[....] Starting enhanced syslogd: rsyslogd[ 13.325241] audit: type=1400 audit(1515664692.998:4): avc: denied { syslog } for pid=3178 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 '10.128.15.220' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 20.764850] ================================================================== [ 20.772246] BUG: KASAN: use-after-free in __lock_acquire+0x2eff/0x3640 [ 20.778888] Read of size 8 at addr ffff8801c93abc38 by task syzkaller013896/3326 [ 20.786387] [ 20.787985] CPU: 1 PID: 3326 Comm: syzkaller013896 Not tainted 4.9.76-g9154940 #10 [ 20.795656] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 20.804981] ffff8801c8f278e0 ffffffff81d93149 ffffea000724ea80 ffff8801c93abc38 [ 20.812961] 0000000000000000 ffff8801c93abc38 ffff8801c93abc38 ffff8801c8f27918 [ 20.820915] ffffffff8153cb43 ffff8801c93abc38 0000000000000008 0000000000000000 [ 20.828879] Call Trace: [ 20.831434] [] dump_stack+0xc1/0x128 [ 20.836771] [] print_address_description+0x73/0x280 [ 20.843404] [] kasan_report+0x275/0x360 [ 20.849092] [] ? __lock_acquire+0x2eff/0x3640 [ 20.855203] [] __asan_report_load8_noabort+0x14/0x20 [ 20.861922] [] __lock_acquire+0x2eff/0x3640 [ 20.867862] [] ? __lock_acquire+0x629/0x3640 [ 20.873891] [] ? debug_check_no_locks_freed+0x2c0/0x2c0 [ 20.880883] [] ? debug_check_no_locks_freed+0x2c0/0x2c0 [ 20.887867] [] ? debug_check_no_locks_freed+0x2c0/0x2c0 [ 20.894846] [] ? mark_held_locks+0xaf/0x100 [ 20.900797] [] ? mutex_lock_nested+0x5e3/0x870 [ 20.907002] [] lock_acquire+0x12e/0x410 [ 20.912603] [] ? remove_wait_queue+0x14/0x40 [ 20.918632] [] _raw_spin_lock_irqsave+0x4e/0x70 [ 20.924915] [] ? remove_wait_queue+0x14/0x40 [ 20.930941] [] remove_wait_queue+0x14/0x40 [ 20.936822] [] ep_unregister_pollwait.isra.6+0xaf/0x240 [ 20.943819] [] ? ep_unregister_pollwait.isra.6+0x12a/0x240 [ 20.951063] [] ? ep_free+0x1b0/0x1b0 [ 20.956399] [] ep_free+0x96/0x1b0 [ 20.961489] [] ? ep_free+0x1b0/0x1b0 [ 20.966819] [] ep_eventpoll_release+0x44/0x60 [ 20.972943] [] __fput+0x28c/0x6e0 [ 20.978015] [] ____fput+0x15/0x20 [ 20.983084] [] task_work_run+0x115/0x190 [ 20.988761] [] do_exit+0x7e7/0x2a40 [ 20.994003] [] ? selinux_file_ioctl+0x355/0x530 [ 21.000289] [] ? release_task+0x1240/0x1240 [ 21.006235] [] ? SyS_epoll_create+0x190/0x190 [ 21.012348] [] ? entry_SYSCALL_64_fastpath+0x5/0xe2 [ 21.018980] [] do_group_exit+0x108/0x320 [ 21.024666] [] SyS_exit_group+0x1d/0x20 [ 21.030261] [] entry_SYSCALL_64_fastpath+0x23/0xe2 [ 21.036805] [ 21.038403] Allocated by task 3326: [ 21.041996] save_stack_trace+0x16/0x20 [ 21.045935] save_stack+0x43/0xd0 [ 21.049355] kasan_kmalloc+0xad/0xe0 [ 21.053040] kmem_cache_alloc_trace+0xfb/0x2a0 [ 21.057595] binder_get_thread+0x15d/0x750 [ 21.061793] binder_poll+0x4a/0x210 [ 21.065384] SyS_epoll_ctl+0x11d7/0x2190 [ 21.069411] entry_SYSCALL_64_fastpath+0x23/0xe2 [ 21.074129] [ 21.075721] Freed by task 3326: [ 21.078965] save_stack_trace+0x16/0x20 [ 21.082905] save_stack+0x43/0xd0 [ 21.086321] kasan_slab_free+0x72/0xc0 [ 21.090183] kfree+0x103/0x300 [ 21.093348] binder_thread_dec_tmpref+0x1cc/0x240 [ 21.098157] binder_thread_release+0x27d/0x540 [ 21.102712] binder_ioctl+0x9c0/0x11b0 [ 21.106570] do_vfs_ioctl+0x1aa/0x1140 [ 21.110423] SyS_ioctl+0x8f/0xc0 [ 21.113761] entry_SYSCALL_64_fastpath+0x23/0xe2 [ 21.118485] [ 21.120079] The buggy address belongs to the object at ffff8801c93abb80 [ 21.120079] which belongs to the cache kmalloc-512 of size 512 [ 21.132714] The buggy address is located 184 bytes inside of [ 21.132714] 512-byte region [ffff8801c93abb80, ffff8801c93abd80) [ 21.144555] The buggy address belongs to the page: [ 21.149465] page:ffffea000724ea80 count:1 mapcount:0 mapping: (null) index:0x0 compound_mapcount: 0 [ 21.159627] flags: 0x8000000000004080(slab|head) [ 21.164351] page dumped because: kasan: bad access detected [ 21.170024] [ 21.171615] Memory state around the buggy address: [ 21.176509] ffff8801c93abb00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 21.183835] ffff8801c93abb80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 21.191164] >ffff8801c93abc00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 21.198498] ^ [ 21.203650] ffff8801c93abc80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 21.210975] ffff8801c93abd00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 21.218295] ================================================================== [ 21.225615] Disabling lock debugging due to kernel taint [ 21.231026] Kernel panic - not syncing: panic_on_warn set ... [ 21.231026] [ 21.238362] CPU: 1 PID: 3326 Comm: syzkaller013896 Tainted: G B 4.9.76-g9154940 #10 [ 21.247248] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 21.256569] ffff8801c8f27838 ffffffff81d93149 ffffffff84195c17 ffff8801c8f27910 [ 21.264529] 0000000000000000 ffff8801c93abc38 ffff8801c93abc38 ffff8801c8f27900 [ 21.272497] ffffffff8142e371 0000000041b58ab3 ffffffff84189678 ffffffff8142e1b5 [ 21.280464] Call Trace: [ 21.283021] [] dump_stack+0xc1/0x128 [ 21.288350] [] panic+0x1bc/0x3a8 [ 21.293331] [] ? percpu_up_read_preempt_enable.constprop.53+0xd7/0xd7 [ 21.301525] [] ? add_taint+0x40/0x50 [ 21.306862] [] kasan_end_report+0x50/0x50 [ 21.312629] [] kasan_report+0x167/0x360 [ 21.318219] [] ? __lock_acquire+0x2eff/0x3640 [ 21.324331] [] __asan_report_load8_noabort+0x14/0x20 [ 21.331057] [] __lock_acquire+0x2eff/0x3640 [ 21.336997] [] ? __lock_acquire+0x629/0x3640 [ 21.343024] [] ? debug_check_no_locks_freed+0x2c0/0x2c0 [ 21.350008] [] ? debug_check_no_locks_freed+0x2c0/0x2c0 [ 21.356987] [] ? debug_check_no_locks_freed+0x2c0/0x2c0 [ 21.363972] [] ? mark_held_locks+0xaf/0x100 [ 21.369913] [] ? mutex_lock_nested+0x5e3/0x870 [ 21.376116] [] lock_acquire+0x12e/0x410 [ 21.381709] [] ? remove_wait_queue+0x14/0x40 [ 21.387736] [] _raw_spin_lock_irqsave+0x4e/0x70 [ 21.394020] [] ? remove_wait_queue+0x14/0x40 [ 21.400043] [] remove_wait_queue+0x14/0x40 [ 21.405895] [] ep_unregister_pollwait.isra.6+0xaf/0x240 [ 21.412880] [] ? ep_unregister_pollwait.isra.6+0x12a/0x240 [ 21.420120] [] ? ep_free+0x1b0/0x1b0 [ 21.425454] [] ep_free+0x96/0x1b0 [ 21.430561] [] ? ep_free+0x1b0/0x1b0 [ 21.435904] [] ep_eventpoll_release+0x44/0x60 [ 21.442028] [] __fput+0x28c/0x6e0 [ 21.447112] [] ____fput+0x15/0x20 [ 21.452179] [] task_work_run+0x115/0x190 [ 21.457857] [] do_exit+0x7e7/0x2a40 [ 21.463106] [] ? selinux_file_ioctl+0x355/0x530 [ 21.469391] [] ? release_task+0x1240/0x1240 [ 21.475335] [] ? SyS_epoll_create+0x190/0x190 [ 21.481446] [] ? entry_SYSCALL_64_fastpath+0x5/0xe2 [ 21.488084] [] do_group_exit+0x108/0x320 [ 21.493765] [] SyS_exit_group+0x1d/0x20 [ 21.499361] [] entry_SYSCALL_64_fastpath+0x23/0xe2 [ 21.506365] Dumping ftrace buffer: [ 21.509883] (ftrace buffer empty) [ 21.513560] Kernel Offset: disabled [ 21.517155] Rebooting in 86400 seconds..