[....] Starting OpenBSD Secure Shell server: sshd[ 9.497856] random: sshd: uninitialized urandom read (32 bytes read) [?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 26.398941] random: sshd: uninitialized urandom read (32 bytes read) [ 26.819937] audit: type=1400 audit(1552592049.712:6): avc: denied { map } for pid=1769 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 [ 26.888755] random: sshd: uninitialized urandom read (32 bytes read) [ 27.429177] random: sshd: uninitialized urandom read (32 bytes read) [ 27.618536] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.0.44' (ECDSA) to the list of known hosts. [ 43.109976] random: sshd: uninitialized urandom read (32 bytes read) executing program executing program executing program executing program executing program executing program [ 43.199777] audit: type=1400 audit(1552592066.092:7): avc: denied { map } for pid=1793 comm="syz-executor100" path="/root/syz-executor100814139" 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 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 58.974443] ================================================================== [ 58.981911] BUG: KASAN: use-after-free in disk_unblock_events+0x4b/0x50 [ 58.988667] Read of size 8 at addr ffff8881c6bee2e8 by task syz-executor100/4340 [ 58.996209] [ 58.997845] CPU: 0 PID: 4340 Comm: syz-executor100 Not tainted 4.14.106+ #30 [ 59.005286] Call Trace: [ 59.007883] dump_stack+0xb9/0x10e [ 59.011428] ? disk_unblock_events+0x4b/0x50 [ 59.015844] print_address_description+0x60/0x226 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 59.020698] ? disk_unblock_events+0x4b/0x50 [ 59.025125] kasan_report.cold+0x88/0x2a5 [ 59.029289] ? disk_unblock_events+0x4b/0x50 [ 59.033699] ? __blkdev_get+0x68f/0xf90 [ 59.037681] ? finish_task_switch+0x1b7/0x620 [ 59.042181] ? __switch_to_asm+0x40/0x70 [ 59.046253] ? __blkdev_put+0x6d0/0x6d0 [ 59.050232] ? __schedule+0x924/0x1f30 [ 59.054142] ? blkdev_get+0x97/0x8b0 [ 59.057862] ? bd_acquire+0x171/0x2c0 [ 59.061666] ? bd_may_claim+0xd0/0xd0 [ 59.065465] ? lock_downgrade+0x5d0/0x5d0 [ 59.069617] ? lock_acquire+0x10f/0x380 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 59.073594] ? bd_acquire+0x21/0x2c0 [ 59.077322] ? blkdev_open+0x1cc/0x250 [ 59.081227] ? do_dentry_open+0x41b/0xd60 [ 59.085381] ? bd_acquire+0x2c0/0x2c0 [ 59.089201] ? vfs_open+0x105/0x230 [ 59.092834] ? path_openat+0xb6b/0x2b70 [ 59.096823] ? path_mountpoint+0x9a0/0x9a0 [ 59.101064] ? trace_hardirqs_on+0x10/0x10 [ 59.105324] ? do_filp_open+0x1a1/0x280 [ 59.109303] ? may_open_dev+0xe0/0xe0 [ 59.113128] ? lock_downgrade+0x5d0/0x5d0 [ 59.117456] ? lock_acquire+0x10f/0x380 [ 59.121439] ? __alloc_fd+0x3f/0x490 executing program executing program executing program executing program executing program [ 59.125163] ? _raw_spin_unlock+0x29/0x40 [ 59.129324] ? __alloc_fd+0x1bf/0x490 [ 59.133140] ? do_sys_open+0x2ca/0x590 [ 59.137032] ? filp_open+0x60/0x60 [ 59.140574] ? lock_downgrade+0x5d0/0x5d0 [ 59.144730] ? lock_acquire+0x10f/0x380 [ 59.148707] ? _raw_spin_unlock_irq+0x24/0x50 [ 59.153217] ? do_syscall_64+0x43/0x4b0 [ 59.157200] ? do_sys_open+0x590/0x590 [ 59.161108] ? do_syscall_64+0x19b/0x4b0 [ 59.165186] ? entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 59.170593] executing program executing program executing program executing program executing program executing program [ 59.172218] Allocated by task 4315: [ 59.175848] kasan_kmalloc.part.0+0x4f/0xd0 [ 59.180167] kmem_cache_alloc_trace+0x126/0x310 [ 59.184841] alloc_disk_node+0x5b/0x3d0 [ 59.188808] [ 59.190432] Freed by task 4340: [ 59.193716] kasan_slab_free+0xb0/0x190 [ 59.197692] kfree+0xf5/0x310 [ 59.200801] device_release+0xf4/0x1a0 [ 59.204681] [ 59.206305] The buggy address belongs to the object at ffff8881c6bedd80 [ 59.206305] which belongs to the cache kmalloc-2048 of size 2048 [ 59.219141] The buggy address is located 1384 bytes inside of executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 59.219141] 2048-byte region [ffff8881c6bedd80, ffff8881c6bee580) [ 59.231274] The buggy address belongs to the page: [ 59.236214] page:ffffea00071afa00 count:1 mapcount:0 mapping: (null) index:0x0 compound_mapcount: 0 [ 59.246183] flags: 0x4000000000008100(slab|head) [ 59.250953] raw: 4000000000008100 0000000000000000 0000000000000000 00000001000f000f [ 59.258837] raw: dead000000000100 dead000000000200 ffff8881da802800 0000000000000000 [ 59.266740] page dumped because: kasan: bad access detected [ 59.272558] executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 59.274181] Memory state around the buggy address: [ 59.279127] ffff8881c6bee180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 59.286492] ffff8881c6bee200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 59.293850] >ffff8881c6bee280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 59.301216] ^ [ 59.307971] ffff8881c6bee300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 59.315329] ffff8881c6bee380: 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 [ 59.322681] ================================================================== [ 59.330036] Disabling lock debugging due to kernel taint [ 59.336934] Kernel panic - not syncing: panic_on_warn set ... [ 59.336934] [ 59.344291] CPU: 0 PID: 4340 Comm: syz-executor100 Tainted: G B 4.14.106+ #30 [ 59.352766] Call Trace: [ 59.355360] dump_stack+0xb9/0x10e [ 59.358902] panic+0x1d9/0x3c2 [ 59.362107] ? add_taint.cold+0x16/0x16 [ 59.366083] ? disk_unblock_events+0x4b/0x50 [ 59.370504] ? ___preempt_schedule+0x16/0x18 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 59.375693] ? disk_unblock_events+0x4b/0x50 [ 59.380111] kasan_end_report+0x43/0x49 [ 59.384091] kasan_report.cold+0xa4/0x2a5 [ 59.388251] ? disk_unblock_events+0x4b/0x50 [ 59.392660] ? __blkdev_get+0x68f/0xf90 [ 59.396640] ? finish_task_switch+0x1b7/0x620 [ 59.401136] ? __switch_to_asm+0x40/0x70 [ 59.405202] ? __blkdev_put+0x6d0/0x6d0 [ 59.409176] ? __schedule+0x924/0x1f30 [ 59.413069] ? blkdev_get+0x97/0x8b0 [ 59.416800] ? bd_acquire+0x171/0x2c0 [ 59.420603] ? bd_may_claim+0xd0/0xd0 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 59.424491] ? lock_downgrade+0x5d0/0x5d0 [ 59.428638] ? lock_acquire+0x10f/0x380 [ 59.432618] ? bd_acquire+0x21/0x2c0 [ 59.436341] ? blkdev_open+0x1cc/0x250 [ 59.440232] ? do_dentry_open+0x41b/0xd60 [ 59.444378] ? bd_acquire+0x2c0/0x2c0 [ 59.448195] ? vfs_open+0x105/0x230 [ 59.451828] ? path_openat+0xb6b/0x2b70 [ 59.455806] ? path_mountpoint+0x9a0/0x9a0 [ 59.460045] ? trace_hardirqs_on+0x10/0x10 [ 59.464287] ? do_filp_open+0x1a1/0x280 [ 59.468263] ? may_open_dev+0xe0/0xe0 [ 59.472072] ? lock_downgrade+0x5d0/0x5d0 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 59.476231] ? lock_acquire+0x10f/0x380 [ 59.480213] ? __alloc_fd+0x3f/0x490 [ 59.483958] ? _raw_spin_unlock+0x29/0x40 [ 59.488118] ? __alloc_fd+0x1bf/0x490 [ 59.491925] ? do_sys_open+0x2ca/0x590 [ 59.495815] ? filp_open+0x60/0x60 [ 59.499357] ? lock_downgrade+0x5d0/0x5d0 [ 59.503507] ? lock_acquire+0x10f/0x380 [ 59.507488] ? _raw_spin_unlock_irq+0x24/0x50 [ 59.511993] ? do_syscall_64+0x43/0x4b0 [ 59.515973] ? do_sys_open+0x590/0x590 [ 59.519863] ? do_syscall_64+0x19b/0x4b0 executing program [ 59.523934] ? entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 59.529829] Kernel Offset: 0x15800000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff) [ 59.540779] Rebooting in 86400 seconds..