[....] Starting enhanced syslogd: rsyslogd[ 15.289105] audit: type=1400 audit(1520662352.834:4): avc: denied { syslog } for pid=3650 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 Warning: Permanently added '10.128.10.14' (ECDSA) to the list of known hosts. 2018/03/10 06:12:45 parsed 1 programs 2018/03/10 06:12:45 executed programs: 0 syzkaller login: [ 28.220459] IPVS: Creating netns size=2536 id=1 [ 28.238373] [ 28.240011] ====================================================== [ 28.246301] [ INFO: possible circular locking dependency detected ] [ 28.252674] 4.9.86-g00db063 #60 Not tainted [ 28.256960] ------------------------------------------------------- [ 28.263332] syz-executor0/3819 is trying to acquire lock: [ 28.268833] (&mm->mmap_sem){++++++}, at: [] __might_fault+0xe4/0x1d0 [ 28.277305] but task is already holding lock: [ 28.281940] (ashmem_mutex){+.+.+.}, at: [] ashmem_ioctl+0x371/0xfe0 [ 28.290321] which lock already depends on the new lock. [ 28.290321] [ 28.297307] [ 28.297307] the existing dependency chain (in reverse order) is: [ 28.304900] -> #1 (ashmem_mutex){+.+.+.}: [ 28.309677] lock_acquire+0x12e/0x410 [ 28.313967] mutex_lock_nested+0xbb/0x870 [ 28.318607] ashmem_mmap+0x53/0x400 [ 28.322724] mmap_region+0x7dd/0xfd0 [ 28.326925] do_mmap+0x57b/0xbe0 [ 28.330780] vm_mmap_pgoff+0x16b/0x1b0 [ 28.335162] SyS_mmap_pgoff+0x33f/0x560 [ 28.339628] do_fast_syscall_32+0x2f5/0x870 [ 28.344441] entry_SYSENTER_compat+0x90/0xa2 [ 28.349335] -> #0 (&mm->mmap_sem){++++++}: [ 28.354181] __lock_acquire+0x2bf9/0x3640 [ 28.358914] lock_acquire+0x12e/0x410 [ 28.363205] __might_fault+0x14a/0x1d0 [ 28.367582] ashmem_ioctl+0x3c0/0xfe0 [ 28.371870] compat_ashmem_ioctl+0x3e/0x50 [ 28.376594] compat_SyS_ioctl+0x15f/0x2050 [ 28.381320] do_fast_syscall_32+0x2f5/0x870 [ 28.386133] entry_SYSENTER_compat+0x90/0xa2 [ 28.391028] [ 28.391028] other info that might help us debug this: [ 28.391028] [ 28.399143] Possible unsafe locking scenario: [ 28.399143] [ 28.405166] CPU0 CPU1 [ 28.409801] ---- ---- [ 28.414436] lock(ashmem_mutex); [ 28.418261] lock(&mm->mmap_sem); [ 28.424522] lock(ashmem_mutex); [ 28.430689] lock(&mm->mmap_sem); [ 28.434428] [ 28.434428] *** DEADLOCK *** [ 28.434428] [ 28.440457] 1 lock held by syz-executor0/3819: [ 28.445004] #0: (ashmem_mutex){+.+.+.}, at: [] ashmem_ioctl+0x371/0xfe0 [ 28.453932] [ 28.453932] stack backtrace: [ 28.458397] CPU: 0 PID: 3819 Comm: syz-executor0 Not tainted 4.9.86-g00db063 #60 [ 28.465897] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 28.475220] ffff8801d894fa38 ffffffff81d956f9 ffffffff853a5db0 ffffffff853a5db0 [ 28.483189] ffffffff853c5490 ffff8801d95fe8d8 ffff8801d95fe000 ffff8801d894fa80 [ 28.491166] ffffffff812387f1 ffff8801d95fe8d8 00000000d95fe8b0 ffff8801d95fe8d8 [ 28.499133] Call Trace: [ 28.501691] [] dump_stack+0xc1/0x128 [ 28.507028] [] print_circular_bug+0x271/0x310 [ 28.513142] [] __lock_acquire+0x2bf9/0x3640 [ 28.519091] [] ? avc_has_extended_perms+0x3fc/0xf10 [ 28.525725] [] ? avc_has_extended_perms+0xe2/0xf10 [ 28.532277] [] ? debug_check_no_locks_freed+0x2c0/0x2c0 [ 28.539261] [] ? mark_held_locks+0xaf/0x100 [ 28.545203] [] ? mutex_lock_nested+0x5e3/0x870 [ 28.551417] [] ? __lock_is_held+0xa1/0xf0 [ 28.557191] [] lock_acquire+0x12e/0x410 [ 28.562785] [] ? __might_fault+0xe4/0x1d0 [ 28.568565] [] __might_fault+0x14a/0x1d0 [ 28.574245] [] ? __might_fault+0xe4/0x1d0 [ 28.580015] [] ashmem_ioctl+0x3c0/0xfe0 [ 28.585607] [] ? selinux_file_ioctl+0x355/0x530 [ 28.591893] [] ? selinux_capable+0x40/0x40 [ 28.597750] [] ? get_name+0x250/0x250 [ 28.603174] [] ? compat_SyS_futex+0x1f9/0x2a0 [ 28.609286] [] compat_ashmem_ioctl+0x3e/0x50 [ 28.615313] [] compat_SyS_ioctl+0x15f/0x2050 [ 28.62134