[....] Starting enhanced syslogd: rsyslogd[ 10.205545] audit: type=1400 audit(1514402857.474:4): avc: denied { syslog } for pid=3172 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 '10.128.0.20' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 20.348900] ================================================================== [ 20.350041] BUG: KASAN: use-after-free in __lock_acquire+0x2eff/0x3640 [ 20.350961] Read of size 8 at addr ffff8801ccb9cd38 by task syzkaller884844/3325 [ 20.351945] [ 20.352174] CPU: 0 PID: 3325 Comm: syzkaller884844 Not tainted 4.9.72-gcb7518e #114 [ 20.353203] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 20.354641] ffff8801c1d678c0 ffffffff81d922b9 ffffea000732e700 ffff8801ccb9cd38 [ 20.355830] 0000000000000000 ffff8801ccb9cd38 ffff8801ccb9cd38 ffff8801c1d678f8 [ 20.356999] ffffffff8153bab3 ffff8801ccb9cd38 0000000000000008 0000000000000000 [ 20.358167] Call Trace: [ 20.358526] [] dump_stack+0xc1/0x128 [ 20.359253] [] print_address_description+0x73/0x280 [ 20.360140] [] kasan_report+0x275/0x360 [ 20.360882] [] ? __lock_acquire+0x2eff/0x3640 [ 20.361700] [] __asan_report_load8_noabort+0x14/0x20 [ 20.362585] [] __lock_acquire+0x2eff/0x3640 [ 20.363379] [] ? __lock_acquire+0x629/0x3640 [ 20.364197] [] ? debug_check_no_locks_freed+0x2c0/0x2c0 [ 20.365130] [] ? debug_check_no_locks_freed+0x2c0/0x2c0 [ 20.366071] [] ? __lock_is_held+0xa1/0xf0 [ 20.366865] [] lock_acquire+0x12e/0x410 [ 20.367604] [] ? remove_wait_queue+0x14/0x40 [ 20.368401] [] _raw_spin_lock_irqsave+0x4e/0x70 [ 20.370881] [] ? remove_wait_queue+0x14/0x40 [ 20.376904] [] remove_wait_queue+0x14/0x40 [ 20.382758] [] ep_unregister_pollwait.isra.6+0xaf/0x240 [ 20.389744] [] ? ep_unregister_pollwait.isra.6+0x12a/0x240 [ 20.396997] [] ep_remove+0x41/0x290 [ 20.402250] [] eventpoll_release_file+0xc5/0x140 [ 20.408628] [] __fput+0x5a8/0x6e0 [ 20.413697] [] ____fput+0x15/0x20 [ 20.418769] [] task_work_run+0x115/0x190 [ 20.424456] [] do_exit+0x7e7/0x2a40 [ 20.429701] [] ? selinux_file_ioctl+0x355/0x530 [ 20.435995] [] ? release_task+0x1240/0x1240 [ 20.441934] [] ? SyS_epoll_create+0x190/0x190 [ 20.448049] [] ? entry_SYSCALL_64_fastpath+0x5/0xc6 [ 20.454692] [] do_group_exit+0x108/0x320 [ 20.460369] [] SyS_exit_group+0x1d/0x20 [ 20.465973] [] entry_SYSCALL_64_fastpath+0x23/0xc6 [ 20.472513] [ 20.474111] Allocated by task 3325: [ 20.477705] save_stack_trace+0x16/0x20 [ 20.481661] save_stack+0x43/0xd0 [ 20.485078] kasan_kmalloc+0xad/0xe0 [ 20.488756] kmem_cache_alloc_trace+0xfb/0x2a0 [ 20.493306] binder_get_thread+0x15d/0x750 [ 20.497509] binder_poll+0x4a/0x210 [ 20.501107] SyS_epoll_ctl+0x11d7/0x2190 [ 20.505135] entry_SYSCALL_64_fastpath+0x23/0xc6 [ 20.509859] [ 20.511459] Freed by task 3325: [ 20.514845] save_stack_trace+0x16/0x20 [ 20.518885] save_stack+0x43/0xd0 [ 20.522330] kasan_slab_free+0x72/0xc0 [ 20.526187] kfree+0x103/0x300 [ 20.529360] binder_thread_dec_tmpref+0x1cc/0x240 [ 20.534167] binder_thread_release+0x27d/0x540 [ 20.538801] binder_ioctl+0x9c0/0x11b0 [ 20.542670] do_vfs_ioctl+0x1aa/0x1140 [ 20.546531] SyS_ioctl+0x8f/0xc0 [ 20.549880] entry_SYSCALL_64_fastpath+0x23/0xc6 [ 20.554602] [ 20.556196] The buggy address belongs to the object at ffff8801ccb9cc80 [ 20.556196] which belongs to the cache kmalloc-512 of size 512 [ 20.568829] The buggy address is located 184 bytes inside of [ 20.568829] 512-byte region [ffff8801ccb9cc80, ffff8801ccb9ce80) [ 20.580666] The buggy address belongs to the page: [ 20.585562] page:ffffea000732e700 count:1 mapcount:0 mapping: (null) index:0x0 compound_mapcount: 0 [ 20.595902] flags: 0x8000000000004080(slab|head) [ 20.600618] page dumped because: kasan: bad access detected [ 20.606302] [ 20.607897] Memory state around the buggy address: [ 20.612790] ffff8801ccb9cc00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 20.620113] ffff8801ccb9cc80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 20.627445] >ffff8801ccb9cd00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 20.634768] ^ [ 20.639920] ffff8801ccb9cd80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 20.647263] ffff8801ccb9ce00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 20.654585] ================================================================== [ 20.661910] Disabling lock debugging due to kernel taint [ 20.667325] Kernel panic - not syncing: panic_on_warn set ... [ 20.667325] [ 20.674654] CPU: 0 PID: 3325 Comm: syzkaller884844 Tainted: G B 4.9.72-gcb7518e #114 [ 20.683626] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 20.692950] ffff8801c1d67818 ffffffff81d922b9 ffffffff841955bf ffff8801c1d678f0 [ 20.700921] 0000000000000000 ffff8801ccb9cd38 ffff8801ccb9cd38 ffff8801c1d678e0 [ 20.708879] ffffffff8142d741 0000000041b58ab3 ffffffff84189000 ffffffff8142d585 [ 20.717000] Call Trace: [ 20.719561] [] dump_stack+0xc1/0x128 [ 20.724895] [] panic+0x1bc/0x3a8 [ 20.729880] [] ? percpu_up_read_preempt_enable.constprop.53+0xd7/0xd7 [ 20.738102] [] ? add_taint+0x40/0x50 [ 20.738110] [] kasan_end_report+0x50/0x50 [ 20.738113] [] kasan_report+0x167/0x360 [ 20.738122] [] ? __lock_acquire+0x2eff/0x3640 [ 20.738133] [] __asan_report_load8_noabort+0x14/0x20 [ 20.738137] [] __lock_acquire+0x2eff/0x3640 [ 20.738141] [] ? __lock_acquire+0x629/0x3640 [ 20.738146] [] ? debug_check_no_locks_freed+0x2c0/0x2c0 [ 20.738150] [] ? debug_check_no_locks_freed+0x2c0/0x2c0 [ 20.738154] [] ? __lock_is_held+0xa1/0xf0 [ 20.738158] [] lock_acquire+0x12e/0x410 [ 20.738162] [] ? remove_wait_queue+0x14/0x40 [ 20.738168] [] _raw_spin_lock_irqsave+0x4e/0x70 [ 20.738172] [] ? remove_wait_queue+0x14/0x40 [ 20.738175] [] remove_wait_queue+0x14/0x40 [ 20.738182] [] ep_unregister_pollwait.isra.6+0xaf/0x240 [ 20.738186] [] ? ep_unregister_pollwait.isra.6+0x12a/0x240 [ 20.738189] [] ep_remove+0x41/0x290 [ 20.738193] [] eventpoll_release_file+0xc5/0x140 [ 20.738200] [] __fput+0x5a8/0x6e0 [ 20.738204] [] ____fput+0x15/0x20 [ 20.738209] [] task_work_run+0x115/0x190 [ 20.738214] [] do_exit+0x7e7/0x2a40 [ 20.738222] [] ? selinux_file_ioctl+0x355/0x530 [ 20.738226] [] ? release_task+0x1240/0x1240 [ 20.738230] [] ? SyS_epoll_create+0x190/0x190 [ 20.738235] [] ? entry_SYSCALL_64_fastpath+0x5/0xc6 [ 20.738239] [] do_group_exit+0x108/0x320 [ 20.738243] [] SyS_exit_group+0x1d/0x20 [ 20.738247] [] entry_SYSCALL_64_fastpath+0x23/0xc6 [ 20.743540] Dumping ftrace buffer: [ 20.743544] (ftrace buffer empty) [ 20.743550] Kernel Offset: disabled [ 20.929763] Rebooting in 86400 seconds..