Extraneous output when tracing writes from entry to return with output redirection to a file.

Fix: 

Work around:

Either continue to use self->flag or use the predicate

/this->flag && execname != "dtrace"/
How-To-Repeat: Consider the following script: test-bug.d

#!/usr/sbin/dtrace -s
#pragma D option quiet

vfs::vop_read:entry, vfs::vop_write:entry
/execname != "dtrace"/
{
        self->flag = 1;
}

vfs::vop_read:return, vfs::vop_write:return
/self->flag/
{
        this->flag = 1;
        self->flag = 0;
}

vfs::vop_read:return, vfs::vop_write:return
/this->flag/
{
        printf("%s\n", execname);
}

After running

dtrace -s test-bug.d -n 'tick-5s { exit(0); }' > /tmp/test

the file /tmp/test would contains lines with dtrace, which should not be there. Somehow dtrace has inherit the value of this->flag.