Do not use "guru" as debug level.
See this code from gnupg:
else if (!strcmp (level, "guru") || numok) { opt.debug = ~0; /* Unless the "guru" string has been used we don't want to allow hashing debugging. The rationale is that people tend to select the highest debug value and would then clutter their disk with debug files which may reveal confidential data. */ if (numok) opt.debug &= ~(DBG_HASHING_VALUE); }