[....] Starting enhanced syslogd: rsyslogd[ 17.790111] audit: type=1400 audit(1519637915.104:5): avc: denied { syslog } for pid=4119 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: [ 23.077525] audit: type=1400 audit(1519637920.392:6): avc: denied { map } for pid=4259 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 '10.128.0.8' (ECDSA) to the list of known hosts. executing program [ 29.396806] audit: type=1400 audit(1519637926.711:7): avc: denied { map } for pid=4273 comm="syzkaller092219" path="/root/syzkaller092219473" 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 [ 29.400526] [ 29.422751] audit: type=1400 audit(1519637926.711:8): avc: denied { map } for pid=4273 comm="syzkaller092219" path="/dev/ashmem" dev="devtmpfs" ino=1165 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=system_u:object_r:device_t:s0 tclass=chr_file permissive=1 [ 29.424294] ====================================================== [ 29.424296] WARNING: possible circular locking dependency detected [ 29.424301] 4.16.0-rc2+ #239 Not tainted [ 29.424303] ------------------------------------------------------ [ 29.424306] syzkaller092219/4273 is trying to acquire lock: [ 29.424308] (&mm->mmap_sem){++++}, at: [<00000000bc197c3e>] __might_fault+0xe0/0x1d0 [ 29.485526] [ 29.485526] but task is already holding lock: [ 29.491469] (ashmem_mutex){+.+.}, at: [<0000000025b2a1db>] ashmem_ioctl+0x3db/0x11b0 [ 29.499417] [ 29.499417] which lock already depends on the new lock. [ 29.499417] [ 29.507699] [ 29.507699] the existing dependency chain (in reverse order) is: [ 29.515294] [ 29.515294] -> #1 (ashmem_mutex){+.+.}: [ 29.520733] __mutex_lock+0x16f/0x1a80 [ 29.525112] mutex_lock_nested+0x16/0x20 [ 29.529666] ashmem_mmap+0x53/0x410 [ 29.533786] mmap_region+0xa99/0x15a0 [ 29.538075] do_mmap+0x6c0/0xe00 [ 29.541931] vm_mmap_pgoff+0x1de/0x280 [ 29.546308] SyS_mmap_pgoff+0x462/0x5f0 [ 29.550780] do_fast_syscall_32+0x3ec/0xf9f [ 29.555598] entry_SYSENTER_compat+0x70/0x7f [ 29.560499] [ 29.560499] -> #0 (&mm->mmap_sem){++++}: [ 29.566033] lock_acquire+0x1d5/0x580 [ 29.570330] __might_fault+0x13a/0x1d0 [ 29.574713] _copy_from_user+0x2c/0x110 [ 29.579177] ashmem_ioctl+0x438/0x11b0 [ 29.583553] compat_ashmem_ioctl+0x3e/0x50 [ 29.588280] compat_SyS_ioctl+0x151/0x2a30 [ 29.593010] do_fast_syscall_32+0x3ec/0xf9f [ 29.597932] entry_SYSENTER_compat+0x70/0x7f [ 29.602829] [ 29.602829] other info that might help us debug this: [ 29.602829] [ 29.610951] Possible unsafe locking scenario: [ 29.610951] [ 29.616977] CPU0 CPU1 [ 29.621611] ---- ---- [ 29.626243] lock(ashmem_mutex); [ 29.629668] lock(&mm->mmap_sem); [ 29.635696] lock(ashmem_mutex); [ 29.641637] lock(&mm->mmap_sem); [ 29.645145] [ 29.645145] *** DEADLOCK *** [ 29.645145] [ 29.651172] 1 lock held by syzkaller092219/4273: [ 29.655896] #0: (ashmem_mutex){+.+.}, at: [<0000000025b2a1db>] ashmem_ioctl+0x3db/0x11b0 [ 29.664287] [ 29.664287] stack backtrace: [ 29.668763] CPU: 1 PID: 4273 Comm: syzkaller092219 Not tainted 4.16.0-rc2+ #239 [ 29.676195] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 29.685521] Call Trace: [ 29.688092] dump_stack+0x194/0x24d [ 29.691691] ? arch_local_irq_restore+0x53/0x53 [ 29.696348] print_circular_bug.isra.38+0x2cd/0x2dc [ 29.701335] ? save_trace+0xe0/0x2b0 [ 29.705024] __lock_acquire+0x30a8/0x3e00 [ 29.709151] ? ashmem_ioctl+0x3db/0x11b0 [ 29.713186] ? debug_check_no_locks_freed+0x3c0/0x3c0 [ 29.718354] ? __might_sleep+0x95/0x190 [ 29.722299] ? ashmem_ioctl+0x3db/0x11b0 [ 29.726336] ? __mutex_lock+0x16f/0x1a80 [ 29.730370] ? ashmem_ioctl+0x3db/0x11b0 [ 29.734408] ? ashmem_ioctl+0x3db/0x11b0 [ 29.738452] ? lock_downgrade+0x980/0x980 [ 29.742574] ? mutex_lock_io_nested+0x1900/0x1900 [ 29.747386] ? lock_release+0xa40/0xa40 [ 29.751330] ? vma_wants_writenotify+0x51/0x3b0 [ 29.755969] ? vma_set_page_prot+0x16b/0x230 [ 29.760355] ? avc_ss_reset+0x110/0x110 [ 29.764302] lock_acquire+0x1d5/0x580 [ 29.768073] ? lock_acquire+0x1d5/0x580 [ 29.772026] ? __might_fault+0xe0/0x1d0 [ 29.775975] ? userfaultfd_unmap_complete+0x327/0x510 [ 29.781140] ? lock_release+0xa40/0xa40 [ 29.785088] ? trace_event_raw_event_sched_switch+0x810/0x810 [ 29.790950] ? __might_sleep+0x95/0x190 [ 29.794905] __might_fault+0x13a/0x1d0 [ 29.798765] ? __might_fault+0xe0/0x1d0 [ 29.802726] _copy_from_user+0x2c/0x110 [ 29.806672] ashmem_ioctl+0x438/0x11b0 [ 29.810533] ? selinux_file_ioctl+0x444/0x690 [ 29.814998] ? __fget_light+0x2b2/0x3c0 [ 29.818949] ? ashmem_release+0x190/0x190 [ 29.823070] ? kmem_cache_free+0x258/0x2a0 [ 29.827281] compat_ashmem_ioctl+0x3e/0x50 [ 29.831501] compat_SyS_ioctl+0x151/0x2a30 [ 29.835712] ? do_fast_syscall_32+0x156/0xf9f [ 29.840179] ? ashmem_ioctl+0x11b0/0x11b0 [ 29.844295] ? do_ioctl+0x60/0x60 [ 29.847719] do_fast_syscall_32+0x3ec/0xf9f [ 29.852034] ? do_int80_syscall_32+0x9c0/0x9c0 [ 29.856600] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 29.861337] ? syscall_return_slowpath+0x550/0x550 [ 29.866238] ? syscall_return_slowpath+0x2ac/0x550 [ 29.871139] ? prepare_exit_to_usermode+0x350/0x350 [ 29.876218] ? sysret32_from_system_call+0x5/0x3c [ 29.881041] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 29.885860] entry_SYSENTER_compat+0x70/0x7f [ 29.890240] RIP: 0023:0xf7efdc99 [ 29.893575] RSP: 002b:00000000ffb7d5dc EFLAGS: 00000282 ORIG_R