Re: [PATCH] pkt_sched: QFQ Plus: fair-queueing service at DRR cost

From: Stephen Hemminger <redacted>
Date: Tue, 20 Nov 2012 10:09:58 -0800

On Tue, 20 Nov 2012 13:02:02 -0500 (EST)
David Miller [off-list ref] wrote:

quoted

From: Stephen Hemminger <redacted>
Date: Tue, 20 Nov 2012 09:53:04 -0800

quoted

There are actually lots of bogus warnings than seem to only occur
because gcc 4.4 does a bad job of checking. Later versions are fixed
and don't generate warnings.

My preference is to not add the unnecessary initialization because
if you get in the habit of doing it. The whole purpose of the uninitialized
check is lost. 

Try again, this was with gcc-4.7.2-2 on Fedora.

There are too many preconditions, across multiple basic block, which
together ensure the skb is in fact initialized at the point in
question and the compiler simply isn't sophisticated enough to see
that.

Weird, it compiles  clean on x86-84 on Debian.
gcc-4.7.real (Debian 4.7.2-4) 4.7.2

Fedora backports a lot more stuff into gcc than Debian does.