921] ksys_ioctl+0xa9/0xd0 [ 33.950364] __x64_sys_ioctl+0x73/0xb0 [ 33.954238] do_syscall_64+0x1b9/0x820 [ 33.958132] ? entry_SYSCALL_64_after_hwframe+0x3e/0xbe [ 33.963489] ? syscall_return_slowpath+0x5e0/0x5e0 [ 33.968418] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 33.973267] ? trace_hardirqs_on_caller+0x2b0/0x2b0 [ 33.978323] ? prepare_exit_to_usermode+0x3b0/0x3b0 [ 33.983323] ? prepare_exit_to_usermode+0x291/0x3b0 [ 33.988326] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 33.993180] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 33.998351] RIP: 0033:0x443d29 [ 34.001552] 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 7b d8 fb ff c3 66 2e 0f 1f 84 00 00 00 00 [ 34.020436] RSP: 002b:00007ffdfeea6708 EFLAGS: 00000213 ORIG_RAX: 0000000000000010 [ 34.028136] RAX: ffffffffffffffda RBX: 00000000004002e0 RCX: 0000000000443d29 [ 34.035414] RDX: 0000000000000000 RSI: 000000000000ab01 RDI: 0000000000000003 [ 34.042682] RBP: 00000000006ce018 R08: 0000000000000000 R09: 00000000004002e0 [ 34.049943] R10: 000000000000000f R11: 0000000000000213 R12: 0000000000401a30 [ 34.057193] R13: 0000000000401ac0 R14: 0000000000000000 R15: 0000000000000000 [ 34.064485] Modules linked in: [ 34.067669] Dumping ftrace buffer: [ 34.071187] (ftrace buffer empty) [ 34.074967] ---[ end trace d08523d1fcd6ff07 ]--- [ 34.079754] RIP: 0010:nbd_ioctl+0x53c/0xcf0 [ 34.084132] Code: ea 03 80 3c 02 00 0f 85 1c 07 00 00 48 8b b5 c0 fe ff ff 48 63 8d b8 fe ff ff 48 8b 86 c8 00 00 00 48 8d be c0 00 00 00 48 99 <48> f7 f9 48 ba 00 00 00 00 00 fc ff df 48 89 f9 48 c1 e9 03 80 3c [ 34.103050] RSP: 0018:ffff8801b8c67828 EFLAGS: 00010246 [ 34.108430] RAX: 0000000000000000 RBX: 0000000000000001 RCX: 0000000000000000 [ 34.115714] RDX: 0000000000000000 RSI: ffff8801cdf9b040 RDI: ffff8801cdf9b100 [ 34.122995] RBP: ffff8801b8c679a0 R08: ffff8801bda12100 R09: ffffed003a62566d [ 34.130277] R10: ffff8801b8c67818 R11: ffff8801d312b36f R12: ffff8801d312b280 [ 34.137560] R13: 00000000ffffffe7 R14: ffff8801d312b360 R15: ffff8801ccc4c900 [ 34.144844] FS: 0000000000e6b880(0000) GS:ffff8801db100000(0000) knlGS:0000000000000000 [ 34.153116] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 34.159011] CR2: 000000000043e560 CR3: 00000001b9ad5000 CR4: 00000000001406e0 [ 34.166299] Kernel panic - not syncing: Fatal exception [ 34.171936] Dumping ftrace buffer: [ 34.175463] (ftrace buffer empty) [ 34.179149] Kernel Offset: disabled [ 34.182756] Rebooting in 86400 seconds..