Enable -Wuninitialized

[nathanchance]

29b00e6 would have been caught with Clang in its default configuration (and not by GCC due to a bug), as pointed out in this thread: https://lore.kernel.org/lkml/86649ee4-9794-77a3-502c-f4cd10019c36@lca.pw/

However, -Wuninitialized also disables -Wsometimes-uninitialized so this was missed by both compilers :(

I am going to test the following diff then send it along right away if there are no additional warnings:

diff --git a/scripts/Makefile.extrawarn b/scripts/Makefile.extrawarn
index 768306add591..f4332981ea85 100644
--- a/scripts/Makefile.extrawarn
+++ b/scripts/Makefile.extrawarn
@@ -72,5 +72,6 @@ KBUILD_CFLAGS += $(call cc-disable-warning, format)
 KBUILD_CFLAGS += $(call cc-disable-warning, sign-compare)
 KBUILD_CFLAGS += $(call cc-disable-warning, format-zero-length)
 KBUILD_CFLAGS += $(call cc-disable-warning, uninitialized)
+KBUILD_CFLAGS += $(call cc-option, -Wsometimes-uninitialized)
 endif
 endif

Side note, looks like this might be a good time to tell Linus about the KernelCI work that is going on: https://lore.kernel.org/lkml/CAHk-=wggjLsi-1BmDHqWAJPzBvTD_-MQNo5qQ9WCuncnyWPROg@mail.gmail.com/

[nickdesaulniers]

heh, wish I was cc'ed on that thread (I'm not subbed to lkml, ducks)

[nathanchance]

I'm not subbed to lkml, ducks

Neither am I, I happened to stumble across it while browsing https://lore.kernel.org/lkml/. Guess I should be after this.

It is still possible to reply without being CC'd (if you use mutt). Otherwise, the link gives reply instructions using git send-email at the bottom.

$ curl -LSs -o mbox https://lore.kernel.org/lkml/CAHk-=wggjLsi-1BmDHqWAJPzBvTD_-MQNo5qQ9WCuncnyWPROg@mail.gmail.com/raw
$ mutt -f mbox

[nathanchance]

Unfortunately, introduces a few warnings: https://gist.github.com/nathanchance/59f35754366c7d68141a5f44fe9302b8

Another project like #378 (seems like it could be achieved quicker).

[nickdesaulniers]

Yes; and many of those have the same source file (and even the same warning in some cases; like maybe a shared problematic macro). Thanks for the link; I'll file bugs for all of those, and we'll use this to track enabling the warning.