[....] Starting enhanced syslogd: rsyslogd[ 10.306372] audit: type=1400 audit(1514490221.931:4): avc: denied { syslog } for pid=3171 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 '10.128.15.224' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 35.710644] ================================================================== [ 35.711721] BUG: KASAN: use-after-free in __lock_acquire+0x2eff/0x3640 [ 35.712598] Read of size 8 at addr ffff8801cc6ad238 by task syzkaller817846/3337 [ 35.713590] [ 35.713822] CPU: 0 PID: 3337 Comm: syzkaller817846 Not tainted 4.9.72-gcb7518e #114 [ 35.714838] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 35.716055] ffff8801c88bf8e0 ffffffff81d922b9 ffffea000731ab00 ffff8801cc6ad238 [ 35.717183] 0000000000000000 ffff8801cc6ad238 ffff8801cc6ad238 ffff8801c88bf918 [ 35.718309] ffffffff8153bab3 ffff8801cc6ad238 0000000000000008 0000000000000000 [ 35.719441] Call Trace: [ 35.719805] [] dump_stack+0xc1/0x128 [ 35.720517] [] print_address_description+0x73/0x280 [ 35.721392] [] kasan_report+0x275/0x360 [ 35.722145] [] ? __lock_acquire+0x2eff/0x3640 [ 35.722952] [] __asan_report_load8_noabort+0x14/0x20 [ 35.723840] [] __lock_acquire+0x2eff/0x3640 [ 35.724626] [] ? __lock_acquire+0x629/0x3640 [ 35.725424] [] ? debug_check_no_locks_freed+0x2c0/0x2c0 [ 35.726355] [] ? debug_check_no_locks_freed+0x2c0/0x2c0 [ 35.727276] [] ? debug_check_no_locks_freed+0x2c0/0x2c0 [ 35.728211] [] ? mark_held_locks+0xaf/0x100 [ 35.729009] [] ? mutex_lock_nested+0x5e3/0x870 [ 35.729829] [] lock_acquire+0x12e/0x410 [ 35.730572] [] ? remove_wait_queue+0x14/0x40 [ 35.731379] [] _raw_spin_lock_irqsave+0x4e/0x70 [ 35.737664] [] ? remove_wait_queue+0x14/0x40 [ 35.743702] [] remove_wait_queue+0x14/0x40 [ 35.749577] [] ep_unregister_pollwait.isra.6+0xaf/0x240 [ 35.756557] [] ? ep_unregister_pollwait.isra.6+0x12a/0x240 [ 35.763796] [] ? ep_free+0x1b0/0x1b0 [ 35.769125] [] ep_free+0x96/0x1b0 [ 35.774197] [] ? ep_free+0x1b0/0x1b0 [ 35.779529] [] ep_eventpoll_release+0x44/0x60 [ 35.785640] [] __fput+0x28c/0x6e0 [ 35.790716] [] ____fput+0x15/0x20 [ 35.795785] [] task_work_run+0x115/0x190 [ 35.801462] [] do_exit+0x7e7/0x2a40 [ 35.806705] [] ? selinux_file_ioctl+0x355/0x530 [ 35.812988] [] ? release_task+0x1240/0x1240 [ 35.818928] [] ? SyS_epoll_create+0x190/0x190 [ 35.825039] [] ? entry_SYSCALL_64_fastpath+0x5/0xc6 [ 35.831676] [] do_group_exit+0x108/0x320 [ 35.837353] [] SyS_exit_group+0x1d/0x20 [ 35.842940] [] entry_SYSCALL_64_fastpath+0x23/0xc6 [ 35.849484] [ 35.851075] Allocated by task 3337: [ 35.854666] save_stack_trace+0x16/0x20 [ 35.858617] save_stack+0x43/0xd0 [ 35.862034] kasan_kmalloc+0xad/0xe0 [ 35.865718] kmem_cache_alloc_trace+0xfb/0x2a0 [ 35.870264] binder_get_thread+0x15d/0x750 [ 35.874464] binder_poll+0x4a/0x210 [ 35.878055] SyS_epoll_ctl+0x11d7/0x2190 [ 35.882082] entry_SYSCALL_64_fastpath+0x23/0xc6 [ 35.886805] [ 35.888401] Freed by task 3337: [ 35.891647] save_stack_trace+0x16/0x20 [ 35.895586] save_stack+0x43/0xd0 [ 35.899003] kasan_slab_free+0x72/0xc0 [ 35.902860] kfree+0x103/0x300 [ 35.906015] binder_thread_dec_tmpref+0x1cc/0x240 [ 35.910823] binder_thread_release+0x27d/0x540 [ 35.915368] binder_ioctl+0x9c0/0x11b0 [ 35.919220] do_vfs_ioctl+0x1aa/0x1140 [ 35.923076] SyS_ioctl+0x8f/0xc0 [ 35.926404] entry_SYSCALL_64_fastpath+0x23/0xc6 [ 35.931122] [ 35.932716] The buggy address belongs to the object at ffff8801cc6ad180 [ 35.932716] which belongs to the cache kmalloc-512 of size 512 [ 35.945342] The buggy address is located 184 bytes inside of [ 35.945342] 512-byte region [ffff8801cc6ad180, ffff8801cc6ad380) [ 35.957186] The buggy address belongs to the page: [ 35.962080] page:ffffea000731ab00 count:1 mapcount:0 mapping: (null) index:0x0 compound_mapcount: 0 [ 35.972237] flags: 0x8000000000004080(slab|head) [ 35.976963] page dumped because: kasan: bad access detected [ 35.982635] [ 35.984226] Memory state around the buggy address: [ 35.989119] ffff8801cc6ad100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 35.996443] ffff8801cc6ad180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 36.003768] >ffff8801cc6ad200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 36.011098] ^ [ 36.016271] ffff8801cc6ad280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 36.023595] ffff8801cc6ad300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 36.030916] ================================================================== [ 36.038237] Disabling lock debugging due to kernel taint [ 36.043651] Kernel panic - not syncing: panic_on_warn set ... [ 36.043651] [ 36.050984] CPU: 0 PID: 3337 Comm: syzkaller817846 Tainted: G B 4.9.72-gcb7518e #114 [ 36.059958] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 36.069280] ffff8801c88bf838 ffffffff81d922b9 ffffffff841955bf ffff8801c88bf910 [ 36.077227] 0000000000000000 ffff8801cc6ad238 ffff8801cc6ad238 ffff8801c88bf900 [ 36.085173] ffffffff8142d741 0000000041b58ab3 ffffffff84189000 ffffffff8142d585 [ 36.093116] Call Trace: [ 36.095671] [] dump_stack+0xc1/0x128 [ 36.101001] [] panic+0x1bc/0x3a8 [ 36.105981] [] ? percpu_up_read_preempt_enable.constprop.53+0xd7/0xd7 [ 36.114179] [] ? add_taint+0x40/0x50 [ 36.119508] [] kasan_end_report+0x50/0x50 [ 36.125271] [] kasan_report+0x167/0x360 [ 36.130864] [] ? __lock_acquire+0x2eff/0x3640 [ 36.136974] [] __asan_report_load8_noabort+0x14/0x20 [ 36.143693] [] __lock_acquire+0x2eff/0x3640 [ 36.149634] [] ? __lock_acquire+0x629/0x3640 [ 36.155661] [] ? debug_check_no_locks_freed+0x2c0/0x2c0 [ 36.162639] [] ? debug_check_no_locks_freed+0x2c0/0x2c0 [ 36.169619] [] ? debug_check_no_locks_freed+0x2c0/0x2c0 [ 36.176605] [] ? mark_held_locks+0xaf/0x100 [ 36.182549] [] ? mutex_lock_nested+0x5e3/0x870 [ 36.188744] [] lock_acquire+0x12e/0x410 [ 36.194334] [] ? remove_wait_queue+0x14/0x40 [ 36.200364] [] _raw_spin_lock_irqsave+0x4e/0x70 [ 36.206655] [] ? remove_wait_queue+0x14/0x40 [ 36.212676] [] remove_wait_queue+0x14/0x40 [ 36.218526] [] ep_unregister_pollwait.isra.6+0xaf/0x240 [ 36.225505] [] ? ep_unregister_pollwait.isra.6+0x12a/0x240 [ 36.232743] [] ? ep_free+0x1b0/0x1b0 [ 36.238070] [] ep_free+0x96/0x1b0 [ 36.243137] [] ? ep_free+0x1b0/0x1b0 [ 36.248466] [] ep_eventpoll_release+0x44/0x60 [ 36.254583] [] __fput+0x28c/0x6e0 [ 36.259650] [] ____fput+0x15/0x20 [ 36.264715] [] task_work_run+0x115/0x190 [ 36.270394] [] do_exit+0x7e7/0x2a40 [ 36.275643] [] ? selinux_file_ioctl+0x355/0x530 [ 36.281927] [] ? release_task+0x1240/0x1240 [ 36.287864] [] ? SyS_epoll_create+0x190/0x190 [ 36.293973] [] ? entry_SYSCALL_64_fastpath+0x5/0xc6 [ 36.300605] [] do_group_exit+0x108/0x320 [ 36.306280] [] SyS_exit_group+0x1d/0x20 [ 36.311869] [] entry_SYSCALL_64_fastpath+0x23/0xc6 [ 36.318799] Dumping ftrace buffer: [ 36.322306] (ftrace buffer empty) [ 36.325981] Kernel Offset: disabled [ 36.329571] Rebooting in 86400 seconds..