[....] Starting enhanced syslogd: rsyslogd[ 15.681472] audit: type=1400 audit(1518689752.266:5): avc: denied { syslog } for pid=4008 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 mcstransd: [....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] 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: [ 19.013807] audit: type=1400 audit(1518689755.598:6): avc: denied { map } for pid=4147 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 '10.128.15.209' (ECDSA) to the list of known hosts. executing program [ 25.306692] audit: type=1400 audit(1518689761.891:7): avc: denied { map } for pid=4161 comm="syzkaller841024" path="/root/syzkaller841024294" 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 [ 25.309990] [ 25.332649] audit: type=1400 audit(1518689761.891:8): avc: denied { map } for pid=4161 comm="syzkaller841024" path="/dev/ashmem" dev="devtmpfs" ino=1148 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=system_u:object_r:device_t:s0 tclass=chr_file permissive=1 [ 25.334192] ====================================================== [ 25.334194] WARNING: possible circular locking dependency detected [ 25.334198] 4.16.0-rc1+ #313 Not tainted [ 25.334200] ------------------------------------------------------ [ 25.334204] syzkaller841024/4161 is trying to acquire lock: [ 25.334205] (&sb->s_type->i_mutex_key#11){++++}, at: [<000000008a616a08>] shmem_file_llseek+0xef/0x240 [ 25.396946] [ 25.396946] but task is already holding lock: [ 25.402882] (ashmem_mutex){+.+.}, at: [<000000008e7ec4af>] ashmem_llseek+0x56/0x1f0 [ 25.410734] [ 25.410734] which lock already depends on the new lock. [ 25.410734] [ 25.419019] [ 25.419019] the existing dependency chain (in reverse order) is: [ 25.426957] [ 25.426957] -> #2 (ashmem_mutex){+.+.}: [ 25.432386] __mutex_lock+0x16f/0x1a80 [ 25.436762] mutex_lock_nested+0x16/0x20 [ 25.441313] ashmem_mmap+0x53/0x410 [ 25.445431] mmap_region+0xa99/0x15a0 [ 25.449721] do_mmap+0x6c0/0xe00 [ 25.453577] vm_mmap_pgoff+0x1de/0x280 [ 25.457953] SyS_mmap_pgoff+0x462/0x5f0 [ 25.462416] SyS_mmap+0x16/0x20 [ 25.466185] do_syscall_64+0x280/0x940 [ 25.470560] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 25.476235] [ 25.476235] -> #1 (&mm->mmap_sem){++++}: [ 25.481746] __might_fault+0x13a/0x1d0 [ 25.486123] _copy_to_user+0x2c/0xc0 [ 25.490325] filldir+0x1a7/0x320 [ 25.494182] dcache_readdir+0x12d/0x5e0 [ 25.498646] iterate_dir+0x1ca/0x530 [ 25.502847] SyS_getdents+0x225/0x450 [ 25.507135] do_syscall_64+0x280/0x940 [ 25.511511] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 25.517191] [ 25.517191] -> #0 (&sb->s_type->i_mutex_key#11){++++}: [ 25.523919] lock_acquire+0x1d5/0x580 [ 25.528205] down_write+0x87/0x120 [ 25.532238] shmem_file_llseek+0xef/0x240 [ 25.536873] vfs_llseek+0xa2/0xd0 [ 25.540821] ashmem_llseek+0xe7/0x1f0 [ 25.545115] SyS_lseek+0xeb/0x170 [ 25.549057] do_syscall_64+0x280/0x940 [ 25.553436] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 25.559111] [ 25.559111] other info that might help us debug this: [ 25.559111] [ 25.567218] Chain exists of: [ 25.567218] &sb->s_type->i_mutex_key#11 --> &mm->mmap_sem --> ashmem_mutex [ 25.567218] [ 25.578729] Possible unsafe locking scenario: [ 25.578729] [ 25.584863] CPU0 CPU1 [ 25.589516] ---- ---- [ 25.594165] lock(ashmem_mutex); [ 25.597591] lock(&mm->mmap_sem); [ 25.603618] lock(ashmem_mutex); [ 25.609555] lock(&sb->s_type->i_mutex_key#11); [ 25.614279] [ 25.614279] *** DEADLOCK *** [ 25.614279] [ 25.620321] 1 lock held by syzkaller841024/4161: [ 25.625040] #0: (ashmem_mutex){+.+.}, at: [<000000008e7ec4af>] ashmem_llseek+0x56/0x1f0 [ 25.633334] [ 25.633334] stack backtrace: [ 25.637798] CPU: 0 PID: 4161 Comm: syzkaller841024 Not tainted 4.16.0-rc1+ #313 [ 25.645210] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 25.654531] Call Trace: [ 25.657090] dump_stack+0x194/0x257 [ 25.660685] ? arch_local_irq_restore+0x53/0x53 [ 25.665325] print_circular_bug.isra.38+0x2cd/0x2dc [ 25.670311] ? save_trace+0xe0/0x2b0 [ 25.673994] __lock_acquire+0x30a8/0x3e00 [ 25.678116] ? uprobe_mmap+0x15a/0xc90 [ 25.681977] ? debug_check_no_locks_freed+0x3c0/0x3c0 [ 25.687134] ? ashmem_llseek+0x56/0x1f0 [ 25.691079] ? lock_release+0xa40/0xa40 [ 25.695026] ? trace_event_raw_event_sched_switch+0x810/0x810 [ 25.700885] ? rcu_note_context_switch+0x710/0x710 [ 25.705783] ? __might_sleep+0x95/0x190 [ 25.709724] ? ashmem_llseek+0x56/0x1f0 [ 25.713665] ? __mutex_lock+0x16f/0x1a80 [ 25.717691] ? ashmem_llseek+0x56/0x1f0 [ 25.721635] ? mmap_region+0x52e/0x15a0 [ 25.725576] ? ashmem_llseek+0x56/0x1f0 [ 25.729521] ? mutex_lock_io_nested+0x1900/0x1900 [ 25.734336] ? lock_downgrade+0x980/0x980 [ 25.738452] ? userfaultfd_unmap_complete+0x327/0x510 [ 25.743610] lock_acquire+0x1d5/0x580 [ 25.747382] ? lock_acquire+0x1d5/0x580 [ 25.751327] ? shmem_file_llseek+0xef/0x240 [ 25.755617] ? lock_release+0xa40/0xa40 [ 25.759561] ? trace_event_raw_event_sched_switch+0x810/0x810 [ 25.765416] ? rcu_note_context_switch+0x710/0x710 [ 25.770314] ? __fget_light+0x2b2/0x3c0 [ 25.774256] ? __might_sleep+0x95/0x190 [ 25.778203] down_write+0x87/0x120 [ 25.781713] ? shmem_file_llseek+0xef/0x240 [ 25.786002] ? down_read+0x150/0x150 [ 25.789691] shmem_file_llseek+0xef/0x240 [ 25.793809] ? shmem_free_swap+0x80/0x80 [ 25.797837] vfs_llseek+0xa2/0xd0 [ 25.801258] ashmem_llseek+0xe7/0x1f0 [ 25.805034] ? ashmem_read_iter+0x230/0x230 [ 25.809323] SyS_lseek+0xeb/0x170 [ 25.812743] ? vfs_clone_file_range+0x6b0/0x6b0 [ 25.817379] do_syscall_64+0x280/0x940 [ 25.821235] ? __do_page_fault+0xc90/0xc90 [ 25.825445] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 25.830169] ? syscall_return_slowpath+0x550/0x550 [ 25.835065] ? syscall_return_slowpath+0x2ac/0x550 [ 25.839962] ? prepare_exit_to_usermode+0x350/0x350 [ 25.844946] ? entry_SYSCALL_64_after_hwframe+0x52/0xb7 [ 25.850282] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 25.855093] entry_SYSCALL_64_after_hwframe+