[....] Starting enhanced syslogd: rsyslogd[ 13.988950] audit: type=1400 audit(1547480798.028:4): avc: denied { syslog } for pid=1918 comm="rsyslogd" capability=34 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:system_r:kernel_t:s0 tclass=capability2 permissive=1 [?25l[?1c7[ ok 8[?25h[?0c. Starting mcstransd: [....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting file context maintaining daemon: restorecond[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 Warning: Permanently added '10.128.0.254' (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 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program 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: [ 41.728891] ================================================================== [ 41.736336] BUG: KASAN: use-after-free in disk_unblock_events+0x55/0x60 [ 41.743094] Read of size 8 at addr ffff8800b31cafe8 by task blkid/2594 [ 41.749742] [ 41.751363] CPU: 0 PID: 2594 Comm: blkid Not tainted 4.4.170+ #4 [ 41.757492] 0000000000000000 66a6659c356ef30b ffff8800b2c87730 ffffffff81aaddc1 [ 41.765556] 0000000000000000 ffffea0002cc7200 ffff8800b31cafe8 0000000000000008 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 41.773615] 0000000000000000 ffff8800b2c87768 ffffffff8148fbed 0000000000000000 [ 41.781675] Call Trace: [ 41.784272] [] dump_stack+0xc1/0x120 [ 41.789629] [] print_address_description+0x6f/0x21b [ 41.796290] [] kasan_report.cold+0x8c/0x2be [ 41.802256] [] ? disk_unblock_events+0x55/0x60 [ 41.808492] [] __asan_report_load8_noabort+0x14/0x20 [ 41.815242] [] disk_unblock_events+0x55/0x60 [ 41.821296] [] __blkdev_get+0x70c/0xdf0 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 41.826914] [] ? __blkdev_put+0x840/0x840 [ 41.832720] [] ? trace_hardirqs_on+0x10/0x10 [ 41.838770] [] blkdev_get+0x2e8/0x920 [ 41.844217] [] ? bd_may_claim+0xd0/0xd0 [ 41.849834] [] ? bd_acquire+0x8a/0x370 [ 41.855365] [] ? _raw_spin_unlock+0x2d/0x50 [ 41.861343] [] blkdev_open+0x1aa/0x250 [ 41.866875] [] do_dentry_open+0x38f/0xbd0 [ 41.872665] [] ? __inode_permission2+0x9e/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 [ 41.878977] [] ? blkdev_get_by_dev+0x80/0x80 [ 41.885081] [] vfs_open+0x10b/0x210 [ 41.890350] [] ? may_open.isra.0+0xe7/0x210 [ 41.896313] [] path_openat+0x136f/0x4470 [ 41.902020] [] ? kasan_kmalloc.part.0+0xc6/0xf0 [ 41.908359] [] ? may_open.isra.0+0x210/0x210 [ 41.914413] [] ? trace_hardirqs_on+0x10/0x10 [ 41.920497] [] do_filp_open+0x1a1/0x270 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 41.926119] [] ? user_path_mountpoint_at+0x50/0x50 [ 41.932694] [] ? __alloc_fd+0x1ea/0x490 [ 41.938328] [] ? _raw_spin_unlock+0x2d/0x50 [ 41.944292] [] do_sys_open+0x2f8/0x600 [ 41.949822] [] ? filp_open+0x70/0x70 [ 41.955178] [] ? retint_user+0x18/0x3c [ 41.960709] [] ? trace_hardirqs_on_caller+0x385/0x5a0 [ 41.967540] [] SyS_open+0x2d/0x40 [ 41.972638] [] entry_SYSCALL_64_fastpath+0x1e/0x9a executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 41.979207] [ 41.980827] Allocated by task 2578: [ 41.984440] [] save_stack_trace+0x26/0x50 [ 41.990389] [] kasan_kmalloc.part.0+0x62/0xf0 [ 41.996658] [] kasan_kmalloc+0xb7/0xd0 [ 42.002370] [] kmem_cache_alloc_trace+0x123/0x2d0 [ 42.008981] [] alloc_disk_node+0x50/0x3c0 [ 42.014932] [] alloc_disk+0x1b/0x20 [ 42.020343] [] loop_add+0x384/0x7e0 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 42.025749] [] loop_probe+0x154/0x180 [ 42.031325] [] kobj_lookup+0x221/0x410 [ 42.036986] [] get_gendisk+0x3c/0x2e0 [ 42.042575] [] __blkdev_get+0x39c/0xdf0 [ 42.048348] [] blkdev_get+0x481/0x920 [ 42.053925] [] blkdev_open+0x1aa/0x250 [ 42.059590] [] do_dentry_open+0x38f/0xbd0 [ 42.065511] [] vfs_open+0x10b/0x210 [ 42.070950] [] path_openat+0x136f/0x4470 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 42.076788] [] do_filp_open+0x1a1/0x270 [ 42.082534] [] do_sys_open+0x2f8/0x600 [ 42.088199] [] SyS_open+0x2d/0x40 [ 42.093421] [] entry_SYSCALL_64_fastpath+0x1e/0x9a [ 42.100172] [ 42.101804] Freed by task 2594: [ 42.105071] [] save_stack_trace+0x26/0x50 [ 42.110994] [] kasan_slab_free+0xb0/0x190 [ 42.116926] [] kfree+0xf4/0x310 [ 42.121996] [] disk_release+0x255/0x330 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 42.127756] [] device_release+0x7d/0x220 [ 42.133637] [] kobject_put+0x14c/0x260 [ 42.139302] [] put_disk+0x23/0x30 [ 42.144539] [] __blkdev_get+0x66c/0xdf0 [ 42.150296] [] blkdev_get+0x2e8/0x920 [ 42.155874] [] blkdev_open+0x1aa/0x250 [ 42.161539] [] do_dentry_open+0x38f/0xbd0 [ 42.167476] [] vfs_open+0x10b/0x210 [ 42.172895] [] path_openat+0x136f/0x4470 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 42.178739] [] do_filp_open+0x1a1/0x270 [ 42.184492] [] do_sys_open+0x2f8/0x600 [ 42.190168] [] SyS_open+0x2d/0x40 [ 42.195402] [] entry_SYSCALL_64_fastpath+0x1e/0x9a [ 42.202166] [ 42.203788] The buggy address belongs to the object at ffff8800b31caa80 [ 42.203788] which belongs to the cache kmalloc-2048 of size 2048 [ 42.216618] The buggy address is located 1384 bytes inside of [ 42.216618] 2048-byte region [ffff8800b31caa80, ffff8800b31cb280) executing program [ 42.228663] The buggy address belongs to the page: [ 42.234598] kasan: CONFIG_KASAN_INLINE enabled [ 42.239105] kasan: CONFIG_KASAN_INLINE enabledkasan: GPF could be caused by NULL-ptr deref or user memory access [ 42.249759] ------------[ cut here ]------------ [ 42.254846] WARNING: CPU: 1 PID: 2073 at kernel/sched/core.c:7941 __might_sleep+0x138/0x1a0() [ 42.263537] do not call blocking ops when !TASK_RUNNING; state=1 set at [] do_wait+0x265/0xa00 [ 42.273867] Kernel panic - not syncing: panic_on_warn set ... [ 42.273867] [ 43.462106] Shutting down cpus with NMI [ 43.466453] Kernel Offset: disabled [ 43.470064] Rebooting in 86400 seconds..