linux-kernel - Re: [PATCH] BUILD_BUG_ON() should not use array type

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Sat, 30 Aug 2008 03:38:15 +0400
From:	Alexey Dobriyan <adobriyan@...il.com>
To:	Andrew Morton <akpm@...ux-foundation.org>
Cc:	Jan Beulich <jbeulich@...ell.com>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] BUILD_BUG_ON() should not use array type

> > +/* Force a compilation error if condition is constant and true */
> > +#define MAYBE_BUILD_BUG_ON(cond) ((void)sizeof(char[1 - 2 * !!(cond)]))
> 
> MAYBE_BUILD_BUG_ON() hurts my brain.  It's doing:
> 
> 	if (__builtin_constant_p(expr))
> 		BUILD_BUG_ON(expr);
> 
> yes?  For inlined (or macro) callsites which can be used with constant
> or non-constant args.
> 
> It's tempting to just zap the one callsite and not add this at all,

Yes, please. There should be no maybes in kernel.

Imagine probabilistic BUG_ON(). Imagine probabilistic refcounting: maybe_get_net().

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/