[....] Starting enhanced syslogd: rsyslogd[ 11.641975] audit: type=1400 audit(1515561113.309:5): avc: denied { syslog } for pid=3338 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: [ 16.796556] audit: type=1400 audit(1515561118.464:6): avc: denied { map } for pid=3477 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 '10.128.15.218' (ECDSA) to the list of known hosts. net.ipv6.conf.syz0.accept_dad = 0 net.ipv6.conf.syz0.router_solicitations = 0 [ 22.971617] audit: type=1400 audit(1515561124.639:7): avc: denied { map } for pid=3491 comm="syzkaller858611" path="/root/syzkaller858611223" 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 executing program [ 23.044697] [ 23.046333] ====================================================== [ 23.052052] audit: type=1400 audit(1515561124.711:8): avc: denied { map } for pid=3491 comm="syzkaller858611" 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 [ 23.077299] WARNING: possible circular locking dependency detected [ 23.083596] 4.15.0-rc7+ #255 Not tainted [ 23.087635] ------------------------------------------------------ [ 23.093920] syzkaller858611/3491 is trying to acquire lock: [ 23.099594] (&sb->s_type->i_mutex_key#11){++++}, at: [<000000000eab9618>] shmem_file_llseek+0xef/0x240 [ 23.109104] [ 23.109104] but task is already holding lock: [ 23.115034] (ashmem_mutex){+.+.}, at: [<000000007678cd50>] ashmem_llseek+0x56/0x1f0 [ 23.122886] [ 23.122886] which lock already depends on the new lock. [ 23.122886] [ 23.131161] [ 23.131161] the existing dependency chain (in reverse order) is: [ 23.138745] [ 23.138745] -> #2 (ashmem_mutex){+.+.}: [ 23.144170] __mutex_lock+0x16f/0x1a80 [ 23.148552] mutex_lock_nested+0x16/0x20 [ 23.153103] ashmem_mmap+0x53/0x410 [ 23.157227] mmap_region+0xa99/0x15a0 [ 23.161517] do_mmap+0x6c0/0xe00 [ 23.165373] vm_mmap_pgoff+0x1de/0x280 [ 23.169746] SyS_mmap_pgoff+0x462/0x5f0 [ 23.174218] SyS_mmap+0x16/0x20 [ 23.177988] entry_SYSCALL_64_fastpath+0x23/0x9a [ 23.183226] [ 23.183226] -> #1 (&mm->mmap_sem){++++}: [ 23.188734] __might_fault+0x13a/0x1d0 [ 23.193115] _copy_to_user+0x2c/0xc0 [ 23.197312] filldir+0x1a7/0x320 [ 23.201164] dcache_readdir+0x12d/0x5e0 [ 23.205622] iterate_dir+0x1ca/0x530 [ 23.209820] SyS_getdents+0x225/0x450 [ 23.214109] entry_SYSCALL_64_fastpath+0x23/0x9a [ 23.219345] [ 23.219345] -> #0 (&sb->s_type->i_mutex_key#11){++++}: [ 23.226069] lock_acquire+0x1d5/0x580 [ 23.230354] down_write+0x87/0x120 [ 23.234380] shmem_file_llseek+0xef/0x240 [ 23.239014] vfs_llseek+0xa2/0xd0 [ 23.242950] ashmem_llseek+0xe7/0x1f0 [ 23.247233] SyS_lseek+0xeb/0x170 [ 23.251173] entry_SYSCALL_64_fastpath+0x23/0x9a [ 23.256411] [ 23.256411] other info that might help us debug this: [ 23.256411] [ 23.264518] Chain exists of: [ 23.264518] &sb->s_type->i_mutex_key#11 --> &mm->mmap_sem --> ashmem_mutex [ 23.264518] [ 23.276019] Possible unsafe locking scenario: [ 23.276019] [ 23.282036] CPU0 CPU1 [ 23.286663] ---- ---- [ 23.291291] lock(ashmem_mutex); [ 23.294709] lock(&mm->mmap_sem); [ 23.300729] lock(ashmem_mutex); [ 23.306663] lock(&sb->s_type->i_mutex_key#11); [ 23.311381] [ 23.311381] *** DEADLOCK *** [ 23.311381] [ 23.317404] 1 lock held by syzkaller858611/3491: [ 23.322122] #0: (ashmem_mutex){+.+.}, at: [<000000007678cd50>] ashmem_llseek+0x56/0x1f0 [ 23.330407] [ 23.330407] stack backtrace: [ 23.334868] CPU: 1 PID: 3491 Comm: syzkaller858611 Not tainted 4.15.0-rc7+ #255 [ 23.342276] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 23.351591] Call Trace: [ 23.354148] dump_stack+0x194/0x257 [ 23.357737] ? arch_local_irq_restore+0x53/0x53 [ 23.362375] print_circular_bug.isra.37+0x2cd/0x2dc [ 23.367356] ? save_trace+0xe0/0x2b0 [ 23.371033] __lock_acquire+0x30a8/0x3e00 [ 23.375149] ? debug_check_no_locks_freed+0x3c0/0x3c0 [ 23.380301] ? ashmem_llseek+0x56/0x1f0 [ 23.384250] ? lock_release+0xa40/0xa40 [ 23.388193] ? trace_event_raw_event_sched_switch+0x800/0x800 [ 23.394042] ? rcu_note_context_switch+0x710/0x710 [ 23.398934] ? vma_wants_writenotify+0x3b0/0x3b0 [ 23.403651] ? __might_sleep+0x95/0x190 [ 23.407589] ? ashmem_llseek+0x56/0x1f0 [ 23.411527] ? __mutex_lock+0x16f/0x1a80 [ 23.415551] ? ashmem_llseek+0x56/0x1f0 [ 23.419494] ? mmap_region+0x52e/0x15a0 [ 23.423433] ? ashmem_llseek+0x56/0x1f0 [ 23.427372] ? mutex_lock_io_nested+0x1900/0x1900 [ 23.432180] ? vm_mmap_pgoff+0x1ed/0x280 [ 23.436207] ? userfaultfd_unmap_complete+0x327/0x510 [ 23.441362] lock_acquire+0x1d5/0x580 [ 23.445129] ? lock_acquire+0x1d5/0x580 [ 23.449077] ? shmem_file_llseek+0xef/0x240 [ 23.453366] ? lock_release+0xa40/0xa40 [ 23.457306] ? trace_event_raw_event_sched_switch+0x800/0x800 [ 23.463161] ? rcu_note_context_switch+0x710/0x710 [ 23.468061] ? __fget_light+0x297/0x380 [ 23.472002] ? __might_sleep+0x95/0x190 [ 23.475947] down_write+0x87/0x120 [ 23.479459] ? shmem_file_llseek+0xef/0x240 [ 23.483753] ? down_read+0x150/0x150 [ 23.487443] ? selinux_capable+0x40/0x40 [ 23.491475] shmem_file_llseek+0xef/0x240 [ 23.495589] ? shmem_free_swap+0x80/0x80 [ 23.499613] vfs_llseek+0xa2/0xd0 [ 23.503052] ashmem_llseek+0xe7/0x1f0 [ 23.506817] ? ashmem_read_iter+0x230/0x230 [ 23.511109] SyS_lseek+0xeb/0x170 [ 23.514530] entry_SYSCALL_64_fastpath+0x23/0x9a [ 23.519249] RIP: 0033:0x444ac9 [ 23.522402] RSP: 002b:00007ffc6ae26748 EFLAGS: 00000217 ORIG_RAX: 0000000000000008 [ 23.530074] RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000444ac9 [ 23.537313] RDX: 0000000000000003 RSI: 0000000000000000 RDI: 0000000000000004 [ 23.544556] RBP: 00000000