[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[?25l[?1c7[ ok 8[?25h[?0c. [ 29.549924] kauditd_printk_skb: 7 callbacks suppressed [ 29.549936] audit: type=1800 audit(1542119622.544:29): pid=5873 uid=0 auid=4294967295 ses=4294967295 subj=_ op=collect_data cause=failed(directio) comm="startpar" name="rc.local" dev="sda1" ino=2432 res=0 [ 29.574682] audit: type=1800 audit(1542119622.554:30): pid=5873 uid=0 auid=4294967295 ses=4294967295 subj=_ op=collect_data cause=failed(directio) comm="startpar" name="rmnologin" dev="sda1" ino=2423 res=0 Debian GNU/Linux 7 syzkaller ttyS0 Warning: Permanently added '10.128.0.111' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 53.134736] ================================================================== [ 53.142312] BUG: KASAN: null-ptr-deref in refcount_sub_and_test_checked+0x9d/0x310 [ 53.150007] Read of size 4 at addr 0000000000000020 by task syz-executor744/6028 [ 53.157522] [ 53.159145] CPU: 1 PID: 6028 Comm: syz-executor744 Not tainted 4.20.0-rc2+ #111 [ 53.166594] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 53.175931] Call Trace: [ 53.178537] dump_stack+0x244/0x39d [ 53.182297] ? dump_stack_print_info.cold.1+0x20/0x20 [ 53.187496] ? do_group_exit+0x177/0x440 [ 53.191545] ? __x64_sys_exit_group+0x3e/0x50 [ 53.196033] ? vprintk_func+0x85/0x181 [ 53.199907] kasan_report.cold.8+0x6d/0x309 [ 53.204215] ? refcount_sub_and_test_checked+0x9d/0x310 [ 53.209566] check_memory_region+0x13e/0x1b0 [ 53.213964] kasan_check_read+0x11/0x20 [ 53.217978] refcount_sub_and_test_checked+0x9d/0x310 [ 53.223162] ? lockdep_hardirqs_on+0x3bb/0x5b0 [ 53.227737] ? refcount_inc_not_zero_checked+0x2f0/0x2f0 [ 53.233177] ? vb2_vmalloc_put+0x5f/0x80 [ 53.237316] ? trace_hardirqs_off_caller+0x310/0x310 [ 53.242425] ? __kasan_slab_free+0x119/0x150 [ 53.246904] refcount_dec_and_test_checked+0x1a/0x20 [ 53.252004] vb2_vmalloc_put+0x19/0x80 [ 53.255888] __vb2_buf_mem_free+0x112/0x210 [ 53.260197] ? vb2_vmalloc_get_dmabuf+0x300/0x300 [ 53.265030] __vb2_queue_free+0x830/0xa30 [ 53.269177] ? trace_hardirqs_off_caller+0x310/0x310 [ 53.274273] ? __vb2_plane_dmabuf_put.isra.5+0x310/0x310 [ 53.279713] vb2_core_queue_release+0x62/0x80 [ 53.284206] _vb2_fop_release+0x1d2/0x2b0 [ 53.288343] vb2_fop_release+0x77/0xc0 [ 53.292225] vivid_fop_release+0x18e/0x440 [ 53.296450] ? vivid_remove+0x460/0x460 [ 53.300410] v4l2_release+0x224/0x3a0 [ 53.304198] ? dev_debug_store+0x140/0x140 [ 53.308421] __fput+0x385/0xa30 [ 53.311689] ? get_max_files+0x20/0x20 [ 53.315563] ? trace_hardirqs_on+0xbd/0x310 [ 53.319885] ? kasan_check_read+0x11/0x20 [ 53.324030] ? task_work_run+0x1af/0x2a0 [ 53.328081] ? trace_hardirqs_off_caller+0x310/0x310 [ 53.333179] ____fput+0x15/0x20 [ 53.336445] task_work_run+0x1e8/0x2a0 [ 53.340385] ? task_work_cancel+0x240/0x240 [ 53.344703] ? __sanitizer_cov_trace_const_cmp1+0x1a/0x20 [ 53.350240] ? switch_task_namespaces+0x9d/0xd0 [ 53.354907] do_exit+0x1ad6/0x26d0 [ 53.358437] ? mm_update_next_owner+0x990/0x990 [ 53.363223] ? kvfree+0x66/0x70 [ 53.366494] ? video_usercopy+0x79b/0x1760 [ 53.370730] ? v4l_s_fmt+0x990/0x990 [ 53.374442] ? v4l_enumstd+0x70/0x70 [ 53.378147] ? rcu_softirq_qs+0x20/0x20 [ 53.382138] ? is_bpf_text_address+0xd3/0x170 [ 53.386653] ? __kernel_text_address+0xd/0x40 [ 53.391137] ? unwind_get_return_address+0x61/0xa0 [ 53.396060] ? __save_stack_trace+0x8d/0xf0 [ 53.400373] ? smk_access+0x53b/0x700 [ 53.404201] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 53.409745] ? smack_log+0x423/0x590 [ 53.413453] ? smk_access_entry+0x310/0x310 [ 53.417772] ? trace_hardirqs_off+0xb8/0x310 [ 53.422190] ? smk_tskacc+0x3dd/0x520 [ 53.425991] ? video_usercopy+0x1760/0x1760 [ 53.430302] ? video_ioctl2+0x2c/0x33 [ 53.434439] ? v4l2_ioctl+0x15c/0x1b0 [ 53.438223] ? video_devdata+0xa0/0xa0 [ 53.442105] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 53.447650] ? do_vfs_ioctl+0x201/0x1790 [ 53.451704] ? rcu_lockdep_current_cpu_online+0x1a4/0x210 [ 53.457240] ? ioctl_preallocate+0x300/0x300 [ 53.461679] ? smk_curacc+0x7f/0xa0 [ 53.465301] ? smack_file_ioctl+0x210/0x3c0 [ 53.469903] ? fget_raw+0x20/0x20 [ 53.473347] ? smack_file_lock+0x2e0/0x2e0 [ 53.477570] ? rcu_read_lock_sched_held+0x14f/0x180 [ 53.482586] do_group_exit+0x177/0x440 [ 53.486544] ? trace_hardirqs_on+0xbd/0x310 [ 53.490862] ? __ia32_sys_exit+0x50/0x50 [ 53.494914] ? trace_hardirqs_off_caller+0x310/0x310 [ 53.500118] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 53.505928] ? ksys_ioctl+0x81/0xd0 [ 53.509677] __x64_sys_exit_group+0x3e/0x50 [ 53.514060] do_syscall_64+0x1b9/0x820 [ 53.517983] ? entry_SYSCALL_64_after_hwframe+0x3e/0xbe [ 53.523341] ? syscall_return_slowpath+0x5e0/0x5e0 [ 53.528270] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 53.533109] ? trace_hardirqs_on_caller+0x310/0x310 [ 53.538112] ? prepare_exit_to_usermode+0x3b0/0x3b0 [ 53.543122] ? prepare_exit_to_usermode+0x291/0x3b0 [ 53.548134] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 53.553009] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 53.558218] RIP: 0033:0x442c78 [ 53.561405] Code: Bad RIP value. [ 53.564753] RSP: 002b:00007fff2c9357e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 53.572453] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000442c78 [ 53.579724] RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000 [ 53.586980] RBP: 00000000004c2848 R08: 00000000000000e7 R09: ffffffffffffffd0 [ 53.594236] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 [ 53.601492] R13: 00000000006d4180 R14: 0000000000000000 R15: 0000000000000000 [ 53.608761] ================================================================== [ 53.616272] Disabling lock debugging due to kernel taint [ 53.622220] Kernel panic - not syncing: panic_on_warn set ... [ 53.628205] CPU: 1 PID: 6028 Comm: syz-executor744 Tainted: G B 4.20.0-rc2+ #111 [ 53.637079] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 53.646430] Call Trace: [ 53.649027] dump_stack+0x244/0x39d [ 53.652648] ? dump_stack_print_info.cold.1+0x20/0x20 [ 53.657899] panic+0x2ad/0x55c [ 53.661090] ? add_taint.cold.5+0x16/0x16 [ 53.665232] ? preempt_schedule+0x4d/0x60 [ 53.669472] ? ___preempt_schedule+0x16/0x18 [ 53.673875] ? trace_hardirqs_on+0xb4/0x310 [ 53.678297] kasan_end_report+0x47/0x4f [ 53.682257] kasan_report.cold.8+0x76/0x309 [ 53.686604] ? refcount_sub_and_test_checked+0x9d/0x310 [ 53.692070] check_memory_region+0x13e/0x1b0 [ 53.696468] kasan_check_read+0x11/0x20 [ 53.700437] refcount_sub_and_test_checked+0x9d/0x310 [ 53.705621] ? lockdep_hardirqs_on+0x3bb/0x5b0 [ 53.710198] ? refcount_inc_not_zero_checked+0x2f0/0x2f0 [ 53.715637] ? vb2_vmalloc_put+0x5f/0x80 [ 53.719693] ? trace_hardirqs_off_caller+0x310/0x310 [ 53.724852] ? __kasan_slab_free+0x119/0x150 [ 53.729251] refcount_dec_and_test_checked+0x1a/0x20 [ 53.734340] vb2_vmalloc_put+0x19/0x80 [ 53.738216] __vb2_buf_mem_free+0x112/0x210 [ 53.742522] ? vb2_vmalloc_get_dmabuf+0x300/0x300 [ 53.747357] __vb2_queue_free+0x830/0xa30 [ 53.751505] ? trace_hardirqs_off_caller+0x310/0x310 [ 53.756601] ? __vb2_plane_dmabuf_put.isra.5+0x310/0x310 [ 53.762050] vb2_core_queue_release+0x62/0x80 [ 53.766538] _vb2_fop_release+0x1d2/0x2b0 [ 53.770744] vb2_fop_release+0x77/0xc0 [ 53.774631] vivid_fop_release+0x18e/0x440 [ 53.778856] ? vivid_remove+0x460/0x460 [ 53.782819] v4l2_release+0x224/0x3a0 [ 53.786611] ? dev_debug_store+0x140/0x140 [ 53.790842] __fput+0x385/0xa30 [ 53.794132] ? get_max_files+0x20/0x20 [ 53.798012] ? trace_hardirqs_on+0xbd/0x310 [ 53.802325] ? kasan_check_read+0x11/0x20 [ 53.806459] ? task_work_run+0x1af/0x2a0 [ 53.810508] ? trace_hardirqs_off_caller+0x310/0x310 [ 53.815707] ____fput+0x15/0x20 [ 53.818981] task_work_run+0x1e8/0x2a0 [ 53.822860] ? task_work_cancel+0x240/0x240 [ 53.827251] ? __sanitizer_cov_trace_const_cmp1+0x1a/0x20 [ 53.832782] ? switch_task_namespaces+0x9d/0xd0 [ 53.837444] do_exit+0x1ad6/0x26d0 [ 53.840979] ? mm_update_next_owner+0x990/0x990 [ 53.845641] ? kvfree+0x66/0x70 [ 53.848906] ? video_usercopy+0x79b/0x1760 [ 53.853126] ? v4l_s_fmt+0x990/0x990 [ 53.856893] ? v4l_enumstd+0x70/0x70 [ 53.860598] ? rcu_softirq_qs+0x20/0x20 [ 53.864565] ? is_bpf_text_address+0xd3/0x170 [ 53.869149] ? __kernel_text_address+0xd/0x40 [ 53.873635] ? unwind_get_return_address+0x61/0xa0 [ 53.878548] ? __save_stack_trace+0x8d/0xf0 [ 53.882859] ? smk_access+0x53b/0x700 [ 53.886650] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 53.892371] ? smack_log+0x423/0x590 [ 53.896076] ? smk_access_entry+0x310/0x310 [ 53.900385] ? trace_hardirqs_off+0xb8/0x310 [ 53.904779] ? smk_tskacc+0x3dd/0x520 [ 53.908569] ? video_usercopy+0x1760/0x1760 [ 53.912994] ? video_ioctl2+0x2c/0x33 [ 53.916784] ? v4l2_ioctl+0x15c/0x1b0 [ 53.920690] ? video_devdata+0xa0/0xa0 [ 53.924652] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 53.930187] ? do_vfs_ioctl+0x201/0x1790 [ 53.934242] ? rcu_lockdep_current_cpu_online+0x1a4/0x210 [ 53.939764] ? ioctl_preallocate+0x300/0x300 [ 53.944157] ? smk_curacc+0x7f/0xa0 [ 53.947768] ? smack_file_ioctl+0x210/0x3c0 [ 53.952211] ? fget_raw+0x20/0x20 [ 53.955657] ? smack_file_lock+0x2e0/0x2e0 [ 53.959939] ? rcu_read_lock_sched_held+0x14f/0x180 [ 53.965066] do_group_exit+0x177/0x440 [ 53.968998] ? trace_hardirqs_on+0xbd/0x310 [ 53.973316] ? __ia32_sys_exit+0x50/0x50 [ 53.977455] ? trace_hardirqs_off_caller+0x310/0x310 [ 53.982650] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 53.988174] ? ksys_ioctl+0x81/0xd0 [ 53.991834] __x64_sys_exit_group+0x3e/0x50 [ 53.996152] do_syscall_64+0x1b9/0x820 [ 54.000028] ? entry_SYSCALL_64_after_hwframe+0x3e/0xbe [ 54.005377] ? syscall_return_slowpath+0x5e0/0x5e0 [ 54.010288] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 54.015118] ? trace_hardirqs_on_caller+0x310/0x310 [ 54.020125] ? prepare_exit_to_usermode+0x3b0/0x3b0 [ 54.025130] ? prepare_exit_to_usermode+0x291/0x3b0 [ 54.030133] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 54.034967] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 54.040207] RIP: 0033:0x442c78 [ 54.043398] Code: Bad RIP value. [ 54.046743] RSP: 002b:00007fff2c9357e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 54.054440] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000442c78 [ 54.061698] RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000 [ 54.068962] RBP: 00000000004c2848 R08: 00000000000000e7 R09: ffffffffffffffd0 [ 54.076215] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 [ 54.083472] R13: 00000000006d4180 R14: 0000000000000000 R15: 0000000000000000 [ 54.091669] Kernel Offset: disabled [ 54.095335] Rebooting in 86400 seconds..