linux-kernel - Re: [PATCH] scripts/mod/modpost.c: Fix bug in number

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Message-ID: <87d2df768c.fsf@rustcorp.com.au>
Date:	Wed, 09 Jul 2014 09:28:43 +0930
From:	Rusty Russell <rusty@...tcorp.com.au>
To:	Rasmus Villemoes <linux@...musvillemoes.dk>,
	Paul Gortmaker <paul.gortmaker@...driver.com>
Cc:	"H. Peter Anvin" <hpa@...ux.intel.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	linux-kernel@...r.kernel.org, Sam Ravnborg <sam@...nborg.org>
Subject: Re: [PATCH] scripts/mod/modpost.c: Fix bug in number_prefix

Rasmus Villemoes <linux@...musvillemoes.dk> writes:
> Paul Gortmaker <paul.gortmaker@...driver.com> writes:
>
>> On 14-06-25 04:46 AM, Rasmus Villemoes wrote:
>>> The function number_prefix() can currently only return 1 if its
>>> argument is the empty string: If line 3 is reached and *sym (now the
>>> second character in the argument) is not '.', 0 is returned. However,
>>> if that character is '.', the first assignment to c is that same '.',
>>> which obviously fails to be a digit.
>>
>> I'd suggest you expand the commit log to actually list the end-user
>> visible symptom and the use case that this actually fixes, since it
>> isn't obvious to me at all.
>
> Sorry, it isn't obvious to me either. I just stumbled on it reading the
> code; the rest of modpost.c is too deep magic for me.

The function is horribly mis-named which doesn't help ("number_postfix"
would be closer).

And yes, it's completely broken.

Sam, this never worked, and was clearly never tested.  Seems like we
should just rip out the '$' postfix then, or are you aware of platforms
which have been ignoring modpost complaints since 2008?

Cheers,
Rusty.
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