[....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 13.790299] random: sshd: uninitialized urandom read (32 bytes read) [?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 25.203590] random: sshd: uninitialized urandom read (32 bytes read) [ 25.452329] random: sshd: uninitialized urandom read (32 bytes read) [ 25.887823] random: sshd: uninitialized urandom read (32 bytes read) [ 40.715560] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.0.11' (ECDSA) to the list of known hosts. [ 46.356144] random: sshd: uninitialized urandom read (32 bytes read) executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 49.466277] ================================================================== [ 49.473671] BUG: KASAN: use-after-free in disk_unblock_events+0x4b/0x50 [ 49.480397] Read of size 8 at addr ffff8801b802e2e8 by task blkid/2732 [ 49.487041] [ 49.488669] CPU: 1 PID: 2732 Comm: blkid Not tainted 4.14.67+ #1 [ 49.494802] Call Trace: [ 49.497391] dump_stack+0xb9/0x11b [ 49.500938] print_address_description+0x60/0x22b [ 49.505791] kasan_report.cold.6+0x11b/0x2dd [ 49.510202] ? disk_unblock_events+0x4b/0x50 [ 49.514608] disk_unblock_events+0x4b/0x50 [ 49.518841] __blkdev_get+0x68f/0xe50 [ 49.522640] ? trace_hardirqs_on+0x10/0x10 [ 49.526878] ? __blkdev_put+0x6e0/0x6e0 [ 49.530855] ? check_preemption_disabled+0x34/0x160 [ 49.535877] ? fsnotify+0x639/0x12d0 [ 49.539596] blkdev_get+0x97/0x8c0 [ 49.543139] ? bd_may_claim+0xe0/0xe0 [ 49.546934] ? bd_acquire+0x171/0x2c0 [ 49.550734] ? lock_downgrade+0x560/0x560 [ 49.554884] ? lock_acquire+0x10f/0x380 [ 49.558854] ? bd_acquire+0x21/0x2c0 [ 49.562576] blkdev_open+0x1bd/0x240 [ 49.566288] ? security_file_open+0x88/0x190 [ 49.570697] do_dentry_open+0x426/0xda0 [ 49.574687] ? bd_acquire+0x2c0/0x2c0 [ 49.578504] vfs_open+0x11c/0x210 [ 49.581961] path_openat+0x4eb/0x23a0 [ 49.585790] ? path_mountpoint+0x9a0/0x9a0 [ 49.590040] ? kasan_kmalloc.part.1+0x4f/0xd0 [ 49.594537] ? trace_hardirqs_on+0x10/0x10 [ 49.598801] do_filp_open+0x197/0x270 [ 49.602606] ? may_open_dev+0xd0/0xd0 [ 49.606424] ? _raw_spin_unlock+0x29/0x40 [ 49.610582] do_sys_open+0x2ef/0x580 [ 49.614338] ? filp_open+0x60/0x60 [ 49.617875] ? up_read+0x17/0x30 [ 49.621244] ? __do_page_fault+0x64c/0xb60 [ 49.625482] ? do_syscall_64+0x43/0x4b0 [ 49.629455] ? do_sys_open+0x580/0x580 [ 49.633340] do_syscall_64+0x19b/0x4b0 [ 49.637232] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 49.642415] RIP: 0033:0x7f77479a2120 [ 49.646117] RSP: 002b:00007fff5103b1f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000002 [ 49.653823] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f77479a2120 [ 49.661090] RDX: 00007fff5103cf35 RSI: 0000000000000000 RDI: 00007fff5103cf35 [ 49.668357] RBP: 0000000000000000 R08: 0000000000000078 R09: 0000000000000000 [ 49.675620] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000aad030 [ 49.682914] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000005 [ 49.690284] [ 49.691904] Allocated by task 2715: [ 49.695533] kasan_kmalloc.part.1+0x4f/0xd0 [ 49.699854] kmem_cache_alloc_trace+0x138/0x300 [ 49.704520] alloc_disk_node+0x5f/0x3b0 [ 49.708494] loop_add+0x3e9/0x840 [ 49.711945] loop_probe+0x14f/0x180 [ 49.715570] kobj_lookup+0x230/0x420 [ 49.719276] get_gendisk+0x32/0x230 [ 49.722900] __blkdev_get+0x345/0xe50 [ 49.726694] blkdev_get+0x456/0x8c0 [ 49.730319] blkdev_open+0x1bd/0x240 [ 49.734025] do_dentry_open+0x426/0xda0 [ 49.738006] vfs_open+0x11c/0x210 [ 49.741457] path_openat+0x4eb/0x23a0 [ 49.745251] do_filp_open+0x197/0x270 [ 49.749049] do_sys_open+0x2ef/0x580 [ 49.752756] do_syscall_64+0x19b/0x4b0 [ 49.756649] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 49.761851] [ 49.763472] Freed by task 2732: [ 49.766756] kasan_slab_free+0xac/0x190 [ 49.770733] kfree+0xf5/0x310 [ 49.773842] device_release+0xf4/0x1a0 [ 49.777729] kobject_put+0x146/0x200 [ 49.781431] put_disk+0x1f/0x30 [ 49.784707] __blkdev_get+0x5fa/0xe50 [ 49.788500] blkdev_get+0x97/0x8c0 [ 49.792035] blkdev_open+0x1bd/0x240 [ 49.795752] do_dentry_open+0x426/0xda0 [ 49.799725] vfs_open+0x11c/0x210 [ 49.803173] path_openat+0x4eb/0x23a0 [ 49.806966] do_filp_open+0x197/0x270 [ 49.810784] do_sys_open+0x2ef/0x580 [ 49.814493] do_syscall_64+0x19b/0x4b0 [ 49.818380] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 49.823556] [ 49.825176] The buggy address belongs to the object at ffff8801b802dd80 [ 49.825176] which belongs to the cache kmalloc-2048 of size 2048 [ 49.838046] The buggy address is located 1384 bytes inside of [ 49.838046] 2048-byte region [ffff8801b802dd80, ffff8801b802e580) [ 49.850089] The buggy address belongs to the page: [ 49.855021] page:ffffea0006e00a00 count:1 mapcount:0 mapping: (null) index:0x0 compound_mapcount: 0 [ 49.864985] flags: 0x4000000000008100(slab|head) [ 49.869752] raw: 4000000000008100 0000000000000000 0000000000000000 00000001000f000f [ 49.877664] raw: dead000000000100 dead000000000200 ffff8801d6402800 0000000000000000 [ 49.885537] page dumped because: kasan: bad access detected [ 49.891235] [ 49.892857] Memory state around the buggy address: [ 49.897789] ffff8801b802e180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 49.905140] ffff8801b802e200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 49.912492] >ffff8801b802e280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 49.919844] ^ [ 49.926591] ffff8801b802e300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 49.933941] ffff8801b802e380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 49.941288] ================================================================== [ 49.948634] Disabling lock debugging due to kernel taint executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 49.982813] Kernel panic - not syncing: panic_on_warn set ... [ 49.982813] [ 49.990188] CPU: 1 PID: 2732 Comm: blkid Tainted: G B 4.14.67+ #1 [ 49.997533] Call Trace: [ 50.000118] dump_stack+0xb9/0x11b [ 50.003657] panic+0x1bf/0x3a4 [ 50.006852] ? add_taint.cold.4+0x16/0x16 [ 50.011011] ? ___preempt_schedule+0x16/0x18 [ 50.015426] kasan_end_report+0x43/0x49 [ 50.019398] kasan_report.cold.6+0x77/0x2dd [ 50.023714] ? disk_unblock_events+0x4b/0x50 [ 50.028117] disk_unblock_events+0x4b/0x50 [ 50.032345] __blkdev_get+0x68f/0xe50 [ 50.036145] ? trace_hardirqs_on+0x10/0x10 [ 50.040375] ? __blkdev_put+0x6e0/0x6e0 [ 50.044347] ? check_preemption_disabled+0x34/0x160 [ 50.049384] ? fsnotify+0x639/0x12d0 [ 50.053108] blkdev_get+0x97/0x8c0 [ 50.056646] ? bd_may_claim+0xe0/0xe0 [ 50.060440] ? bd_acquire+0x171/0x2c0 [ 50.064234] ? lock_downgrade+0x560/0x560 [ 50.068375] ? lock_acquire+0x10f/0x380 [ 50.072339] ? bd_acquire+0x21/0x2c0 [ 50.076055] blkdev_open+0x1bd/0x240 [ 50.079774] ? security_file_open+0x88/0x190 [ 50.084180] do_dentry_open+0x426/0xda0 [ 50.088152] ? bd_acquire+0x2c0/0x2c0 [ 50.091949] vfs_open+0x11c/0x210 [ 50.095396] path_openat+0x4eb/0x23a0 [ 50.099199] ? path_mountpoint+0x9a0/0x9a0 [ 50.103430] ? kasan_kmalloc.part.1+0x4f/0xd0 [ 50.107919] ? trace_hardirqs_on+0x10/0x10 [ 50.112158] do_filp_open+0x197/0x270 [ 50.115953] ? may_open_dev+0xd0/0xd0 [ 50.119755] ? _raw_spin_unlock+0x29/0x40 [ 50.123920] do_sys_open+0x2ef/0x580 [ 50.127629] ? filp_open+0x60/0x60 [ 50.131166] ? up_read+0x17/0x30 [ 50.134530] ? __do_page_fault+0x64c/0xb60 [ 50.138762] ? do_syscall_64+0x43/0x4b0 [ 50.142741] ? do_sys_open+0x580/0x580 [ 50.146640] do_syscall_64+0x19b/0x4b0 [ 50.150521] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 50.155704] RIP: 0033:0x7f77479a2120 [ 50.159405] RSP: 002b:00007fff5103b1f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000002 [ 50.167106] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f77479a2120 [ 50.174371] RDX: 00007fff5103cf35 RSI: 0000000000000000 RDI: 00007fff5103cf35 [ 50.181635] RBP: 0000000000000000 R08: 0000000000000078 R09: 0000000000000000 [ 50.188897] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000aad030 [ 50.196160] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000005 [ 50.203740] Dumping ftrace buffer: [ 50.207271] (ftrace buffer empty) [ 50.210958] Kernel Offset: 0x1d000000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff) [ 50.221850] Rebooting in 86400 seconds..