[....] Starting OpenBSD Secure Shell server: sshd[ 11.062886] random: sshd: uninitialized urandom read (32 bytes read) [?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 25.850657] random: sshd: uninitialized urandom read (32 bytes read) [ 26.276347] audit: type=1400 audit(1543764830.652:6): avc: denied { map } for pid=1764 comm="bash" path="/bin/bash" dev="sda1" ino=1457 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 [ 26.321077] random: sshd: uninitialized urandom read (32 bytes read) [ 26.767948] random: sshd: uninitialized urandom read (32 bytes read) [ 26.924268] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.10.46' (ECDSA) to the list of known hosts. [ 32.470881] random: sshd: uninitialized urandom read (32 bytes read) executing program executing program executing program executing program executing program executing program [ 32.563831] audit: type=1400 audit(1543764836.942:7): avc: denied { map } for pid=1782 comm="syz-executor786" path="/root/syz-executor786589120" dev="sda1" ino=16481 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:object_r:user_home_t:s0 tclass=file permissive=1 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 37.480565] ================================================================== [ 37.488065] BUG: KASAN: use-after-free in disk_unblock_events+0x4b/0x50 [ 37.494810] Read of size 8 at addr ffff8881cc523868 by task blkid/2386 [ 37.501450] [ 37.503057] CPU: 0 PID: 2386 Comm: blkid Not tainted 4.14.85+ #15 [ 37.509265] Call Trace: [ 37.511881] dump_stack+0xb9/0x11b [ 37.515408] print_address_description+0x60/0x22b [ 37.520231] kasan_report.cold.6+0x11b/0x2dd [ 37.524626] ? disk_unblock_events+0x4b/0x50 [ 37.529014] disk_unblock_events+0x4b/0x50 [ 37.533228] __blkdev_get+0x68f/0xe50 [ 37.537011] ? __blkdev_put+0x6e0/0x6e0 [ 37.541010] ? check_preemption_disabled+0x34/0x1e0 [ 37.546014] ? fsnotify+0x773/0x1200 [ 37.549824] blkdev_get+0x97/0x8c0 [ 37.553585] ? bd_may_claim+0xe0/0xe0 [ 37.557470] ? bd_acquire+0x171/0x2c0 [ 37.561253] ? lock_downgrade+0x560/0x560 [ 37.565375] ? lock_acquire+0x10f/0x380 [ 37.569323] ? bd_acquire+0x21/0x2c0 [ 37.573029] blkdev_open+0x1bd/0x240 [ 37.576721] ? security_file_open+0x88/0x190 [ 37.581110] do_dentry_open+0x426/0xda0 [ 37.585059] ? bd_acquire+0x2c0/0x2c0 [ 37.588850] vfs_open+0x11c/0x210 [ 37.592407] path_openat+0x5f9/0x2930 [ 37.596197] ? path_mountpoint+0x9a0/0x9a0 [ 37.600421] ? kasan_kmalloc.part.1+0x4f/0xd0 [ 37.604910] ? trace_hardirqs_on+0x10/0x10 [ 37.609133] do_filp_open+0x197/0x270 [ 37.612916] ? may_open_dev+0xd0/0xd0 [ 37.616700] ? _raw_spin_unlock+0x29/0x40 [ 37.620843] do_sys_open+0x2ef/0x580 [ 37.624538] ? filp_open+0x60/0x60 [ 37.628084] ? up_read+0x17/0x30 [ 37.631427] ? __do_page_fault+0x64c/0xb60 [ 37.635646] ? do_syscall_64+0x43/0x4b0 [ 37.639597] ? do_sys_open+0x580/0x580 [ 37.643464] do_syscall_64+0x19b/0x4b0 [ 37.647338] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 37.652505] RIP: 0033:0x7f735043f120 [ 37.656202] RSP: 002b:00007ffc0f653ab8 EFLAGS: 00000246 ORIG_RAX: 0000000000000002 [ 37.663886] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f735043f120 [ 37.671185] RDX: 00007ffc0f654f45 RSI: 0000000000000000 RDI: 00007ffc0f654f45 [ 37.678439] RBP: 0000000000000000 R08: 0000000000000078 R09: 0000000000000000 [ 37.685688] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000001e51030 [ 37.692938] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000005 [ 37.700195] [ 37.701807] Allocated by task 2382: [ 37.705414] kasan_kmalloc.part.1+0x4f/0xd0 [ 37.709714] kmem_cache_alloc_trace+0x138/0x300 [ 37.714358] alloc_disk_node+0x5f/0x3b0 [ 37.718309] loop_add+0x3e9/0x840 [ 37.721736] loop_probe+0x14f/0x180 [ 37.725412] kobj_lookup+0x230/0x420 [ 37.729108] get_gendisk+0x32/0x230 [ 37.732712] __blkdev_get+0x345/0xe50 [ 37.736489] blkdev_get+0x456/0x8c0 [ 37.740100] blkdev_open+0x1bd/0x240 [ 37.743798] do_dentry_open+0x426/0xda0 [ 37.747744] vfs_open+0x11c/0x210 [ 37.751177] path_openat+0x5f9/0x2930 [ 37.754956] do_filp_open+0x197/0x270 [ 37.758733] do_sys_open+0x2ef/0x580 [ 37.762425] do_syscall_64+0x19b/0x4b0 [ 37.766287] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 37.771527] [ 37.773145] Freed by task 2386: [ 37.776407] kasan_slab_free+0xac/0x190 [ 37.780357] kfree+0xf5/0x310 [ 37.783437] device_release+0xf4/0x1a0 [ 37.787301] kobject_put+0x146/0x200 [ 37.790993] put_disk+0x1f/0x30 [ 37.794256] __blkdev_get+0x5fa/0xe50 [ 37.798038] blkdev_get+0x97/0x8c0 [ 37.801556] blkdev_open+0x1bd/0x240 [ 37.805314] do_dentry_open+0x426/0xda0 [ 37.809294] vfs_open+0x11c/0x210 [ 37.812729] path_openat+0x5f9/0x2930 [ 37.816513] do_filp_open+0x197/0x270 [ 37.820292] do_sys_open+0x2ef/0x580 [ 37.824117] do_syscall_64+0x19b/0x4b0 [ 37.827985] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 37.833149] [ 37.834753] The buggy address belongs to the object at ffff8881cc523300 [ 37.834753] which belongs to the cache kmalloc-2048 of size 2048 [ 37.847560] The buggy address is located 1384 bytes inside of [ 37.847560] 2048-byte region [ffff8881cc523300, ffff8881cc523b00) [ 37.859705] The buggy address belongs to the page: [ 37.864615] page:ffffea0007314800 count:1 mapcount:0 mapping: (null) index:0x0 compound_mapcount: 0 [ 37.874676] flags: 0x4000000000008100(slab|head) [ 37.879418] raw: 4000000000008100 0000000000000000 0000000000000000 00000001000f000f [ 37.887278] raw: dead000000000100 dead000000000200 ffff8881da802800 0000000000000000 [ 37.895135] page dumped because: kasan: bad access detected [ 37.900818] [ 37.902422] Memory state around the buggy address: [ 37.907326] ffff8881cc523700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 37.914669] ffff8881cc523780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 37.922010] >ffff8881cc523800: 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 [ 37.929347] ^ [ 37.936184] ffff8881cc523880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 37.943610] ffff8881cc523900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 37.950944] ================================================================== [ 37.958278] Disabling lock debugging due to kernel taint [ 37.966009] Kernel panic - not syncing: panic_on_warn set ... [ 37.966009] [ 37.973388] CPU: 0 PID: 2386 Comm: blkid Tainted: G B 4.14.85+ #15 [ 37.980820] Call Trace: [ 37.983388] dump_stack+0xb9/0x11b [ 37.986906] panic+0x1bf/0x3a4 [ 37.990076] ? add_taint.cold.4+0x16/0x16 [ 37.994208] ? ___preempt_schedule+0x16/0x18 [ 37.998598] kasan_end_report+0x43/0x49 [ 38.002552] kasan_report.cold.6+0x77/0x2dd [ 38.006851] ? disk_unblock_events+0x4b/0x50 [ 38.011237] disk_unblock_events+0x4b/0x50 [ 38.015452] __blkdev_get+0x68f/0xe50 [ 38.019229] ? __blkdev_put+0x6e0/0x6e0 [ 38.023193] ? check_preemption_disabled+0x34/0x1e0 [ 38.028322] ? fsnotify+0x773/0x1200 [ 38.032021] blkdev_get+0x97/0x8c0 [ 38.035539] ? bd_may_claim+0xe0/0xe0 [ 38.039416] ? bd_acquire+0x171/0x2c0 [ 38.043197] ? lock_downgrade+0x560/0x560 [ 38.047322] ? lock_acquire+0x10f/0x380 [ 38.051282] ? bd_acquire+0x21/0x2c0 [ 38.055055] blkdev_open+0x1bd/0x240 [ 38.058754] ? security_file_open+0x88/0x190 [ 38.063141] do_dentry_open+0x426/0xda0 [ 38.067089] ? bd_acquire+0x2c0/0x2c0 [ 38.070978] vfs_open+0x11c/0x210 [ 38.074414] path_openat+0x5f9/0x2930 [ 38.078188] ? path_mountpoint+0x9a0/0x9a0 [ 38.082399] ? kasan_kmalloc.part.1+0x4f/0xd0 [ 38.086871] ? trace_hardirqs_on+0x10/0x10 [ 38.091089] do_filp_open+0x197/0x270 [ 38.094867] ? may_open_dev+0xd0/0xd0 [ 38.098656] ? _raw_spin_unlock+0x29/0x40 [ 38.102787] do_sys_open+0x2ef/0x580 [ 38.106478] ? filp_open+0x60/0x60 [ 38.109994] ? up_read+0x17/0x30 [ 38.113353] ? __do_page_fault+0x64c/0xb60 [ 38.117566] ? do_syscall_64+0x43/0x4b0 [ 38.121516] ? do_sys_open+0x580/0x580 [ 38.125380] do_syscall_64+0x19b/0x4b0 [ 38.129249] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 38.134419] RIP: 0033:0x7f735043f120 [ 38.138103] RSP: 002b:00007ffc0f653ab8 EFLAGS: 00000246 ORIG_RAX: 0000000000000002 [ 38.145784] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f735043f120 [ 38.153029] RDX: 00007ffc0f654f45 RSI: 0000000000000000 RDI: 00007ffc0f654f45 [ 38.160282] RBP: 0000000000000000 R08: 0000000000000078 R09: 0000000000000000 [ 38.167528] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000001e51030 [ 38.174773] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000005 [ 38.182379] Kernel Offset: 0x25600000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff) [ 38.193399] Rebooting in 86400 seconds..