[....] Starting enhanced syslogd: rsyslogd[ 10.937974] audit: type=1400 audit(1516427582.333:4): 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[ ok 8[?25h[?0c. [....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. Starting mcstransd: [....] 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 '10.128.15.210' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 25.048867] ================================================================== [ 25.050018] BUG: KASAN: use-after-free in __lock_acquire+0x2eff/0x3640 [ 25.051071] Read of size 8 at addr ffff8801c9044ab8 by task syzkaller222473/3328 [ 25.052091] [ 25.052382] CPU: 0 PID: 3328 Comm: syzkaller222473 Not tainted 4.9.77-ge12a9c4 #27 [ 25.053495] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 25.054841] ffff8801c9f0f850 ffffffff81d941c9 ffffea0007241100 ffff8801c9044ab8 [ 25.056096] 0000000000000000 ffff8801c9044ab8 ffff8801c9044ab8 ffff8801c9f0f888 [ 25.057450] ffffffff8153db93 ffff8801c9044ab8 0000000000000008 0000000000000000 [ 25.058777] Call Trace: [ 25.059174] [] dump_stack+0xc1/0x128 [ 25.059908] [] print_address_description+0x73/0x280 [ 25.060926] [] kasan_report+0x275/0x360 [ 25.061721] [] ? __lock_acquire+0x2eff/0x3640 [ 25.062631] [] __asan_report_load8_noabort+0x14/0x20 [ 25.063656] [] __lock_acquire+0x2eff/0x3640 [ 25.064547] [] ? __lock_acquire+0x629/0x3640 [ 25.065389] [] ? debug_check_no_locks_freed+0x2c0/0x2c0 [ 25.066437] [] ? debug_check_no_locks_freed+0x2c0/0x2c0 [ 25.067444] [] ? __lock_is_held+0xa1/0xf0 [ 25.068242] [] lock_acquire+0x12e/0x410 [ 25.069044] [] ? remove_wait_queue+0x14/0x40 [ 25.075071] [] _raw_spin_lock_irqsave+0x4e/0x70 [ 25.081379] [] ? remove_wait_queue+0x14/0x40 [ 25.087415] [] remove_wait_queue+0x14/0x40 [ 25.093275] [] ep_unregister_pollwait.isra.6+0xaf/0x240 [ 25.100257] [] ? ep_unregister_pollwait.isra.6+0x12a/0x240 [ 25.107511] [] ep_remove+0x41/0x290 [ 25.112759] [] eventpoll_release_file+0xc5/0x140 [ 25.119143] [] __fput+0x5a8/0x6e0 [ 25.124216] [] ____fput+0x15/0x20 [ 25.129289] [] task_work_run+0x115/0x190 [ 25.134984] [] do_exit+0x7e7/0x2a40 [ 25.140233] [] ? __pmd_alloc+0x410/0x410 [ 25.145913] [] ? release_task+0x1240/0x1240 [ 25.151876] [] ? __do_page_fault+0x5ec/0xd40 [ 25.157909] [] ? up_read+0x1a/0x40 [ 25.163068] [] ? __do_page_fault+0x3bd/0xd40 [ 25.169098] [] do_group_exit+0x108/0x320 [ 25.174789] [] ? do_group_exit+0x320/0x320 [ 25.180646] [] SyS_exit_group+0x1d/0x20 [ 25.186246] [] do_fast_syscall_32+0x2f7/0x890 [ 25.192361] [] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 25.198997] [] entry_SYSENTER_compat+0x74/0x83 [ 25.205195] [ 25.206793] Allocated by task 3328: [ 25.210392] save_stack_trace+0x16/0x20 [ 25.214337] save_stack+0x43/0xd0 [ 25.217759] kasan_kmalloc+0xad/0xe0 [ 25.221447] kmem_cache_alloc_trace+0xfb/0x2a0 [ 25.226000] binder_get_thread+0x15d/0x750 [ 25.230215] binder_poll+0x4a/0x210 [ 25.233817] SyS_epoll_ctl+0x11d7/0x2190 [ 25.237849] do_fast_syscall_32+0x2f7/0x890 [ 25.242145] entry_SYSENTER_compat+0x74/0x83 [ 25.246519] [ 25.248116] Freed by task 3328: [ 25.251374] save_stack_trace+0x16/0x20 [ 25.255319] save_stack+0x43/0xd0 [ 25.258739] kasan_slab_free+0x72/0xc0 [ 25.262594] kfree+0x103/0x300 [ 25.265756] binder_thread_dec_tmpref+0x1cc/0x240 [ 25.270565] binder_thread_release+0x27d/0x540 [ 25.275117] binder_ioctl+0x9c0/0x11b0 [ 25.278978] compat_SyS_ioctl+0x15f/0x2050 [ 25.283183] do_fast_syscall_32+0x2f7/0x890 [ 25.287482] entry_SYSENTER_compat+0x74/0x83 [ 25.291858] [ 25.293456] The buggy address belongs to the object at ffff8801c9044a00 [ 25.293456] which belongs to the cache kmalloc-512 of size 512 [ 25.306081] The buggy address is located 184 bytes inside of [ 25.306081] 512-byte region [ffff8801c9044a00, ffff8801c9044c00) [ 25.317923] The buggy address belongs to the page: [ 25.322828] page:ffffea0007241100 count:1 mapcount:0 mapping: (null) index:0x0 compound_mapcount: 0 [ 25.333012] flags: 0x8000000000004080(slab|head) [ 25.337736] page dumped because: kasan: bad access detected [ 25.343414] [ 25.345009] Memory state around the buggy address: [ 25.349923] ffff8801c9044980: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 25.357255] ffff8801c9044a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 25.364591] >ffff8801c9044a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 25.371920] ^ [ 25.377078] ffff8801c9044b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 25.384416] ffff8801c9044b80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 25.391741] ================================================================== [ 25.399068] Disabling lock debugging due to kernel taint [ 25.404496] Kernel panic - not syncing: panic_on_warn set ... [ 25.404496] [ 25.411830] CPU: 0 PID: 3328 Comm: syzkaller222473 Tainted: G B 4.9.77-ge12a9c4 #27 [ 25.420723] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 25.430048] ffff8801c9f0f7a8 ffffffff81d941c9 ffffffff841970ff ffff8801c9f0f880 [ 25.438021] 0000000000000000 ffff8801c9044ab8 ffff8801c9044ab8 ffff8801c9f0f870 [ 25.445996] ffffffff8142f3c1 0000000041b58ab3 ffffffff8418ab70 ffffffff8142f205 [ 25.453977] Call Trace: [ 25.456544] [] dump_stack+0xc1/0x128 [ 25.461887] [] panic+0x1bc/0x3a8 [ 25.466873] [] ? percpu_up_read_preempt_enable.constprop.53+0xd7/0xd7 [ 25.475077] [] ? add_taint+0x40/0x50 [ 25.480411] [] kasan_end_report+0x50/0x50 [ 25.486182] [] kasan_report+0x167/0x360 [ 25.491780] [] ? __lock_acquire+0x2eff/0x3640 [ 25.497894] [] __asan_report_load8_noabort+0x14/0x20 [ 25.504620] [] __lock_acquire+0x2eff/0x3640 [ 25.510562] [] ? __lock_acquire+0x629/0x3640 [ 25.516590] [] ? debug_check_no_locks_freed+0x2c0/0x2c0 [ 25.523573] [] ? debug_check_no_locks_freed+0x2c0/0x2c0 [ 25.530559] [] ? __lock_is_held+0xa1/0xf0 [ 25.536326] [] lock_acquire+0x12e/0x410 [ 25.541935] [] ? remove_wait_queue+0x14/0x40 [ 25.547966] [] _raw_spin_lock_irqsave+0x4e/0x70 [ 25.554263] [] ? remove_wait_queue+0x14/0x40 [ 25.560290] [] remove_wait_queue+0x14/0x40 [ 25.566148] [] ep_unregister_pollwait.isra.6+0xaf/0x240 [ 25.573135] [] ? ep_unregister_pollwait.isra.6+0x12a/0x240 [ 25.580377] [] ep_remove+0x41/0x290 [ 25.585632] [] eventpoll_release_file+0xc5/0x140 [ 25.592007] [] __fput+0x5a8/0x6e0 [ 25.597089] [] ____fput+0x15/0x20 [ 25.602174] [] task_work_run+0x115/0x190 [ 25.607856] [] do_exit+0x7e7/0x2a40 [ 25.613102] [] ? __pmd_alloc+0x410/0x410 [ 25.618793] [] ? release_task+0x1240/0x1240 [ 25.624736] [] ? __do_page_fault+0x5ec/0xd40 [ 25.630765] [] ? up_read+0x1a/0x40 [ 25.635937] [] ? __do_page_fault+0x3bd/0xd40 [ 25.641966] [] do_group_exit+0x108/0x320 [ 25.647667] [] ? do_group_exit+0x320/0x320 [ 25.653522] [] SyS_exit_group+0x1d/0x20 [ 25.659125] [] do_fast_syscall_32+0x2f7/0x890 [ 25.665246] [] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 25.671884] [] entry_SYSENTER_compat+0x74/0x83 [ 25.678648] Dumping ftrace buffer: [ 25.682159] (ftrace buffer empty) [ 25.685839] Kernel Offset: disabled [ 25.689444] Rebooting in 86400 seconds..