[....] Starting enhanced syslogd: rsyslogd[ 11.349096] audit: type=1400 audit(1515665371.759:4): avc: denied { syslog } for pid=3177 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 mcstransd: [....] Starting periodic command scheduler: cron[?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c. [....] 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 '10.128.0.6' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 19.470803] ================================================================== [ 19.471852] BUG: KASAN: use-after-free in __lock_acquire+0x2eff/0x3640 [ 19.472745] Read of size 8 at addr ffff8801c96139b8 by task syzkaller313932/3325 [ 19.473729] [ 19.473963] CPU: 0 PID: 3325 Comm: syzkaller313932 Not tainted 4.9.76-g9154940 #10 [ 19.474971] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 19.476200] ffff8801c9ec78e0 ffffffff81d93149 ffffea0007258480 ffff8801c96139b8 [ 19.477370] 0000000000000000 ffff8801c96139b8 ffff8801c96139b8 ffff8801c9ec7918 [ 19.478521] ffffffff8153cb43 ffff8801c96139b8 0000000000000008 0000000000000000 [ 19.479690] Call Trace: [ 19.480047] [] dump_stack+0xc1/0x128 [ 19.480756] [] print_address_description+0x73/0x280 [ 19.481643] [] kasan_report+0x275/0x360 [ 19.482391] [] ? __lock_acquire+0x2eff/0x3640 [ 19.483221] [] __asan_report_load8_noabort+0x14/0x20 [ 19.484107] [] __lock_acquire+0x2eff/0x3640 [ 19.484904] [] ? __lock_acquire+0x629/0x3640 [ 19.485718] [] ? debug_check_no_locks_freed+0x2c0/0x2c0 [ 19.486638] [] ? debug_check_no_locks_freed+0x2c0/0x2c0 [ 19.487569] [] ? debug_check_no_locks_freed+0x2c0/0x2c0 [ 19.488498] [] ? mark_held_locks+0xaf/0x100 [ 19.489287] [] ? mutex_lock_nested+0x5e3/0x870 [ 19.490167] [] lock_acquire+0x12e/0x410 [ 19.490944] [] ? remove_wait_queue+0x14/0x40 [ 19.496966] [] _raw_spin_lock_irqsave+0x4e/0x70 [ 19.503248] [] ? remove_wait_queue+0x14/0x40 [ 19.509270] [] remove_wait_queue+0x14/0x40 [ 19.515125] [] ep_unregister_pollwait.isra.6+0xaf/0x240 [ 19.522103] [] ? ep_unregister_pollwait.isra.6+0x12a/0x240 [ 19.529341] [] ? ep_free+0x1b0/0x1b0 [ 19.534669] [] ep_free+0x96/0x1b0 [ 19.539743] [] ? ep_free+0x1b0/0x1b0 [ 19.545079] [] ep_eventpoll_release+0x44/0x60 [ 19.551189] [] __fput+0x28c/0x6e0 [ 19.556258] [] ____fput+0x15/0x20 [ 19.562085] [] task_work_run+0x115/0x190 [ 19.567773] [] do_exit+0x7e7/0x2a40 [ 19.573015] [] ? selinux_file_ioctl+0x355/0x530 [ 19.580789] [] ? release_task+0x1240/0x1240 [ 19.588728] [] ? SyS_epoll_create+0x190/0x190 [ 19.594840] [] ? entry_SYSCALL_64_fastpath+0x5/0xe2 [ 19.601471] [] do_group_exit+0x108/0x320 [ 19.607149] [] SyS_exit_group+0x1d/0x20 [ 19.612740] [] entry_SYSCALL_64_fastpath+0x23/0xe2 [ 19.619281] [ 19.620873] Allocated by task 3325: [ 19.624467] save_stack_trace+0x16/0x20 [ 19.628405] save_stack+0x43/0xd0 [ 19.631822] kasan_kmalloc+0xad/0xe0 [ 19.635512] kmem_cache_alloc_trace+0xfb/0x2a0 [ 19.640059] binder_get_thread+0x15d/0x750 [ 19.644267] binder_poll+0x4a/0x210 [ 19.647858] SyS_epoll_ctl+0x11d7/0x2190 [ 19.651883] entry_SYSCALL_64_fastpath+0x23/0xe2 [ 19.656600] [ 19.658191] Freed by task 3325: [ 19.661435] save_stack_trace+0x16/0x20 [ 19.665378] save_stack+0x43/0xd0 [ 19.668796] kasan_slab_free+0x72/0xc0 [ 19.672644] kfree+0x103/0x300 [ 19.675804] binder_thread_dec_tmpref+0x1cc/0x240 [ 19.680621] binder_thread_release+0x27d/0x540 [ 19.685166] binder_ioctl+0x9c0/0x11b0 [ 19.689022] do_vfs_ioctl+0x1aa/0x1140 [ 19.692882] SyS_ioctl+0x8f/0xc0 [ 19.696212] entry_SYSCALL_64_fastpath+0x23/0xe2 [ 19.700930] [ 19.702531] The buggy address belongs to the object at ffff8801c9613900 [ 19.702531] which belongs to the cache kmalloc-512 of size 512 [ 19.717059] The buggy address is located 184 bytes inside of [ 19.717059] 512-byte region [ffff8801c9613900, ffff8801c9613b00) [ 19.728901] The buggy address belongs to the page: [ 19.733793] page:ffffea0007258480 count:1 mapcount:0 mapping: (null) index:0x0 compound_mapcount: 0 [ 19.743947] flags: 0x8000000000004080(slab|head) [ 19.748662] page dumped because: kasan: bad access detected [ 19.754335] [ 19.755927] Memory state around the buggy address: [ 19.760827] ffff8801c9613880: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 19.768150] ffff8801c9613900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 19.775473] >ffff8801c9613980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 19.782797] ^ [ 19.789348] ffff8801c9613a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 19.796943] ffff8801c9613a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 19.804263] ================================================================== [ 19.811584] Disabling lock debugging due to kernel taint [ 19.816997] Kernel panic - not syncing: panic_on_warn set ... [ 19.816997] [ 19.824324] CPU: 0 PID: 3325 Comm: syzkaller313932 Tainted: G B 4.9.76-g9154940 #10 [ 19.833207] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 19.842531] ffff8801c9ec7838 ffffffff81d93149 ffffffff84195c17 ffff8801c9ec7910 [ 19.850492] 0000000000000000 ffff8801c96139b8 ffff8801c96139b8 ffff8801c9ec7900 [ 19.858436] ffffffff8142e371 0000000041b58ab3 ffffffff84189678 ffffffff8142e1b5 [ 19.866376] Call Trace: [ 19.868929] [] dump_stack+0xc1/0x128 [ 19.874257] [] panic+0x1bc/0x3a8 [ 19.879239] [] ? percpu_up_read_preempt_enable.constprop.53+0xd7/0xd7 [ 19.887430] [] ? add_taint+0x40/0x50 [ 19.893887] [] kasan_end_report+0x50/0x50 [ 19.899648] [] kasan_report+0x167/0x360 [ 19.905237] [] ? __lock_acquire+0x2eff/0x3640 [ 19.912043] [] __asan_report_load8_noabort+0x14/0x20 [ 19.918760] [] __lock_acquire+0x2eff/0x3640 [ 19.924694] [] ? __lock_acquire+0x629/0x3640 [ 19.930720] [] ? debug_check_no_locks_freed+0x2c0/0x2c0 [ 19.937706] [] ? debug_check_no_locks_freed+0x2c0/0x2c0 [ 19.944691] [] ? debug_check_no_locks_freed+0x2c0/0x2c0 [ 19.951670] [] ? mark_held_locks+0xaf/0x100 [ 19.957610] [] ? mutex_lock_nested+0x5e3/0x870 [ 19.963804] [] lock_acquire+0x12e/0x410 [ 19.970086] [] ? remove_wait_queue+0x14/0x40 [ 19.976456] [] _raw_spin_lock_irqsave+0x4e/0x70 [ 19.982738] [] ? remove_wait_queue+0x14/0x40 [ 19.988761] [] remove_wait_queue+0x14/0x40 [ 19.994611] [] ep_unregister_pollwait.isra.6+0xaf/0x240 [ 20.001587] [] ? ep_unregister_pollwait.isra.6+0x12a/0x240 [ 20.008825] [] ? ep_free+0x1b0/0x1b0 [ 20.014152] [] ep_free+0x96/0x1b0 [ 20.019218] [] ? ep_free+0x1b0/0x1b0 [ 20.024545] [] ep_eventpoll_release+0x44/0x60 [ 20.030661] [] __fput+0x28c/0x6e0 [ 20.035728] [] ____fput+0x15/0x20 [ 20.040799] [] task_work_run+0x115/0x190 [ 20.046475] [] do_exit+0x7e7/0x2a40 [ 20.051717] [] ? selinux_file_ioctl+0x355/0x530 [ 20.057998] [] ? release_task+0x1240/0x1240 [ 20.063933] [] ? SyS_epoll_create+0x190/0x190 [ 20.070040] [] ? entry_SYSCALL_64_fastpath+0x5/0xe2 [ 20.076688] [] do_group_exit+0x108/0x320 [ 20.082362] [] SyS_exit_group+0x1d/0x20 [ 20.087951] [] entry_SYSCALL_64_fastpath+0x23/0xe2 [ 20.095242] Dumping ftrace buffer: [ 20.098749] (ftrace buffer empty) [ 20.103033] Kernel Offset: disabled [ 20.106971] Rebooting in 86400 seconds..