[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c.
[ 56.415622][ T27] audit: type=1800 audit(1582891711.913:25): pid=8792 uid=0 auid=4294967295 ses=4294967295 subj=_ op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2414 res=0
[ 56.444762][ T27] audit: type=1800 audit(1582891711.913:26): pid=8792 uid=0 auid=4294967295 ses=4294967295 subj=_ op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0
[ 56.487663][ T27] audit: type=1800 audit(1582891711.923:27): pid=8792 uid=0 auid=4294967295 ses=4294967295 subj=_ op=collect_data cause=failed(directio) comm="startpar" name="restorecond" dev="sda1" ino=2436 res=0
[....] Starting periodic command scheduler: cron[?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 '10.128.0.85' (ECDSA) to the list of known hosts.
executing program
syzkaller login: [ 67.421584][ T8947]
[ 67.424122][ T8947] =====================================
[ 67.429657][ T8947] WARNING: bad unlock balance detected!
[ 67.435241][ T8947] 5.6.0-rc3-syzkaller #0 Not tainted
[ 67.440999][ T8947] -------------------------------------
[ 67.447055][ T8947] syz-executor194/8947 is trying to release lock (&ovl_i_lock_key[depth]) at:
[ 67.455892][ T8947] [<ffffffff828b7835>] ovl_llseek+0x215/0x2c0
[ 67.462027][ T8947] but there are no more locks to release!
[ 67.467724][ T8947]
[ 67.467724][ T8947] other info that might help us debug this:
[ 67.475770][ T8947] 1 lock held by syz-executor194/8947:
[ 67.481235][ T8947] #0: ffff88809742ade0 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x279/0x310
[ 67.490019][ T8947]
[ 67.490019][ T8947] stack backtrace:
[ 67.495899][ T8947] CPU: 0 PID: 8947 Comm: syz-executor194 Not tainted 5.6.0-rc3-syzkaller #0
[ 67.505637][ T8947] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
[ 67.515939][ T8947] Call Trace:
[ 67.519707][ T8947] dump_stack+0x1fb/0x318
[ 67.524014][ T8947] ? ovl_llseek+0x215/0x2c0
[ 67.528503][ T8947] print_unlock_imbalance_bug+0x20b/0x240
[ 67.534207][ T8947] ? iomap_apply+0x3f1/0x490
[ 67.539383][ T8947] lock_release+0x469/0x710
[ 67.543864][ T8947] ? ovl_llseek+0x215/0x2c0
[ 67.548359][ T8947] ? ovl_llseek+0x215/0x2c0
[ 67.552864][ T8947] __mutex_unlock_slowpath+0x80/0x5b0
[ 67.558218][ T8947] mutex_unlock+0xd/0x10
[ 67.562555][ T8947] ovl_llseek+0x215/0x2c0
[ 67.566874][ T8947] __x64_sys_lseek+0x15f/0x1f0
[ 67.571808][ T8947] do_syscall_64+0xf7/0x1c0
[ 67.576299][ T8947] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[ 67.582286][ T8947] RIP: 0033:0x445df9
[ 67.586162][ T8947] Code: e8 ac b8 02 00 48 83 c4 18 c3 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 2b 12 fc ff c3 66 2e 0f 1f 84 00 00 00 00
[ 67.606605][ T8947] RSP: 002b:00007ff735aecce8 EFLAGS: 00000246 ORIG_RAX: 0000000000000008
[ 67.615006][ T8947] RAX: ffffffffffffffda RBX: 00000000006dac38 RCX: 0000000000445df