Re: [GIT PULL] core/locking changes for v3.1

[Linus Torvalds]

On Mon, Jul 25, 2011 at 12:04 PM, Ingo Molnar <mingo@xxxxxxx> wrote:
> ..
> net/netfilter/nf_conntrack_core.c: In function ‘nf_conntrack_init’:
> net/netfilter/nf_conntrack_core.c:1579:3: warning: the comparison
> will always evaluate as ‘true’ for the address of
> ‘nf_conntrack_attach’ will never be NULL [-Waddress]

These all seem to be essentially compiler bugs.

We have macros that do generic things (in this case
"rcu_assign_pointer()" and tests their values. The fact that the tests
sometimes end up being statically true (or false) is not something the
compiler should complain about - it should use it to optimize the
code.

Sad.

We can make a compiler bug-report, or disable -Waddress. Or maybe we
can write the tests in a way that doesn't trigger the compiler bug.

This same issue is why I hated -Wsign-compare. Some of the things gcc
complained about were just technically moronic. So compiler warnings
are not always a good thing.

                  Linus
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