[....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. Starting mcstransd: [....] Starting file context maintaining daemon: restorecond[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 10.087587] random: sshd: uninitialized urandom read (32 bytes read) [?25l[?1c7[ ok 8[?25h[?0c. [ 11.126104] random: crng init done Debian GNU/Linux 7 syzkaller ttyS0 Warning: Permanently added '10.128.10.0' (ECDSA) to the list of known hosts. executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program syzkaller login: [ 53.019267] ================================================================== [ 53.020717] BUG: KASAN: use-after-free in disk_unblock_events+0x51/0x60 [ 53.021660] Read of size 8 at addr ffff8801ce68a760 by task blkid/2073 [ 53.022601] [ 53.022848] CPU: 1 PID: 2073 Comm: blkid Not tainted 4.9.133+ #54 [ 53.023758] ffff8801ce62f6f8 ffffffff81b37069 ffffea000739a200 ffff8801ce68a760 [ 53.025096] 0000000000000000 ffff8801ce68a760 0000000000000000 ffff8801ce62f730 [ 53.026426] ffffffff81500a0d ffff8801ce68a760 0000000000000008 0000000000000000 [ 53.027704] Call Trace: [ 53.028084] [] dump_stack+0xc1/0x128 [ 53.028913] [] print_address_description+0x6c/0x234 [ 53.029895] [] kasan_report.cold.6+0x242/0x2fe [ 53.030753] [] ? disk_unblock_events+0x51/0x60 [ 53.031685] [] __asan_report_load8_noabort+0x14/0x20 [ 53.032679] [] disk_unblock_events+0x51/0x60 [ 53.033775] [] __blkdev_get+0x6b6/0xd60 [ 53.034852] [] ? __blkdev_put+0x840/0x840 [ 53.035915] [] ? fsnotify+0x114/0x1100 [ 53.037103] [] blkdev_get+0x2da/0x920 [ 53.038189] [] ? debug_lockdep_rcu_enabled+0x77/0x90 [ 53.040189] [] ? bd_may_claim+0xd0/0xd0 [ 53.045809] [] ? bd_acquire+0x27/0x250 [ 53.051353] [] ? bd_acquire+0x88/0x250 [ 53.056893] [] ? _raw_spin_unlock+0x2c/0x50 [ 53.062859] [] blkdev_open+0x1a5/0x250 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 53.068399] [] do_dentry_open+0x3ef/0xc90 [ 53.074189] [] ? blkdev_get_by_dev+0x70/0x70 [ 53.080244] [] vfs_open+0x11c/0x210 [ 53.085515] [] ? may_open.isra.20+0x14f/0x2a0 [ 53.091656] [] path_openat+0x542/0x2790 [ 53.097278] [] ? path_mountpoint+0x6c0/0x6c0 [ 53.103344] [] ? trace_hardirqs_on+0x10/0x10 [ 53.109404] [] ? expand_files.part.3+0x3a9/0x6d0 executing program executing program executing program executing program executing program executing program [ 53.115803] [] do_filp_open+0x197/0x270 [ 53.121420] [] ? may_open_dev+0xe0/0xe0 [ 53.127037] [] ? _raw_spin_unlock+0x2c/0x50 [ 53.133038] [] ? __alloc_fd+0x1d7/0x4a0 [ 53.138659] [] do_sys_open+0x30d/0x5c0 [ 53.144192] [] ? filp_open+0x70/0x70 [ 53.149551] [] ? up_read+0x1a/0x40 [ 53.154740] [] SyS_open+0x2d/0x40 [ 53.159837] [] ? do_sys_open+0x5c0/0x5c0 [ 53.165543] [] do_syscall_64+0x19f/0x550 [ 53.171250] [] entry_SYSCALL_64_after_swapgs+0x5d/0xdb [ 53.178164] [ 53.179781] Allocated by task 2062: [ 53.183405] save_stack_trace+0x16/0x20 [ 53.187369] kasan_kmalloc.part.1+0x62/0xf0 [ 53.191684] kasan_kmalloc+0xaf/0xc0 [ 53.195389] kmem_cache_alloc_trace+0x117/0x2e0 [ 53.200051] alloc_disk_node+0x54/0x3a0 [ 53.204016] alloc_disk+0x18/0x20 [ 53.207463] loop_add+0x368/0x7a0 [ 53.210913] loop_control_ioctl+0x136/0x300 [ 53.215227] do_vfs_ioctl+0x1ac/0x11a0 [ 53.219109] SyS_ioctl+0x8f/0xc0 [ 53.222469] do_syscall_64+0x19f/0x550 [ 53.226361] entry_SYSCALL_64_after_swapgs+0x5d/0xdb [ 53.231451] [ 53.233068] Freed by task 2073: [ 53.236354] save_stack_trace+0x16/0x20 [ 53.240340] kasan_slab_free+0xac/0x190 [ 53.244312] kfree+0xfb/0x310 [ 53.247419] disk_release+0x259/0x330 [ 53.251214] device_release+0x7e/0x220 [ 53.255090] kobject_put+0x148/0x250 [ 53.258794] put_disk+0x23/0x30 [ 53.262071] __blkdev_get+0x616/0xd60 [ 53.265868] blkdev_get+0x2da/0x920 [ 53.269494] blkdev_open+0x1a5/0x250 [ 53.273204] do_dentry_open+0x3ef/0xc90 [ 53.277172] vfs_open+0x11c/0x210 [ 53.280618] path_openat+0x542/0x2790 [ 53.284410] do_filp_open+0x197/0x270 [ 53.288205] do_sys_open+0x30d/0x5c0 [ 53.291916] SyS_open+0x2d/0x40 [ 53.295193] do_syscall_64+0x19f/0x550 [ 53.299077] entry_SYSCALL_64_after_swapgs+0x5d/0xdb [ 53.304165] [ 53.305789] The buggy address belongs to the object at ffff8801ce68a200 [ 53.305789] which belongs to the cache kmalloc-2048 of size 2048 [ 53.318615] The buggy address is located 1376 bytes inside of [ 53.318615] 2048-byte region [ffff8801ce68a200, ffff8801ce68aa00) [ 53.330652] The buggy address belongs to the page: [ 53.335574] page:ffffea000739a200 count:1 mapcount:0 mapping: (null) index:0x0 compound_mapcount: 0 [ 53.345790] flags: 0x4000000000004080(slab|head) [ 53.350531] page dumped because: kasan: bad access detected [ 53.356230] [ 53.357850] Memory state around the buggy address: [ 53.362779] ffff8801ce68a600: 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 [ 53.370133] ffff8801ce68a680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 53.377484] >ffff8801ce68a700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 53.384833] ^ [ 53.391336] ffff8801ce68a780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 53.398687] ffff8801ce68a800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 53.406037] ================================================================== [ 53.413383] 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 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 53.423957] Kernel panic - not syncing: panic_on_warn set ... [ 53.423957] [ 53.431345] CPU: 1 PID: 2073 Comm: blkid Tainted: G B 4.9.133+ #54 [ 53.438789] ffff8801ce62f658 ffffffff81b37069 ffffffff82e359a0 00000000ffffffff [ 53.446874] 0000000000000000 0000000000000001 0000000000000000 ffff8801ce62f718 [ 53.454948] ffffffff813f6a45 0000000041b58ab3 ffffffff82e299a3 ffffffff813f6886 [ 53.463035] Call Trace: [ 53.465618] [] dump_stack+0xc1/0x128 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 53.470976] [] panic+0x1bf/0x39f [ 53.475988] [] ? add_taint.cold.6+0x16/0x16 [ 53.481958] [] ? ___preempt_schedule+0x16/0x18 [ 53.488188] [] kasan_end_report+0x47/0x4f [ 53.493985] [] kasan_report.cold.6+0x76/0x2fe [ 53.500127] [] ? disk_unblock_events+0x51/0x60 [ 53.506364] [] __asan_report_load8_noabort+0x14/0x20 [ 53.513114] [] disk_unblock_events+0x51/0x60 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 53.519170] [] __blkdev_get+0x6b6/0xd60 [ 53.524789] [] ? __blkdev_put+0x840/0x840 [ 53.530586] [] ? fsnotify+0x114/0x1100 [ 53.536116] [] blkdev_get+0x2da/0x920 [ 53.541564] [] ? debug_lockdep_rcu_enabled+0x77/0x90 [ 53.548315] [] ? bd_may_claim+0xd0/0xd0 [ 53.553944] [] ? bd_acquire+0x27/0x250 [ 53.559475] [] ? bd_acquire+0x88/0x250 [ 53.565010] [] ? _raw_spin_unlock+0x2c/0x50 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 53.570975] [] blkdev_open+0x1a5/0x250 [ 53.576509] [] do_dentry_open+0x3ef/0xc90 [ 53.582303] [] ? blkdev_get_by_dev+0x70/0x70 [ 53.588365] [] vfs_open+0x11c/0x210 [ 53.593637] [] ? may_open.isra.20+0x14f/0x2a0 [ 53.599776] [] path_openat+0x542/0x2790 [ 53.605397] [] ? path_mountpoint+0x6c0/0x6c0 [ 53.611449] [] ? trace_hardirqs_on+0x10/0x10 [ 53.617506] [] ? expand_files.part.3+0x3a9/0x6d0 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 53.623908] [] do_filp_open+0x197/0x270 [ 53.629529] [] ? may_open_dev+0xe0/0xe0 [ 53.635153] [] ? _raw_spin_unlock+0x2c/0x50 [ 53.641121] [] ? __alloc_fd+0x1d7/0x4a0 [ 53.646742] [] do_sys_open+0x30d/0x5c0 [ 53.652272] [] ? filp_open+0x70/0x70 [ 53.657629] [] ? up_read+0x1a/0x40 [ 53.662811] [] SyS_open+0x2d/0x40 [ 53.667918] [] ? do_sys_open+0x5c0/0x5c0 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 53.673628] [] do_syscall_64+0x19f/0x550 [ 53.679348] [] entry_SYSCALL_64_after_swapgs+0x5d/0xdb [ 53.686652] Kernel Offset: disabled [ 53.690262] Rebooting in 86400 seconds..