[....] Starting enhanced syslogd: rsyslogd[ 15.096425] audit: type=1400 audit(1519379585.277:5): avc: denied { syslog } for pid=3877 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: [ 20.862197] audit: type=1400 audit(1519379591.043:6): avc: denied { map } for pid=4018 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 '10.128.0.55' (ECDSA) to the list of known hosts. executing program [ 27.318609] audit: type=1400 audit(1519379597.499:7): avc: denied { map } for pid=4032 comm="syzkaller850820" path="/root/syzkaller850820857" 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 [ 27.321892] [ 27.344554] audit: type=1400 audit(1519379597.499:8): avc: denied { map } for pid=4032 comm="syzkaller850820" path="/dev/ashmem" dev="devtmpfs" ino=114 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=system_u:object_r:device_t:s0 tclass=chr_file permissive=1 [ 27.346098] ====================================================== [ 27.346100] WARNING: possible circular locking dependency detected [ 27.346105] 4.16.0-rc2+ #235 Not tainted [ 27.346107] ------------------------------------------------------ [ 27.346113] syzkaller850820/4032 is trying to acquire lock: [ 27.399263] (&mm->mmap_sem){++++}, at: [<000000001c3246b6>] __might_fault+0xe0/0x1d0 [ 27.407214] [ 27.407214] but task is already holding lock: [ 27.413152] (ashmem_mutex){+.+.}, at: [<000000003ae45614>] ashmem_ioctl+0x3db/0x11b0 [ 27.421098] [ 27.421098] which lock already depends on the new lock. [ 27.421098] [ 27.429380] [ 27.429380] the existing dependency chain (in reverse order) is: [ 27.436968] [ 27.436968] -> #1 (ashmem_mutex){+.+.}: [ 27.442399] __mutex_lock+0x16f/0x1a80 [ 27.446780] mutex_lock_nested+0x16/0x20 [ 27.451331] ashmem_mmap+0x53/0x410 [ 27.455461] mmap_region+0xa99/0x15a0 [ 27.459748] do_mmap+0x6c0/0xe00 [ 27.463604] vm_mmap_pgoff+0x1de/0x280 [ 27.467981] SyS_mmap_pgoff+0x462/0x5f0 [ 27.472446] do_fast_syscall_32+0x3ec/0xf9f [ 27.477257] entry_SYSENTER_compat+0x70/0x7f [ 27.482152] [ 27.482152] -> #0 (&mm->mmap_sem){++++}: [ 27.487673] lock_acquire+0x1d5/0x580 [ 27.491967] __might_fault+0x13a/0x1d0 [ 27.496344] _copy_from_user+0x2c/0x110 [ 27.500806] ashmem_ioctl+0x438/0x11b0 [ 27.505183] compat_ashmem_ioctl+0x3e/0x50 [ 27.509907] compat_SyS_ioctl+0x151/0x2a30 [ 27.514634] do_fast_syscall_32+0x3ec/0xf9f [ 27.519446] entry_SYSENTER_compat+0x70/0x7f [ 27.524338] [ 27.524338] other info that might help us debug this: [ 27.524338] [ 27.532457] Possible unsafe locking scenario: [ 27.532457] [ 27.538480] CPU0 CPU1 [ 27.543122] ---- ---- [ 27.547754] lock(ashmem_mutex); [ 27.551176] lock(&mm->mmap_sem); [ 27.557202] lock(ashmem_mutex); [ 27.563140] lock(&mm->mmap_sem); [ 27.566647] [ 27.566647] *** DEADLOCK *** [ 27.566647] [ 27.572678] 1 lock held by syzkaller850820/4032: [ 27.577399] #0: (ashmem_mutex){+.+.}, at: [<000000003ae45614>] ashmem_ioctl+0x3db/0x11b0 [ 27.585783] [ 27.585783] stack backtrace: [ 27.590257] CPU: 1 PID: 4032 Comm: syzkaller850820 Not tainted 4.16.0-rc2+ #235 [ 27.597672] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 27.607004] Call Trace: [ 27.609578] dump_stack+0x194/0x24d [ 27.613189] ? arch_local_irq_restore+0x53/0x53 [ 27.617837] print_circular_bug.isra.38+0x2cd/0x2dc [ 27.622842] ? save_trace+0xe0/0x2b0 [ 27.626541] __lock_acquire+0x30a8/0x3e00 [ 27.630668] ? ashmem_ioctl+0x3db/0x11b0 [ 27.634719] ? debug_check_no_locks_freed+0x3c0/0x3c0 [ 27.639889] ? __might_sleep+0x95/0x190 [ 27.643833] ? ashmem_ioctl+0x3db/0x11b0 [ 27.647862] ? __mutex_lock+0x16f/0x1a80 [ 27.651892] ? ashmem_ioctl+0x3db/0x11b0 [ 27.655924] ? ashmem_ioctl+0x3db/0x11b0 [ 27.659956] ? lock_downgrade+0x980/0x980 [ 27.664075] ? mutex_lock_io_nested+0x1900/0x1900 [ 27.668886] ? lock_release+0xa40/0xa40 [ 27.672828] ? vma_wants_writenotify+0x51/0x3b0 [ 27.677467] ? vma_set_page_prot+0x16b/0x230 [ 27.681847] ? avc_ss_reset+0x110/0x110 [ 27.685793] lock_acquire+0x1d5/0x580 [ 27.689562] ? lock_acquire+0x1d5/0x580 [ 27.693506] ? __might_fault+0xe0/0x1d0 [ 27.697451] ? userfaultfd_unmap_complete+0x327/0x510 [ 27.702611] ? lock_release+0xa40/0xa40 [ 27.706558] ? trace_event_raw_event_sched_switch+0x810/0x810 [ 27.712411] ? __might_sleep+0x95/0x190 [ 27.716357] __might_fault+0x13a/0x1d0 [ 27.720213] ? __might_fault+0xe0/0x1d0 [ 27.724158] _copy_from_user+0x2c/0x110 [ 27.728101] ashmem_ioctl+0x438/0x11b0 [ 27.731960] ? selinux_file_ioctl+0x444/0x690 [ 27.736422] ? __fget_light+0x2b2/0x3c0 [ 27.740364] ? ashmem_release+0x190/0x190 [ 27.744486] ? kmem_cache_free+0x258/0x2a0 [ 27.748691] compat_ashmem_ioctl+0x3e/0x50 [ 27.752897] compat_SyS_ioctl+0x151/0x2a30 [ 27.757100] ? do_fast_syscall_32+0x156/0xf9f [ 27.761566] ? ashmem_ioctl+0x11b0/0x11b0 [ 27.765683] ? do_ioctl+0x60/0x60 [ 27.769105] do_fast_syscall_32+0x3ec/0xf9f [ 27.773400] ? do_int80_syscall_32+0x9c0/0x9c0 [ 27.777954] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 27.782683] ? syscall_return_slowpath+0x550/0x550 [ 27.787585] ? syscall_return_slowpath+0x2ac/0x550 [ 27.792485] ? prepare_exit_to_usermode+0x350/0x350 [ 27.797473] ? sysret32_from_system_call+0x5/0x3c [ 27.802286] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 27.807098] entry_SYSENTER_compat+0x70/0x7f [ 27.811477] RIP: 0023:0xf7f3fc99 [ 27.814808] RSP: 002b:00000000ffce57bc EFLAGS: 00000286 ORIG_RAX: