[....] Starting enhanced syslogd: rsyslogd[ 15.129159] audit: type=1400 audit(1559984546.138:4): avc: denied { syslog } for pid=1923 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[1G[[32m ok [39;49m8[?25h[?0c. [....] Starting periodic command scheduler: cron[?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c. Starting mcstransd: [....] Starting file context maintaining daemon: restorecond[?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 Warning: Permanently added '10.128.0.16' (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 syzkaller login: [ 56.108789] ================================================================== [ 56.116303] BUG: KASAN: use-after-free in disk_unblock_events+0x55/0x60 [ 56.123221] Read of size 8 at addr ffff8800b6658568 by task blkid/2107 [ 56.130001] [ 56.131624] CPU: 1 PID: 2107 Comm: blkid Not tainted 4.4.174+ #17 [ 56.137836] 0000000000000000 e68d831b4a90efda ffff8800b671f730 ffffffff81aad1a1 [ 56.145844] 0000000000000000 ffffea0002d99600 ffff8800b6658568 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 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 56.154052] 0000000000000000 ffff8800b671f768 ffffffff81490120 0000000000000000 [ 56.162203] Call Trace: [ 56.164828] [] dump_stack+0xc1/0x120 [ 56.170238] [] print_address_description+0x6f/0x21b [ 56.176943] [] kasan_report.cold+0x8c/0x2be [ 56.182906] [] ? disk_unblock_events+0x55/0x60 [ 56.189169] [] __asan_report_load8_noabort+0x14/0x20 [ 56.195924] [] disk_unblock_events+0x55/0x60 [ 56.202058] [] __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 [ 56.207775] [] ? __blkdev_put+0x840/0x840 [ 56.213567] [] ? trace_hardirqs_on+0x10/0x10 [ 56.219613] [] blkdev_get+0x2e8/0x920 [ 56.225047] [] ? bd_may_claim+0xd0/0xd0 [ 56.230655] [] ? bd_acquire+0x8a/0x370 [ 56.236182] [] ? _raw_spin_unlock+0x2d/0x50 [ 56.242200] [] blkdev_open+0x1aa/0x250 [ 56.247747] [] do_dentry_open+0x38f/0xbd0 [ 56.253595] [] ? __inode_permission2+0x9e/0x250 [ 56.259905] [] ? blkdev_get_by_dev+0x80/0x80 [ 56.266071] [] vfs_open+0x10b/0x210 [ 56.271354] [] ? may_open.isra.0+0xe7/0x210 [ 56.277356] [] path_openat+0x136f/0x4470 [ 56.283066] [] ? kasan_kmalloc.part.0+0xc6/0xf0 [ 56.289383] [] ? may_open.isra.0+0x210/0x210 [ 56.295437] [] ? trace_hardirqs_on+0x10/0x10 [ 56.301532] [] do_filp_open+0x1a1/0x270 [ 56.307157] [] ? user_path_mountpoint_at+0x50/0x50 [ 56.314031] [] ? __alloc_fd+0x1ea/0x490 [ 56.319794] [] ? _raw_spin_unlock+0x2d/0x50 [ 56.325813] [] do_sys_open+0x2f8/0x600 [ 56.331397] [] ? filp_open+0x70/0x70 [ 56.336759] [] ? retint_user+0x18/0x3c [ 56.348228] [] ? trace_hardirqs_on_caller+0x385/0x5a0 [ 56.355268] [] SyS_open+0x2d/0x40 [ 56.360372] [] entry_SYSCALL_64_fastpath+0x1e/0x9a [ 56.366933] [ 56.368542] Allocated by task 2101: [ 56.372322] [] save_stack_trace+0x26/0x50 [ 56.378265] [] kasan_kmalloc.part.0+0x62/0xf0 [ 56.378270] [] kasan_kmalloc+0xb7/0xd0 [ 56.378275] [] kmem_cache_alloc_trace+0x123/0x2d0 [ 56.378281] [] alloc_disk_node+0x50/0x3c0 [ 56.378286] [] alloc_disk+0x1b/0x20 [ 56.378297] [] loop_add+0x380/0x830 [ 56.378302] [] loop_control_ioctl+0x215/0x2f0 [ 56.378307] [] compat_SyS_ioctl+0x403/0x2210 [ 56.378314] [] do_fast_syscall_32+0x32d/0xa90 [ 56.378320] [] sysenter_flags_fixed+0xd/0x1a [ 56.378321] [ 56.378324] Freed by task 2107: [ 56.378329] [] save_stack_trace+0x26/0x50 [ 56.378333] [] kasan_slab_free+0xb0/0x190 [ 56.378337] [] kfree+0xf4/0x310 [ 56.378342] [] disk_release+0x255/0x330 [ 56.378347] [] device_release+0x7d/0x220 [ 56.378357] [] kobject_put+0x14c/0x260 [ 56.378362] [] put_disk+0x23/0x30 [ 56.378366] [] __blkdev_get+0x66c/0xdf0 [ 56.378370] [] blkdev_get+0x2e8/0x920 [ 56.378374] [] blkdev_open+0x1aa/0x250 [ 56.378380] [] do_dentry_open+0x38f/0xbd0 [ 56.378384] [] vfs_open+0x10b/0x210 [ 56.378389] [] path_openat+0x136f/0x4470 [ 56.378393] [] do_filp_open+0x1a1/0x270 [ 56.378397] [] do_sys_open+0x2f8/0x600 [ 56.378401] [] SyS_open+0x2d/0x40 [ 56.378406] [] entry_SYSCALL_64_fastpath+0x1e/0x9a [ 56.378407] [ 56.378410] The buggy address belongs to the object at ffff8800b6658000 [ 56.378410] which belongs to the cache kmalloc-2048 of size 2048 [ 56.378413] The buggy address is located 1384 bytes inside of [ 56.378413] 2048-byte region [ffff8800b6658000, ffff8800b6658800) [ 56.378415] The buggy address belongs to the page: [ 56.384523] kernel tried to execute NX-protected page - exploit attempt? (uid: 0) [ 56.384529] BUG: unable to handle kernel paging request at ffff8800b6617d90 [ 56.384536] IP: [] 0xffff8800b6617d90 [ 56.384542] PGD 49a2067 PUD 21ffff067 PMD 80000000b66001e3 [ 56.384547] Oops: 0011 [#1] PREEMPT SMP KASAN [ 56.384551] Modules linked in: [ 56.384556] CPU: 0 PID: 2281 Comm: init Not tainted 4.4.174+ #17 [ 56.384559] task: ffff8801d34c17c0 task.stack: ffff8801d3488000 [ 56.384564] RIP: 0010:[] [] 0xffff8800b6617d90 [ 56.384567] RSP: 0018:ffff8801db607dd8 EFLAGS: 00010006 [ 56.384569] RAX: ffff8801d34c17c0 RBX: ffff8800b6617d48 RCX: ffff8801d34c2088 [ 56.384572] RDX: 0000000000010000 RSI: ffffffff8125fa56 RDI: ffff8800b6617d48 [ 56.384574] RBP: ffff8801db607ee8 R08: 0000000000000003 R09: 0000000000000001 [ 56.384577] R10: 0000000000000000 R11: 0000000000000000 R12: ffff8800b6617d90 [ 56.384579] R13: dffffc0000000000 R14: ffff8801db6192c0 R15: 0000000000000000 [ 56.384583] FS: 00007f274e14e7a0(0000) GS:ffff8801db600000(0000) knlGS:0000000000000000 [ 56.384585] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 56.384588] CR2: ffff8800b6617d90 CR3: 00000001d47fe000 CR4: 00000000001606b0 [ 56.384592] Stack: [ 56.384597] ffffffff8125fa5e 0000000000000000 ffff8801db607e80 0000000000000002 [ 56.384602] 1ffff1003b6c0fc8 ffffed003b6c0fd0 ffff88021fffd01b 000000011fffd00f [ 56.384607] fffffbfff05f7178 ffff8801db619380 ffff8801db6192f8 ffff8801db619398 [ 56.384608] Call Trace: [ 56.384619] [ 56.384619] [] ? __hrtimer_run_queues+0x34e/0xfc0 [ 56.384624] [] ? hrtimer_fixup_init+0x70/0x70 [ 56.384629] [] ? kvm_clock_get_cycles+0x9/0x10 [ 56.384633] [] ? hrtimer_interrupt+0x121/0x450 [ 56.384637] [] hrtimer_interrupt+0x1b6/0x450 [ 56.384643] [] local_apic_timer_interrupt+0x76/0xa0 [ 56.384650] [] smp_apic_timer_interrupt+0x79/0xb0 [ 56.384654] [] apic_timer_interrupt+0x9d/0xb0 [ 56.384660] [ 56.384661] [] ? console_unlock+0x661/0xa10 [ 56.384666] [] ? uart_handle_cts_change+0x2a0/0x2a0 [ 56.384670] [] console_device+0x97/0xc0 [ 56.384676] [] tty_open+0x8e7/0xf50 [ 56.384681] [] ? tty_init_dev+0x420/0x420 [ 56.384687] [] ? chrdev_open+0xca/0x630 [ 56.384691] [] ? tty_init_dev+0x420/0x420 [ 56.384695] [] chrdev_open+0x230/0x630 [ 56.384699] [] ? cdev_put.part.0+0x50/0x50 [ 56.384705] [] do_dentry_open+0x38f/0xbd0 [ 56.384710] [] ? __inode_permission2+0x9e/0x250 [ 56.384714] [] ? cdev_put.part.0+0x50/0x50 [ 56.384717] [] vfs_open+0x10b/0x210 [ 56.384721] [] ? may_open.isra.0+0xe7/0x210 [ 56.384725] [] path_openat+0x136f/0x4470 [ 56.384729] [] ? kasan_kmalloc.part.0+0xc6/0xf0 [ 56.384733] [] ? may_open.isra.0+0x210/0x210 [ 56.384739] [] ? trace_hardirqs_on+0x10/0x10 [ 56.384743] [] do_filp_open+0x1a1/0x270 [ 56.384747] [] ? user_path_mountpoint_at+0x50/0x50 [ 56.384752] [] ? __alloc_fd+0x1ea/0x490 [ 56.384756] [] ? _raw_spin_unlock+0x2d/0x50 [ 56.384760] [] do_sys_open+0x2f8/0x600 [ 56.384763] [] ? filp_open+0x70/0x70 [ 56.384767] [] ? trace_hardirqs_on_caller+0x385/0x5a0 [ 56.384771] [] SyS_open+0x2d/0x40 [ 56.384775] [] entry_SYSCALL_64_fastpath+0x1e/0x9a [ 56.384830] Code: 88 ff ff 00 80 65 b6 00 88 ff ff 90 7d 61 b6 00 88 ff ff 50 ac 42 81 ff ff ff ff 00 96 d9 02 00 ea ff ff e0 1b 89 82 ff ff ff ff 7d 61 b6 00 88 ff ff 16 ac 42 81 ff ff ff ff 00 00 60 b7 00 [ 56.384833] RIP [] 0xffff8800b6617d90 [ 56.384834] RSP [ 56.384835] CR2: ffff8800b6617d90 [ 56.384839] ---[ end trace 54c4f42152d780e6 ]--- [ 56.384843] Kernel panic - not syncing: Fatal exception in interrupt [ 57.489385] Shutting down cpus with NMI [ 57.490173] Kernel Offset: disabled [ 58.085101] Rebooting in 86400 seconds..