[....] Starting enhanced syslogd: rsyslogd[ 15.756824] audit: type=1400 audit(1519641267.529:5): avc: denied { syslog } for pid=4066 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 syzkaller login: [ 19.181796] audit: type=1400 audit(1519641270.954:6): avc: denied { map } for pid=4206 comm="bash" path="/bin/bash" dev="sda1" ino=1457 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 Warning: Permanently added '10.128.15.194' (ECDSA) to the list of known hosts. executing program [ 28.346593] audit: type=1400 audit(1519641280.119:7): avc: denied { map } for pid=4220 comm="syzkaller765492" path="/root/syzkaller765492231" dev="sda1" ino=16481 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:object_r:user_home_t:s0 tclass=file permissive=1 [ 28.349865] [ 28.372542] audit: type=1400 audit(1519641280.119:8): avc: denied { map } for pid=4220 comm="syzkaller765492" path="/dev/ashmem" dev="devtmpfs" ino=264 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=system_u:object_r:device_t:s0 tclass=chr_file permissive=1 [ 28.374096] ====================================================== [ 28.374099] WARNING: possible circular locking dependency detected [ 28.374103] 4.16.0-rc2+ #329 Not tainted [ 28.374105] ------------------------------------------------------ [ 28.374108] syzkaller765492/4220 is trying to acquire lock: [ 28.374110] (&mm->mmap_sem){++++}, at: [<00000000146483fb>] __might_fault+0xe0/0x1d0 [ 28.435224] [ 28.435224] but task is already holding lock: [ 28.441160] (ashmem_mutex){+.+.}, at: [<00000000a46bc7ab>] ashmem_ioctl+0x3db/0x11b0 [ 28.449105] [ 28.449105] which lock already depends on the new lock. [ 28.449105] [ 28.457387] [ 28.457387] the existing dependency chain (in reverse order) is: [ 28.464973] [ 28.464973] -> #1 (ashmem_mutex){+.+.}: [ 28.470411] __mutex_lock+0x16f/0x1a80 [ 28.474790] mutex_lock_nested+0x16/0x20 [ 28.479340] ashmem_mmap+0x53/0x410 [ 28.483459] mmap_region+0xa99/0x15a0 [ 28.487750] do_mmap+0x6c0/0xe00 [ 28.491608] vm_mmap_pgoff+0x1de/0x280 [ 28.495992] SyS_mmap_pgoff+0x462/0x5f0 [ 28.500462] SyS_mmap+0x16/0x20 [ 28.504241] do_syscall_64+0x280/0x940 [ 28.508619] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 28.514293] [ 28.514293] -> #0 (&mm->mmap_sem){++++}: [ 28.519817] lock_acquire+0x1d5/0x580 [ 28.524109] __might_fault+0x13a/0x1d0 [ 28.528489] _copy_from_user+0x2c/0x110 [ 28.532959] ashmem_ioctl+0x438/0x11b0 [ 28.537342] do_vfs_ioctl+0x1b1/0x1520 [ 28.541722] SyS_ioctl+0x8f/0xc0 [ 28.545580] do_syscall_64+0x280/0x940 [ 28.549957] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 28.555633] [ 28.555633] other info that might help us debug this: [ 28.555633] [ 28.563743] Possible unsafe locking scenario: [ 28.563743] [ 28.569769] CPU0 CPU1 [ 28.574411] ---- ---- [ 28.579044] lock(ashmem_mutex); [ 28.582467] lock(&mm->mmap_sem); [ 28.588491] lock(ashmem_mutex); [ 28.594431] lock(&mm->mmap_sem); [ 28.597938] [ 28.597938] *** DEADLOCK *** [ 28.597938] [ 28.603965] 1 lock held by syzkaller765492/4220: [ 28.608687] #0: (ashmem_mutex){+.+.}, at: [<00000000a46bc7ab>] ashmem_ioctl+0x3db/0x11b0 [ 28.617065] [ 28.617065] stack backtrace: [ 28.621533] CPU: 1 PID: 4220 Comm: syzkaller765492 Not tainted 4.16.0-rc2+ #329 [ 28.628945] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 28.638266] Call Trace: [ 28.640827] dump_stack+0x194/0x24d [ 28.644425] ? arch_local_irq_restore+0x53/0x53 [ 28.649067] print_circular_bug.isra.38+0x2cd/0x2dc [ 28.654056] ? save_trace+0xe0/0x2b0 [ 28.657741] __lock_acquire+0x30a8/0x3e00 [ 28.661857] ? ashmem_ioctl+0x3db/0x11b0 [ 28.665888] ? debug_check_no_locks_freed+0x3c0/0x3c0 [ 28.671046] ? __might_sleep+0x95/0x190 [ 28.674999] ? ashmem_ioctl+0x3db/0x11b0 [ 28.679038] ? __mutex_lock+0x16f/0x1a80 [ 28.683067] ? ashmem_ioctl+0x3db/0x11b0 [ 28.687100] ? proc_nr_files+0x60/0x60 [ 28.690957] ? ashmem_ioctl+0x3db/0x11b0 [ 28.694990] ? find_held_lock+0x35/0x1d0 [ 28.699024] ? mutex_lock_io_nested+0x1900/0x1900 [ 28.703837] ? uprobe_mmap+0x15a/0xc90 [ 28.707693] ? lock_downgrade+0x980/0x980 [ 28.711808] ? __mutex_unlock_slowpath+0xe9/0xac0 [ 28.716622] ? find_held_lock+0x35/0x1d0 [ 28.720654] ? lock_downgrade+0x980/0x980 [ 28.724779] ? vma_set_page_prot+0x16b/0x230 [ 28.729166] lock_acquire+0x1d5/0x580 [ 28.732945] ? lock_acquire+0x1d5/0x580 [ 28.736890] ? __might_fault+0xe0/0x1d0 [ 28.740833] ? lock_release+0xa40/0xa40 [ 28.744776] ? trace_event_raw_event_sched_switch+0x810/0x810 [ 28.750628] ? __might_sleep+0x95/0x190 [ 28.754572] __might_fault+0x13a/0x1d0 [ 28.758427] ? __might_fault+0xe0/0x1d0 [ 28.762373] _copy_from_user+0x2c/0x110 [ 28.766341] ashmem_ioctl+0x438/0x11b0 [ 28.770200] ? ashmem_release+0x190/0x190 [ 28.774319] ? trace_event_raw_event_sched_switch+0x810/0x810 [ 28.780172] ? down_read_killable+0x180/0x180 [ 28.784648] ? rcu_note_context_switch+0x710/0x710 [ 28.789549] ? ashmem_release+0x190/0x190 [ 28.793669] do_vfs_ioctl+0x1b1/0x1520 [ 28.797528] ? ioctl_preallocate+0x2b0/0x2b0 [ 28.801908] ? selinux_capable+0x40/0x40 [ 28.805937] ? putname+0xf3/0x130 [ 28.809360] ? fput+0xd2/0x140 [ 28.812525] ? SyS_mmap_pgoff+0x243/0x5f0 [ 28.816647] ? security_file_ioctl+0x7d/0xb0 [ 28.821026] ? security_file_ioctl+0x89/0xb0 [ 28.825407] SyS_ioctl+0x8f/0xc0 [ 28.828743] ? do_vfs_ioctl+0x1520/0x1520 [ 28.832863] do_syscall_64+0x280/0x940 [ 28.836721] ? __do_page_fault+0xc90/0xc90 [ 28.840927] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 28.845650] ? syscall_return_slowpath+0x550/0x550 [ 28.850548] ? syscall_return_slowpath+0x2ac/0x550 [ 28.855449] ? prepare_exit_to_usermode+0x350/0x350 [ 28.860438] ? entry_SYSCALL_64_after_hwframe+0x52/0xb7 [ 28.865786] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 28.870603] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 28.875779] RIP: 0033:0x43fd19 [ 28.878952] RSP: 002b:00007ffce5ca8848 EFLAGS: 00000217 ORIG_RAX: 0000000000000010 [ 28.886638] RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 000000000043fd19 [ 28.893887] RDX: 0000000000000000 RSI: 0000000000007709 R