Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751670AbYJRIXQ (ORCPT ); Sat, 18 Oct 2008 04:23:16 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750787AbYJRIXE (ORCPT ); Sat, 18 Oct 2008 04:23:04 -0400 Received: from mx2.mail.elte.hu ([157.181.151.9]:57282 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750745AbYJRIXA (ORCPT ); Sat, 18 Oct 2008 04:23:00 -0400 Date: Sat, 18 Oct 2008 10:22:09 +0200 From: Ingo Molnar To: Roland Dreier Cc: Linus Torvalds , Andrew Morton , "David S. Miller" , Alan Cox , linux-kernel@vger.kernel.org, Peter Zijlstra , Thomas Gleixner , "H. Peter Anvin" , David Howells Subject: Re: [announce] new tree: "fix all build warnings, on all configs" Message-ID: <20081018082209.GA24220@elte.hu> References: <20081017171139.GA1792@elte.hu> <20081017180523.GA11590@elte.hu> <20081017191202.GA5396@elte.hu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.18 (2008-05-17) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00,DNS_FROM_SECURITYSAGE autolearn=no SpamAssassin version=3.2.3 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] 0.0 DNS_FROM_SECURITYSAGE RBL: Envelope sender in blackholes.securitysage.com Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2657 Lines: 77 * Roland Dreier wrote: > > i certainly have a found a couple of such cases, see tip/warnings/ugly - > > for example see the one below where gcc is not able to see through type > > width. > > Yes, the uninitialized variable warnings are obnoxious too. By the way, > I think this: > > @@ -72,7 +72,7 @@ static __always_inline void *__constant_memcpy(void *to, const void *from, > return to; > case 5: > *(int *)to = *(int *)from; > - *((char *)to + 4) = *((char *)from + 4); > + *((short *)to + 3) = *((short *)from + 3); > return to; > case 6: > *(int *)to = *(int *)from; > > is actually *wrong*, because the cast operator binds tighter than > addition -- so > > + *((short *)to + 3) = *((short *)from + 3); > > actually copies bytes at offset 6 and 7; I think what you intended was: > > + *((short *)(to + 3)) = *((short *)(from + 3)); thx, you are right - fixed it via the patch below. > which illustrates the risks in fixing warnings. yeah. Note that this was not a routine case at all, i did the commit in the early stages when i didnt even know how much effort it all would be to keep the whole kernel warning-free, in all configs. It looked odd and ugly and was in tip/warnings/ugly rightfully. It would be nice if you could find an outright incorrect change in tip/warnings/simple. The ones flagged 'simple' are the ones that have the highest risk of not being reviewed much beyond their initial addition. Ingo ---------------> >From 9d8f9578ca252bf26474ed77fde7ea30e9dee595 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Sat, 18 Oct 2008 10:17:36 +0200 Subject: [PATCH] hack, workaround for warning drivers/acpi/tables/tbfadt.c, fix Fix commit fbf03326a16b29f8d34a5a3883a267bac4d38fc2, pointed out by Roland Dreier. Signed-off-by: Ingo Molnar --- include/asm-x86/string_32.h | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/include/asm-x86/string_32.h b/include/asm-x86/string_32.h index 419ab10..be82619 100644 --- a/include/asm-x86/string_32.h +++ b/include/asm-x86/string_32.h @@ -72,7 +72,7 @@ static __always_inline void *__constant_memcpy(void *to, const void *from, return to; case 5: *(int *)to = *(int *)from; - *((short *)to + 3) = *((short *)from + 3); + *((char *)(to + 3)) = *((char *)(from + 3)); return to; case 6: *(int *)to = *(int *)from; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/