[....] Starting enhanced syslogd: rsyslogd[ 15.419550] audit: type=1400 audit(1520662446.625:5): avc: denied { syslog } for pid=4036 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: [ 19.376083] audit: type=1400 audit(1520662450.581:6): avc: denied { map } for pid=4177 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 '10.128.0.11' (ECDSA) to the list of known hosts. executing program [ 25.709794] audit: type=1400 audit(1520662456.915:7): avc: denied { map } for pid=4191 comm="syzkaller824925" path="/root/syzkaller824925012" 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 [ 25.713194] [ 25.735710] audit: type=1400 audit(1520662456.918:8): avc: denied { map } for pid=4191 comm="syzkaller824925" path="/dev/ashmem" dev="devtmpfs" ino=75 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=system_u:object_r:device_t:s0 tclass=chr_file permissive=1 [ 25.737282] ====================================================== [ 25.737284] WARNING: possible circular locking dependency detected [ 25.737288] 4.16.0-rc4+ #347 Not tainted [ 25.737290] ------------------------------------------------------ [ 25.737293] syzkaller824925/4191 is trying to acquire lock: [ 25.737295] (&mm->mmap_sem){++++}, at: [<00000000ee5423ca>] __might_fault+0xe0/0x1d0 [ 25.798287] [ 25.798287] but task is already holding lock: [ 25.804225] (ashmem_mutex){+.+.}, at: [<00000000dfe59b2b>] ashmem_ioctl+0x3db/0x11b0 [ 25.812178] [ 25.812178] which lock already depends on the new lock. [ 25.812178] [ 25.820458] [ 25.820458] the existing dependency chain (in reverse order) is: [ 25.828043] [ 25.828043] -> #1 (ashmem_mutex){+.+.}: [ 25.833471] __mutex_lock+0x16f/0x1a80 [ 25.837845] mutex_lock_nested+0x16/0x20 [ 25.842394] ashmem_mmap+0x53/0x410 [ 25.846507] mmap_region+0xa99/0x15a0 [ 25.850794] do_mmap+0x6c0/0xe00 [ 25.854645] vm_mmap_pgoff+0x1de/0x280 [ 25.859022] SyS_mmap_pgoff+0x462/0x5f0 [ 25.863485] SyS_mmap+0x16/0x20 [ 25.867257] do_syscall_64+0x281/0x940 [ 25.871631] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 25.877305] [ 25.877305] -> #0 (&mm->mmap_sem){++++}: [ 25.882816] lock_acquire+0x1d5/0x580 [ 25.887103] __might_fault+0x13a/0x1d0 [ 25.891480] _copy_from_user+0x2c/0x110 [ 25.895943] ashmem_ioctl+0x438/0x11b0 [ 25.900322] do_vfs_ioctl+0x1b1/0x1520 [ 25.904707] SyS_ioctl+0x8f/0xc0 [ 25.908563] do_syscall_64+0x281/0x940 [ 25.912938] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 25.918611] [ 25.918611] other info that might help us debug this: [ 25.918611] [ 25.926716] Possible unsafe locking scenario: [ 25.926716] [ 25.932741] CPU0 CPU1 [ 25.937372] ---- ---- [ 25.942004] lock(ashmem_mutex); [ 25.945428] lock(&mm->mmap_sem); [ 25.951449] lock(ashmem_mutex); [ 25.957383] lock(&mm->mmap_sem); [ 25.960886] [ 25.960886] *** DEADLOCK *** [ 25.960886] [ 25.966913] 1 lock held by syzkaller824925/4191: [ 25.971634] #0: (ashmem_mutex){+.+.}, at: [<00000000dfe59b2b>] ashmem_ioctl+0x3db/0x11b0 [ 25.980012] [ 25.980012] stack backtrace: [ 25.984478] CPU: 1 PID: 4191 Comm: syzkaller824925 Not tainted 4.16.0-rc4+ #347 [ 25.991890] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 26.001208] Call Trace: [ 26.003764] dump_stack+0x194/0x24d [ 26.007357] ? arch_local_irq_restore+0x53/0x53 [ 26.012019] print_circular_bug.isra.38+0x2cd/0x2dc [ 26.017004] ? save_trace+0xe0/0x2b0 [ 26.020693] __lock_acquire+0x30a8/0x3e00 [ 26.024810] ? ashmem_ioctl+0x3db/0x11b0 [ 26.028839] ? debug_check_no_locks_freed+0x3c0/0x3c0 [ 26.033999] ? __might_sleep+0x95/0x190 [ 26.037944] ? ashmem_ioctl+0x3db/0x11b0 [ 26.041972] ? __mutex_lock+0x16f/0x1a80 [ 26.046002] ? ashmem_ioctl+0x3db/0x11b0 [ 26.050037] ? proc_nr_files+0x60/0x60 [ 26.053892] ? ashmem_ioctl+0x3db/0x11b0 [ 26.057921] ? find_held_lock+0x35/0x1d0 [ 26.061948] ? mutex_lock_io_nested+0x1900/0x1900 [ 26.066759] ? uprobe_mmap+0x15a/0xc90 [ 26.070615] ? lock_downgrade+0x980/0x980 [ 26.074734] ? __mutex_unlock_slowpath+0xe9/0xac0 [ 26.079549] ? find_held_lock+0x35/0x1d0 [ 26.083579] ? lock_downgrade+0x980/0x980 [ 26.087699] ? vma_set_page_prot+0x16b/0x230 [ 26.092076] lock_acquire+0x1d5/0x580 [ 26.095856] ? lock_acquire+0x1d5/0x580 [ 26.099808] ? __might_fault+0xe0/0x1d0 [ 26.103757] ? lock_release+0xa40/0xa40 [ 26.107701] ? check_same_owner+0x320/0x320 [ 26.111992] ? __might_sleep+0x95/0x190 [ 26.115936] __might_fault+0x13a/0x1d0 [ 26.119790] ? __might_fault+0xe0/0x1d0 [ 26.123731] _copy_from_user+0x2c/0x110 [ 26.127674] ashmem_ioctl+0x438/0x11b0 [ 26.131529] ? ashmem_release+0x190/0x190 [ 26.135642] ? check_same_owner+0x320/0x320 [ 26.139932] ? down_read_killable+0x180/0x180 [ 26.144394] ? rcu_note_context_switch+0x710/0x710 [ 26.149289] ? ashmem_release+0x190/0x190 [ 26.153405] do_vfs_ioctl+0x1b1/0x1520 [ 26.157262] ? ioctl_preallocate+0x2b0/0x2b0 [ 26.161637] ? selinux_capable+0x40/0x40 [ 26.165665] ? putname+0xf3/0x130 [ 26.169103] ? fput+0xd2/0x140 [ 26.172262] ? SyS_mmap_pgoff+0x243/0x5f0 [ 26.176379] ? security_file_ioctl+0x7d/0xb0 [ 26.180756] ? security_file_ioctl+0x89/0xb0 [ 26.185131] SyS_ioctl+0x8f/0xc0 [ 26.188463] ? do_vfs_ioctl+0x1520/0x1520 [ 26.192579] do_syscall_64+0x281/0x940 [ 26.196433] ? trace_event_raw_event_sys_exit+0x260/0x260 [ 26.201936] ? syscall_return_slowpath+0x550/0x550 [ 26.206833] ? syscall_return_slowpath+0x2ac/0x550 [ 26.211730] ? entry_SYSCALL_64_after_hwframe+0x52/0xb7 [ 26.217068] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 26.221878] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 26.227036] RIP: 0033:0x43fd19 [ 26.230192] RSP: 002b:00007fffd09a40a8 EFLAGS: 00000217 ORIG_RAX: 0000000000000010 [ 26.237872] RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 000000000043fd19 [ 26.245108] RDX: 0000000000000000 RSI: 0000000000007709 RDI: 0000000000000003 [ 26.252343] RBP: 00000000006ca018 R08: 0000000000000000 R09: 0000000000000000 [ 26.259579] R10: 0000000000