[....] Starting enhanced syslogd: rsyslogd[ 15.519617] audit: type=1400 audit(1520496910.983:4): avc: denied { syslog } for pid=3633 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[1G[[32m ok [39;49m8[?25h[?0c.
[....] Starting periodic command scheduler: cron[?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c.
Starting mcstransd:
[....] Starting file context maintaining daemon: restorecond[?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c.
[....] Starting OpenBSD Secure Shell server: sshd[?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c.
Debian GNU/Linux 7 syzkaller ttyS0
Warning: Permanently added '10.128.0.41' (ECDSA) to the list of known hosts.
2018/03/08 08:15:22 parsed 1 programs
2018/03/08 08:15:22 executed programs: 0
syzkaller login: [ 27.437478] IPVS: Creating netns size=2536 id=1
[ 27.455449]
[ 27.457089] ======================================================
[ 27.463377] [ INFO: possible circular locking dependency detected ]
[ 27.469754] 4.9.86-gd3a2afb #59 Not tainted
[ 27.474044] -------------------------------------------------------
[ 27.480419] syz-executor0/3801 is trying to acquire lock:
[ 27.485938] (&mm->mmap_sem){++++++}, at: [<ffffffff814c26d4>] __might_fault+0xe4/0x1d0
[ 27.494435] but task is already holding lock:
[ 27.499075] (ashmem_mutex){+.+.+.}, at: [<ffffffff82d4b121>] ashmem_ioctl+0x371/0xfe0
[ 27.507474] which lock already depends on the new lock.
[ 27.507474]
[ 27.514466]
[ 27.514466] the existing dependency chain (in reverse order) is:
[ 27.522065]
-> #1 (ashmem_mutex){+.+.+.}:
[ 27.526848] lock_acquire+0x12e/0x410
[ 27.531162] mutex_lock_nested+0xbb/0x870
[ 27.535801] ashmem_mmap+0x53/0x400
[ 27.539918] mmap_region+0x7dd/0xfd0
[ 27.544131] do_mmap+0x57b/0xbe0
[ 27.547989] vm_mmap_pgoff+0x16b/0x1b0
[ 27.552369] SyS_mmap_pgoff+0x33f/0x560
[ 27.556846] do_fast_syscall_32+0x2f5/0x870
[ 27.561660] entry_SYSENTER_compat+0x90/0xa2
[ 27.566558]
-> #0 (&mm->mmap_sem){++++++}:
[ 27.571414] __lock_acquire+0x2bf9/0x3640
[ 27.576051] lock_acquire+0x12e/0x410
[ 27.580345] __might_fault+0x14a/0x1d0
[ 27.584725] ashmem_ioctl+0x3c0/0xfe0
[ 27.589016] compat_ashmem_ioctl+0x3e/0x50
[ 27.593744] compat_SyS_ioctl+0x15f/0x2050
[ 27.598471] do_fast_syscall_32+0x2f5/0x870
[ 27.603286] entry_SYSENTER_compat+0x90/0xa2
[ 27.608191]
[ 27.608191] other info that might help us debug this:
[ 27.608191]
[ 27.616313] Possible unsafe locking scenario:
[ 27.616313]
[ 27.622341] CPU0 CPU1
[ 27.626977] ---- ----
[ 27.631612] lock(ashmem_mutex);
[ 27.635268] lock(&mm->mmap_sem);
[ 27.641525] lock(ashmem_mutex);
[ 27.647702] lock(&mm->mmap_sem);
[ 27.651446]
[ 27.651446] *** DEADLOCK ***
[ 27.651446]
[ 27.657473] 1 lock held by syz-executor0/3801:
[ 27.662021] #0: (ashmem_mutex){+.+.+.}, at: [<ffffffff82d4b121>] ashmem_ioctl+0x371/0xfe0
[ 27.670966]
[ 27.670966] stack backtrace:
[ 27.675436] CPU: 1 PID: 3801 Comm: syz-executor0 Not tainted 4.9.86-gd3a2afb #59
[ 27.682938] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
[ 27.692269] ffff8801bc56fa38 ffffffff81d956f9 ffffffff853a5db0 ffffffff853a5db0
[ 27.700255] ffffffff853c5640 ffff8801d7b0e8d8 ffff8801d7b0e000 ffff8801bc56fa80
[ 27.708235] ffffffff812387f1 ffff8801d7b0e8d8 00000000d7b0e8b0 ffff8801d7b0e8d8
[ 27.716235] Call Trace:
[ 27.718797] [<ffffffff81d956f9>] dump_stack+0xc1/0x128
[ 27.724143] [<ffffffff812387f1>] print_circular_bug+0x271/0x310
[ 27.730258] [<ffffffff8123ec29>] __lock_acquire+0x2bf9/0x3640
[ 27.736202] [<ffffffff81bdad0c>] ? avc_has_extended_perms+0x3fc/0xf10
[ 27.742838] [<ffffffff81bda9f2>] ? avc_has_extended_perms+0xe2/0xf10
[ 27.749406] [<ffffffff8123c030>] ? debug_check_no_locks_freed+0x2c0/0x2c0
[ 27.756389] [<ffffffff8123b41f>] ? mark_held_locks+0xaf/0x100
[ 27.762333] [<ffffffff838abd83>] ? mutex_lock_nested+0x5e3/0x870
[ 27.768536] [<ffffffff81234d01>] ? __lock_is_held+0xa1/0xf0
[ 27.774313] [<ffffffff812400ae>] lock_acquire+0x12e/0x410
[ 27.779919] [<ffffffff814c26d4>] ? __might_fault+0xe4/0x1d0
[ 27.785685] [<ffffffff814c273a>] __might_fault+0x14a/0x1d0
[ 27.791367] [<ffffffff814c26d4>] ? __might_fault+0xe4/0x1d0
[ 27.797146] [<ffffffff82d4b170>] ashmem_ioctl+0x3c0/0xfe0
[ 27.802739] [<ffffffff81beb275>] ? selinux_file_ioctl+0x355/0x530
[ 27.809032] [<ffffffff81beaf20>] ? selinux_capable+0x40/0x40
[ 27.814886] [<ffffffff82d4adb0>] ? get_name+0x250/0x250
[ 27.820307] [<ffffffff812e5fd9>] ? compat_SyS_futex+0x1f9/0x2a0
[ 27.826423] [<ffffffff82d4bdce>] compat_ashmem_ioctl+0x3e/0x50
[ 27.832473] [<ffffffff8167d38f>] compat_SyS_ioctl+0x15f/0x2050
[ 27.83