On Thu, 4 Dec 2014 08:30:32 -0800 Greg Kroah-Hartman <[email protected]> wrote:
> On Thu, Dec 04, 2014 at 03:13:00PM +0000, Prabhakar Lad wrote: > > On Thu, Dec 4, 2014 at 2:59 PM, Arnd Bergmann <[email protected]> wrote: > > > On Thursday 04 December 2014 14:38:30 Lad, Prabhakar wrote: > > >> this patch fixes following build warning: > > >> > > >> drivers/misc/ioc4.c: In function ___ioc4_probe___: > > >> drivers/misc/ioc4.c:194:16: warning: ___start___ may be used > > >> uninitialized in this function [-Wmaybe-uninitialized] > > >> period = (end - start) / > > >> ^ > > >> drivers/misc/ioc4.c:148:11: note: ___start___ was declared here > > >> uint64_t start, end, period; > > >> > > >> Signed-off-by: Lad, Prabhakar <[email protected]> > > > > > > Please explain why the compiler thinks there is a bug, why you > > > are sure that there isn't, and why you picked '0' as the > > > initialization value. > > > > > Its a false positive, to suppress the warning '0' was picked. > > Are you _sure_ it's a false positive? That odd do/while loop looks like > it might just not ever initialize the start variable, are you sure the > logic there is correct? > As long as IOC4_CALIBRATE_END is greater than IOC4_CALIBRATE_DISCARD (it is), `start' is written to. It would be nice to simplify the code, but I'm not sure how. And I really dislike this initialize-it-to-zero-to-stop-the-warning thing which we do all over the place. The reader doesn't know *why* it's initialized to zero and the initialization can conceal bugs if we get a code path which should have written to it but forgot to. And it adds unneeded code to vlinux. I much prefer unintialized_var() which fixes the documentation issue and doesn't add code. But Linus and Ingo had a dummy-spit over it. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
