[....] Starting enhanced syslogd: rsyslogd[ 17.714409] audit: type=1400 audit(1517813611.784:5): avc: denied { syslog } for pid=4006 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: [ 22.659506] audit: type=1400 audit(1517813616.729:6): avc: denied { map } for pid=4145 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 '10.128.0.57' (ECDSA) to the list of known hosts. [ 66.702513] audit: type=1400 audit(1517813660.772:7): avc: denied { map } for pid=4161 comm="syzkaller498395" path="/root/syzkaller498395859" 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 [ 66.706553] executing program [ 66.728466] audit: type=1400 audit(1517813660.776:8): avc: denied { map } for pid=4161 comm="syzkaller498395" path="/dev/ashmem" dev="devtmpfs" ino=1155 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=system_u:object_r:device_t:s0 tclass=chr_file permissive=1 [ 66.730030] ====================================================== [ 66.730031] WARNING: possible circular locking dependency detected [ 66.730035] 4.15.0+ #297 Not tainted [ 66.730036] ------------------------------------------------------ [ 66.730038] syzkaller498395/4161 is trying to acquire lock: [ 66.730043] (&sb->s_type->i_mutex_key#11){++++}, at: [<00000000e0fed4b4>] shmem_file_llseek+0xef/0x240 [ 66.792513] [ 66.792513] but task is already holding lock: [ 66.798451] (ashmem_mutex){+.+.}, at: [<00000000c309e187>] ashmem_llseek+0x56/0x1f0 [ 66.806319] [ 66.806319] which lock already depends on the new lock. [ 66.806319] [ 66.814604] [ 66.814604] the existing dependency chain (in reverse order) is: [ 66.822200] [ 66.822200] -> #2 (ashmem_mutex){+.+.}: [ 66.827642] __mutex_lock+0x16f/0x1a80 [ 66.832020] mutex_lock_nested+0x16/0x20 [ 66.836573] ashmem_mmap+0x53/0x410 [ 66.840689] mmap_region+0xa99/0x15a0 [ 66.844977] do_mmap+0x6c0/0xe00 [ 66.848831] vm_mmap_pgoff+0x1de/0x280 [ 66.853209] SyS_mmap_pgoff+0x462/0x5f0 [ 66.857675] SyS_mmap+0x16/0x20 [ 66.861451] do_syscall_64+0x282/0x940 [ 66.865830] entry_SYSCALL_64_after_hwframe+0x26/0x9b [ 66.871509] [ 66.871509] -> #1 (&mm->mmap_sem){++++}: [ 66.877022] __might_fault+0x13a/0x1d0 [ 66.881409] _copy_to_user+0x2c/0xc0 [ 66.885623] filldir+0x1a7/0x320 [ 66.889493] dcache_readdir+0x12d/0x5e0 [ 66.893978] iterate_dir+0x1ca/0x530 [ 66.898195] SyS_getdents+0x225/0x450 [ 66.902492] do_syscall_64+0x282/0x940 [ 66.906877] entry_SYSCALL_64_after_hwframe+0x26/0x9b [ 66.912574] [ 66.912574] -> #0 (&sb->s_type->i_mutex_key#11){++++}: [ 66.919314] lock_acquire+0x1d5/0x580 [ 66.923605] down_write+0x87/0x120 [ 66.927641] shmem_file_llseek+0xef/0x240 [ 66.932287] vfs_llseek+0xa2/0xd0 [ 66.936240] ashmem_llseek+0xe7/0x1f0 [ 66.940543] SyS_lseek+0xeb/0x170 [ 66.944491] do_syscall_64+0x282/0x940 [ 66.948879] entry_SYSCALL_64_after_hwframe+0x26/0x9b [ 66.954567] [ 66.954567] other info that might help us debug this: [ 66.954567] [ 66.962682] Chain exists of: [ 66.962682] &sb->s_type->i_mutex_key#11 --> &mm->mmap_sem --> ashmem_mutex [ 66.962682] [ 66.974190] Possible unsafe locking scenario: [ 66.974190] [ 66.980214] CPU0 CPU1 [ 66.984849] ---- ---- [ 66.989483] lock(ashmem_mutex); [ 66.992905] lock(&mm->mmap_sem); [ 66.998929] lock(ashmem_mutex); [ 67.004867] lock(&sb->s_type->i_mutex_key#11); [ 67.009603] [ 67.009603] *** DEADLOCK *** [ 67.009603] [ 67.015632] 1 lock held by syzkaller498395/4161: [ 67.020353] #0: (ashmem_mutex){+.+.}, at: [<00000000c309e187>] ashmem_llseek+0x56/0x1f0 [ 67.028664] [ 67.028664] stack backtrace: [ 67.033142] CPU: 1 PID: 4161 Comm: syzkaller498395 Not tainted 4.15.0+ #297 [ 67.040208] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 67.049533] Call Trace: [ 67.052093] dump_stack+0x194/0x257 [ 67.055690] ? arch_local_irq_restore+0x53/0x53 [ 67.060336] print_circular_bug.isra.38+0x2cd/0x2dc [ 67.065322] ? save_trace+0xe0/0x2b0 [ 67.069014] __lock_acquire+0x30a8/0x3e00 [ 67.073160] ? uprobe_mmap+0x15a/0xc90 [ 67.077035] ? debug_check_no_locks_freed+0x3c0/0x3c0 [ 67.082217] ? ashmem_llseek+0x56/0x1f0 [ 67.086166] ? lock_release+0xa40/0xa40 [ 67.090112] ? trace_event_raw_event_sched_switch+0x800/0x800 [ 67.095976] ? rcu_note_context_switch+0x710/0x710 [ 67.100884] ? __might_sleep+0x95/0x190 [ 67.104843] ? ashmem_llseek+0x56/0x1f0 [ 67.108790] ? __mutex_lock+0x16f/0x1a80 [ 67.112818] ? ashmem_llseek+0x56/0x1f0 [ 67.116766] ? mmap_region+0x52e/0x15a0 [ 67.120716] ? ashmem_llseek+0x56/0x1f0 [ 67.124661] ? mutex_lock_io_nested+0x1900/0x1900 [ 67.129479] ? lock_downgrade+0x980/0x980 [ 67.133705] ? userfaultfd_unmap_complete+0x327/0x510 [ 67.138875] lock_acquire+0x1d5/0x580 [ 67.142649] ? lock_acquire+0x1d5/0x580 [ 67.146603] ? shmem_file_llseek+0xef/0x240 [ 67.150899] ? lock_release+0xa40/0xa40 [ 67.154847] ? trace_event_raw_event_sched_switch+0x800/0x800 [ 67.160704] ? rcu_note_context_switch+0x710/0x710 [ 67.165631] ? __fget_light+0x2b2/0x3c0 [ 67.169578] ? __might_sleep+0x95/0x190 [ 67.173522] down_write+0x87/0x120 [ 67.177033] ? shmem_file_llseek+0xef/0x240 [ 67.181329] ? down_read+0x150/0x150 [ 67.185020] shmem_file_llseek+0xef/0x240 [ 67.189140] ? shmem_free_swap+0x80/0x80 [ 67.193173] vfs_llseek+0xa2/0xd0 [ 67.196599] ashmem_llseek+0xe7/0x1f0 [ 67.200369] ? ashmem_read_iter+0x230/0x230 [ 67.204662] SyS_lseek+0xeb/0x170 [ 67.208084] ? vfs_clone_file_range+0x6b0/0x6b0 [ 67.212728] do_syscall_64+0x282/0x940 [ 67.216588] ? __do_page_fault+0xc90/0xc90 [ 67.220795] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 67.225518] ? syscall_return_slowpath+0x550/0x550 [ 67.230419] ? syscall_return_slowpath+0x2ac/0x550 [ 67.235329] ? prepare_exit_to_usermode+0x350/0x350 [ 67.240317] ? entry_SYSCALL_64_after_hwframe+0x36/0x9b [ 67.245653] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 67.250466] entry_SYSCALL_64_after_hwframe+0x26/0