[....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 25.147613] random: sshd: uninitialized urandom read (32 bytes read) [?25l[?1c7[ ok 8[?25h[?0c. [ 25.577600] random: sshd: uninitialized urandom read (32 bytes read) [ 25.840821] random: sshd: uninitialized urandom read (32 bytes read) [ 26.417511] random: sshd: uninitialized urandom read (32 bytes read) Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 26.615008] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.15.212' (ECDSA) to the list of known hosts. [ 32.151420] random: sshd: uninitialized urandom read (32 bytes read) executing program [ 32.252125] divide error: 0000 [#1] SMP KASAN [ 32.256658] CPU: 0 PID: 4683 Comm: syz-executor884 Not tainted 4.19.0-rc1-next-20180831+ #53 [ 32.265414] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 32.274766] RIP: 0010:nbd_ioctl+0x53c/0xcf0 [ 32.279096] 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 [ 32.297982] RSP: 0018:ffff8801cf2ff828 EFLAGS: 00010246 [ 32.303329] RAX: 0000000000000000 RBX: 0000000000000001 RCX: 0000000000000000 [ 32.310592] RDX: 0000000000000000 RSI: ffff8801cdd25440 RDI: ffff8801cdd25500 [ 32.317850] RBP: ffff8801cf2ff9a0 R08: ffff8801bce800c0 R09: ffffed003a62710d [ 32.325126] R10: ffff8801cf2ff818 R11: ffff8801d313886f R12: ffff8801d3138780 [ 32.332377] R13: 00000000ffffffe7 R14: ffff8801d3138860 R15: ffff8801da806040 [ 32.339648] FS: 0000000001a8e880(0000) GS:ffff8801db000000(0000) knlGS:0000000000000000 [ 32.347854] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 32.353735] CR2: 000000000043e560 CR3: 00000001d0758000 CR4: 00000000001406f0 [ 32.361005] Call Trace: [ 32.363596] ? nbd_release+0x140/0x140 [ 32.367488] ? kasan_check_read+0x11/0x20 [ 32.371657] ? rcu_is_watching+0x8c/0x150 [ 32.375787] ? rcu_cleanup_dead_rnp+0x200/0x200 [ 32.380437] ? rcu_cleanup_dead_rnp+0x200/0x200 [ 32.385094] ? is_bpf_text_address+0xd7/0x170 [ 32.389592] ? nbd_release+0x140/0x140 [ 32.393488] blkdev_ioctl+0x9cd/0x2030 [ 32.397387] ? unwind_get_return_address+0x61/0xa0 [ 32.402300] ? blkpg_ioctl+0xc40/0xc40 [ 32.406174] ? save_stack+0xa9/0xd0 [ 32.409785] ? save_stack+0x43/0xd0 [ 32.413394] ? __kasan_slab_free+0x11a/0x170 [ 32.417972] ? kasan_slab_free+0xe/0x10 [ 32.421935] ? kmem_cache_free+0x86/0x280 [ 32.426070] ? putname+0xf2/0x130 [ 32.429510] ? do_sys_open+0x569/0x720 [ 32.433383] ? __x64_sys_open+0x7e/0xc0 [ 32.437342] ? do_syscall_64+0x1b9/0x820 [ 32.441397] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 32.446786] ? trace_hardirqs_off+0xb8/0x2b0 [ 32.451183] ? kasan_check_read+0x11/0x20 [ 32.455334] ? do_raw_spin_unlock+0xa7/0x2f0 [ 32.459728] ? trace_hardirqs_on+0x2c0/0x2c0 [ 32.464119] ? kasan_check_write+0x14/0x20 [ 32.468353] block_ioctl+0xee/0x130 [ 32.471977] ? blkdev_fallocate+0x400/0x400 [ 32.476284] do_vfs_ioctl+0x1de/0x1720 [ 32.480159] ? kasan_check_read+0x11/0x20 [ 32.484292] ? rcu_is_watching+0x8c/0x150 [ 32.488421] ? trace_hardirqs_on+0xbd/0x2c0 [ 32.492831] ? ioctl_preallocate+0x300/0x300 [ 32.497226] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 32.502747] ? __fget_light+0x2f7/0x440 [ 32.506703] ? putname+0xf2/0x130 [ 32.510139] ? fget_raw+0x20/0x20 [ 32.513914] ? rcu_read_lock_sched_held+0x108/0x120 [ 32.518912] ? kmem_cache_free+0x246/0x280 [ 32.523131] ? do_syscall_64+0x9a/0x820 [ 32.527089] ? do_syscall_64+0x9a/0x820 [ 32.531063] ? lockdep_hardirqs_on+0x421/0x5c0 [ 32.535645] ? security_file_ioctl+0x94/0xc0 [ 32.540052] ksys_ioctl+0xa9/0xd0 [ 32.543516] __x64_sys_ioctl+0x73/0xb0 [ 32.547390] do_syscall_64+0x1b9/0x820 [ 32.551264] ? entry_SYSCALL_64_after_hwframe+0x3e/0xbe [ 32.556611] ? syscall_return_slowpath+0x5e0/0x5e0 [ 32.561526] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 32.566367] ? trace_hardirqs_on_caller+0x2b0/0x2b0 [ 32.571368] ? prepare_exit_to_usermode+0x3b0/0x3b0 [ 32.576371] ? prepare_exit_to_usermode+0x291/0x3b0 [ 32.581373] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 32.586203] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 32.591382] RIP: 0033:0x443d29 [ 32.594729] 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 [ 32.613613] RSP: 002b:00007ffc48d89fc8 EFLAGS: 00000213 ORIG_RAX: 0000000000000010 [ 32.621303] RAX: ffffffffffffffda RBX: 00000000004002e0 RCX: 0000000000443d29 [ 32.628557] RDX: 0000000000000000 RSI: 000000000000ab01 RDI: 0000000000000003 [ 32.635829] RBP: 00000000006ce018 R08: 0000000000000000 R09: 00000000004002e0 [ 32.643101] R10: 000000000000000f R11: 0000000000000213 R12: 0000000000401a30 [ 32.650354] R13: 0000000000401ac0 R14: 0000000000000000 R15: 0000000000000000 [ 32.657610] Modules linked in: [ 32.660789] Dumping ftrace buffer: [ 32.664321] (ftrace buffer empty) [ 32.668166] ---[ end trace 1285902012ded5d4 ]--- [ 32.672971] RIP: 0010:nbd_ioctl+0x53c/0xcf0 [ 32.677316] 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 [ 32.696249] RSP: 0018:ffff8801cf2ff828 EFLAGS: 00010246 [ 32.701628] RAX: 0000000000000000 RBX: 0000000000000001 RCX: 0000000000000000 [ 32.708912] RDX: 0000000000000000 RSI: ffff8801cdd25440 RDI: ffff8801cdd25500 [ 32.716195] RBP: ffff8801cf2ff9a0 R08: ffff8801bce800c0 R09: ffffed003a62710d [ 32.723490] R10: ffff8801cf2ff818 R11: ffff8801d313886f R12: ffff8801d3138780 [ 32.730783] R13: 00000000ffffffe7 R14: ffff8801d3138860 R15: ffff8801da806040 [ 32.738067] FS: 0000000001a8e880(0000) GS:ffff8801db000000(0000) knlGS:0000000000000000 [ 32.746311] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 32.752206] CR2: 000000000043e560 CR3: 00000001d0758000 CR4: 00000000001406f0 [ 32.759721] Kernel panic - not syncing: Fatal exception [ 32.765391] Dumping ftrace buffer: [ 32.768924] (ftrace buffer empty) [ 32.772612] Kernel Offset: disabled [ 32.776226] Rebooting in 86400 seconds..