On Friday 15 March 2013, Russell King - ARM Linux wrote: > On Fri, Mar 15, 2013 at 02:55:38PM +0000, Arnd Bergmann wrote: > > I'd like to merge this for 3.9 and also for the stable kernels, > > if people agree this is a good idea. > > I think I replied to your previous version recently asking whether > this affects real uninitialized variables too. If gcc can prove that there is a code path in which the variable is used uninitialized, it will still warn with this patch, since we are leaving -Wuninitialized enabled but only disable -Wmaybe-uninitilized. There are obviously some cases where gcc correctly warns today but cannot prove whether or not this is actually possible. I don't have any data about how often we'd see one or the other, but I would expect the first one to be more common. We'd also still see all valid warnings with the Kconfig default of building with -O2 rather than -Os, and as gcc gets smarter over time, it should show more of the real bugs with -Wuninitialized. I think the real trade-off is that not applying this patch will cause more patches to get merged that add bogus initializations, which definitely prevent gcc from warning about a real uninitialized variable bug in that function again. I have done some of those patches myself in the past, but it always feels really wrong to do those. Arnd -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
