[....] Starting enhanced syslogd: rsyslogd[ 13.128416] audit: type=1400 audit(1516248496.331:4): avc: denied { syslog } for pid=3176 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 '10.128.0.4' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 25.026365] ================================================================== [ 25.033745] BUG: KASAN: use-after-free in __lock_acquire+0x2eff/0x3640 [ 25.040381] Read of size 8 at addr ffff8801c8f24fb8 by task syzkaller973959/3333 [ 25.047877] [ 25.049473] CPU: 1 PID: 3333 Comm: syzkaller973959 Not tainted 4.9.77-g033d019 #24 [ 25.057143] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 25.066465] ffff8801c8c6f850 ffffffff81d941c9 ffffea000723c900 ffff8801c8f24fb8 [ 25.074443] 0000000000000000 ffff8801c8f24fb8 ffff8801c8f24fb8 ffff8801c8c6f888 [ 25.082409] ffffffff8153db93 ffff8801c8f24fb8 0000000000000008 0000000000000000 [ 25.090371] Call Trace: [ 25.092928] [] dump_stack+0xc1/0x128 [ 25.098267] [] print_address_description+0x73/0x280 [ 25.104902] [] kasan_report+0x275/0x360 [ 25.110496] [] ? __lock_acquire+0x2eff/0x3640 [ 25.116610] [] __asan_report_load8_noabort+0x14/0x20 [ 25.123338] [] __lock_acquire+0x2eff/0x3640 [ 25.129278] [] ? __lock_acquire+0x629/0x3640 [ 25.135303] [] ? debug_check_no_locks_freed+0x2c0/0x2c0 [ 25.142282] [] ? debug_check_no_locks_freed+0x2c0/0x2c0 [ 25.149261] [] ? __lock_is_held+0xa1/0xf0 [ 25.155023] [] lock_acquire+0x12e/0x410 [ 25.160612] [] ? remove_wait_queue+0x14/0x40 [ 25.166639] [] _raw_spin_lock_irqsave+0x4e/0x70 [ 25.172923] [] ? remove_wait_queue+0x14/0x40 [ 25.178947] [] remove_wait_queue+0x14/0x40 [ 25.184801] [] ep_unregister_pollwait.isra.6+0xaf/0x240 [ 25.191789] [] ? ep_unregister_pollwait.isra.6+0x12a/0x240 [ 25.199036] [] ep_remove+0x41/0x290 [ 25.204294] [] eventpoll_release_file+0xc5/0x140 [ 25.210666] [] __fput+0x5a8/0x6e0 [ 25.215739] [] ____fput+0x15/0x20 [ 25.220811] [] task_work_run+0x115/0x190 [ 25.226489] [] do_exit+0x7e7/0x2a40 [ 25.231734] [] ? __pmd_alloc+0x410/0x410 [ 25.237413] [] ? release_task+0x1240/0x1240 [ 25.243350] [] ? __do_page_fault+0x5ec/0xd40 [ 25.249375] [] ? up_read+0x1a/0x40 [ 25.254530] [] ? __do_page_fault+0x3bd/0xd40 [ 25.260552] [] do_group_exit+0x108/0x320 [ 25.266229] [] ? do_group_exit+0x320/0x320 [ 25.272080] [] SyS_exit_group+0x1d/0x20 [ 25.277674] [] do_fast_syscall_32+0x2f7/0x890 [ 25.283788] [] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 25.290424] [] entry_SYSENTER_compat+0x74/0x83 [ 25.296620] [ 25.298219] Allocated by task 3333: [ 25.301815] save_stack_trace+0x16/0x20 [ 25.305756] save_stack+0x43/0xd0 [ 25.309176] kasan_kmalloc+0xad/0xe0 [ 25.312860] kmem_cache_alloc_trace+0xfb/0x2a0 [ 25.317409] binder_get_thread+0x15d/0x750 [ 25.321620] binder_poll+0x4a/0x210 [ 25.325214] SyS_epoll_ctl+0x11d7/0x2190 [ 25.329245] do_fast_syscall_32+0x2f7/0x890 [ 25.333539] entry_SYSENTER_compat+0x74/0x83 [ 25.337911] [ 25.339505] Freed by task 3333: [ 25.342753] save_stack_trace+0x16/0x20 [ 25.346695] save_stack+0x43/0xd0 [ 25.350114] kasan_slab_free+0x72/0xc0 [ 25.353966] kfree+0x103/0x300 [ 25.357127] binder_thread_dec_tmpref+0x1cc/0x240 [ 25.361935] binder_thread_release+0x27d/0x540 [ 25.366482] binder_ioctl+0x9c0/0x11b0 [ 25.370336] compat_SyS_ioctl+0x15f/0x2050 [ 25.374539] do_fast_syscall_32+0x2f7/0x890 [ 25.378827] entry_SYSENTER_compat+0x74/0x83 [ 25.383202] [ 25.384805] The buggy address belongs to the object at ffff8801c8f24f00 [ 25.384805] which belongs to the cache kmalloc-512 of size 512 [ 25.397609] The buggy address is located 184 bytes inside of [ 25.397609] 512-byte region [ffff8801c8f24f00, ffff8801c8f25100) [ 25.409449] The buggy address belongs to the page: [ 25.414347] page:ffffea000723c900 count:1 mapcount:0 mapping: (null) index:0x0 compound_mapcount: 0 [ 25.424507] flags: 0x8000000000004080(slab|head) [ 25.429229] page dumped because: kasan: bad access detected [ 25.434902] [ 25.436494] Memory state around the buggy address: [ 25.441391] ffff8801c8f24e80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 25.448716] ffff8801c8f24f00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 25.456045] >ffff8801c8f24f80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 25.463368] ^ [ 25.468523] ffff8801c8f25000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 25.475848] ffff8801c8f25080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 25.483172] ================================================================== [ 25.490496] Disabling lock debugging due to kernel taint [ 25.495914] Kernel panic - not syncing: panic_on_warn set ... [ 25.495914] [ 25.503245] CPU: 1 PID: 3333 Comm: syzkaller973959 Tainted: G B 4.9.77-g033d019 #24 [ 25.512223] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 25.521546] ffff8801c8c6f7a8 ffffffff81d941c9 ffffffff841970ff ffff8801c8c6f880 [ 25.529522] 0000000000000000 ffff8801c8f24fb8 ffff8801c8f24fb8 ffff8801c8c6f870 [ 25.537487] ffffffff8142f3c1 0000000041b58ab3 ffffffff8418ab70 ffffffff8142f205 [ 25.545476] Call Trace: [ 25.548037] [] dump_stack+0xc1/0x128 [ 25.553372] [] panic+0x1bc/0x3a8 [ 25.558356] [] ? percpu_up_read_preempt_enable.constprop.53+0xd7/0xd7 [ 25.566558] [] ? add_taint+0x40/0x50 [ 25.571894] [] kasan_end_report+0x50/0x50 [ 25.577659] [] kasan_report+0x167/0x360 [ 25.583253] [] ? __lock_acquire+0x2eff/0x3640 [ 25.589366] [] __asan_report_load8_noabort+0x14/0x20 [ 25.596087] [] __lock_acquire+0x2eff/0x3640 [ 25.602025] [] ? __lock_acquire+0x629/0x3640 [ 25.608050] [] ? debug_check_no_locks_freed+0x2c0/0x2c0 [ 25.615030] [] ? debug_check_no_locks_freed+0x2c0/0x2c0 [ 25.622019] [] ? __lock_is_held+0xa1/0xf0 [ 25.627783] [] lock_acquire+0x12e/0x410 [ 25.633376] [] ? remove_wait_queue+0x14/0x40 [ 25.639402] [] _raw_spin_lock_irqsave+0x4e/0x70 [ 25.645688] [] ? remove_wait_queue+0x14/0x40 [ 25.651713] [] remove_wait_queue+0x14/0x40 [ 25.657567] [] ep_unregister_pollwait.isra.6+0xaf/0x240 [ 25.664548] [] ? ep_unregister_pollwait.isra.6+0x12a/0x240 [ 25.671790] [] ep_remove+0x41/0x290 [ 25.677034] [] eventpoll_release_file+0xc5/0x140 [ 25.683406] [] __fput+0x5a8/0x6e0 [ 25.688476] [] ____fput+0x15/0x20 [ 25.693546] [] task_work_run+0x115/0x190 [ 25.699225] [] do_exit+0x7e7/0x2a40 [ 25.704467] [] ? __pmd_alloc+0x410/0x410 [ 25.710146] [] ? release_task+0x1240/0x1240 [ 25.716085] [] ? __do_page_fault+0x5ec/0xd40 [ 25.722111] [] ? up_read+0x1a/0x40 [ 25.727267] [] ? __do_page_fault+0x3bd/0xd40 [ 25.733292] [] do_group_exit+0x108/0x320 [ 25.738970] [] ? do_group_exit+0x320/0x320 [ 25.744821] [] SyS_exit_group+0x1d/0x20 [ 25.750951] [] do_fast_syscall_32+0x2f7/0x890 [ 25.757074] [] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 25.763710] [] entry_SYSENTER_compat+0x74/0x83 [ 25.770793] Dumping ftrace buffer: [ 25.774305] (ftrace buffer empty) [ 25.777984] Kernel Offset: disabled [ 25.781576] Rebooting in 86400 seconds..