On Sat, 27 Aug 2011 14:15:59 -0500 Larry Finger <Larry.Finger@xxxxxxxxxxxx> wrote: > On 08/27/2011 01:54 PM, Michael Büsch wrote: > > On Sat, 27 Aug 2011 13:26:00 -0500 > > Larry Finger<Larry.Finger@xxxxxxxxxxxx> wrote: > > > >> CHECK drivers/net/wireless/b43/main.c > >> drivers/net/wireless/b43/main.c +4115 b43_wireless_core_stop(7) warn: variable dereferenced before check 'dev' > > > >> This is next material. > > > > -next, just because the bug is not in the current kernel? > > Or because you think this is harmless? > > > > I'm not sure whether this is harmless. It effectively is that kind > > of bug that triggers dangerous compiler optimizations. > > I think the compiler has some freedom to assume dev can not be NULL when > > the function is entered and thus optimize out the !dev check. > > No, the check has to be left in due to the changing of dev in the routine > followed by a 'goto redo'. I think the compiler is still free to emit the !dev check twice. Or the other way around: Emit it correctly for the "goto" case and don't emit it for the function-enter case (and directly check dev->status). > In fact, a bug in the original code is unlikely, but my patch did add one. I > think the code should be > > if (!dev) > return NULL; > wl = dev->wl; > redo: yes -- Greetings, Michael. -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
