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From: Ingo Molnar <mingo@kernel.org>
To: Arjun Sreedharan <arjun024@gmail.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>,
	x86@kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] x86,boot: standardize strcmp()
Date: Tue, 17 Mar 2015 08:46:08 +0100	[thread overview]
Message-ID: <20150317074608.GB27687@gmail.com> (raw)
In-Reply-To: <1426520267-1803-1-git-send-email-arjun024@gmail.com>


* Arjun Sreedharan <arjun024@gmail.com> wrote:

> strcmp() is always expected to return 0 when args are
> same, <0 when arg1 is lesser and >0 otherwise.
> Previously strcmp("a","b") returned 1. Now it gives -1.

I'd also add the following to the changelog:

Until now this bug never triggered, because all uses for strcmp() in 
the boot code tested for nonzero:

 triton:~/tip> git grep strcmp arch/x86/boot/
 arch/x86/boot/boot.h:int strcmp(const char *str1, const char *str2);
 arch/x86/boot/edd.c:            if (!strcmp(eddarg, "skipmbr") || !strcmp(eddarg, "skip")) {
 arch/x86/boot/edd.c:            else if (!strcmp(eddarg, "off"))
 arch/x86/boot/edd.c:            else if (!strcmp(eddarg, "on"))

should in the future strcmp() be used in a comparative way in the boot 
code, it might have led to (not so subtle) bugs.

Thanks,

	Ingo

  parent reply	other threads:[~2015-03-17  7:46 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-03-16 15:37 [PATCH] x86,boot: standardize strcmp() Arjun Sreedharan
2015-03-16 18:16 ` Borislav Petkov
2015-03-17  7:46 ` Ingo Molnar [this message]
2015-03-17 14:13   ` Arjun Sreedharan
2015-03-18  1:36     ` Bernd Petrovitsch
2015-03-18 18:10       ` Arjun Sreedharan
2015-03-18 18:37       ` Arjun Sreedharan
2015-03-19 17:34     ` H. Peter Anvin
2015-03-20 11:42       ` Bernd Petrovitsch
2015-03-17 14:28   ` Borislav Petkov
2015-03-23 12:23 ` [tip:x86/boot] x86/boot: Standardize strcmp() tip-bot for Arjun Sreedharan

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