Re: [PATCH] x86,boot: standardize strcmp()

From: Ingo Molnar
Date: Tue Mar 17 2015 - 03:46:21 EST



* Arjun Sreedharan <arjun024@xxxxxxxxx> 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
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/