From: Borislav Petkov <bp@alien8.de>
To: Ingo Molnar <mingo@kernel.org>
Cc: Arjun Sreedharan <arjun024@gmail.com>,
"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 15:28:00 +0100 [thread overview]
Message-ID: <20150317142800.GA31115@pd.tnic> (raw)
In-Reply-To: <20150317074608.GB27687@gmail.com>
On Tue, Mar 17, 2015 at 08:46:08AM +0100, Ingo Molnar wrote:
> I'd also add the following to the changelog:
Added:
---
From: Arjun Sreedharan <arjun024@gmail.com>
Date: Mon, 16 Mar 2015 21:07:47 +0530
Subject: [PATCH] x86/boot: Standardize strcmp()
strcmp() is always expected to return 0 when arguments are equal,
negative when its first argument @str1 is less than its second argument
@str2 and a positive value otherwise. Previously strcmp("a", "b")
returned 1. Now it gives -1, as it is supposed to.
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.
Signed-off-by: Arjun Sreedharan <arjun024@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Link: http://lkml.kernel.org/r/1426520267-1803-1-git-send-email-arjun024@gmail.com
Signed-off-by: Borislav Petkov <bp@suse.de>
---
arch/x86/boot/string.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/boot/string.c b/arch/x86/boot/string.c
index 493f3fd9f139..318b8465d302 100644
--- a/arch/x86/boot/string.c
+++ b/arch/x86/boot/string.c
@@ -30,7 +30,7 @@ int strcmp(const char *str1, const char *str2)
int delta = 0;
while (*s1 || *s2) {
- delta = *s2 - *s1;
+ delta = *s1 - *s2;
if (delta)
return delta;
s1++;
--
2.3.3
--
Regards/Gruss,
Boris.
ECO tip #101: Trim your mails when you reply.
--
next prev parent reply other threads:[~2015-03-17 14:29 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
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 [this message]
2015-03-23 12:23 ` [tip:x86/boot] x86/boot: Standardize strcmp() tip-bot for Arjun Sreedharan
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