Am 09.07.2012 19:01, schrieb Anthony Liguori: > On 07/09/2012 11:46 AM, Eric Blake wrote: >> On 07/09/2012 10:07 AM, Markus Armbruster wrote: >> >>>>> This is an unconditional use of fd_type[0]. If floppy == NULL, this is >>>>> dereferencing an uninitialized value. >>>>> >>>>> I'm not sure why the explicit initialization was removed... >>> >>> Brain fart on my part, sorry. The old loop assigns only if the drive >>> exists. The new loop assigns unconditionally. Except the whole loop is >>> still conditional. >>> >>> Testing can't flag this, because floppy is never null. >>> >>>> Looks broken indeed. I just wonder why my gcc (or the buildbots) didn't >>>> complain. >>> >>> Me too. Looks like I should upgrade to a more recent gcc. >> >> It's probably not the version of the gcc you used, but whether or not >> your CFLAGS include -O2. Gcc has the (IMO very annoying) limitation >> that uninitialized-use analysis can only be performed if you are also >> doing optimization. You have to use a tool like clang or Coverity if >> you want more reliable uninitialized-use analysis even while building >> -O0 debug images. >> > > Specifically, without -O, GCC doesn't do data flow analysis so any warning > that > requires DFA won't get triggered. > > So in general, if you are normally building with -O0, make sure to also build > with -O in order to get full warnings.
Just checked it to be sure, this doesn't seem to be the reason: CFLAGS=-O2 -D_FORTIFY_SOURCE=2 -g Kevin
