From mboxrd@z Thu Jan  1 00:00:00 1970
From: "Alexey Zaytsev" <alexey.zaytsev@gmail.com>
Subject: Re: [PATCH] Null ctype should have ptr_ctype as its base type.
Date: Mon, 29 Dec 2008 12:03:07 +0300
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To: Christopher Li <sparse@chrisli.org>
Cc: linux-sparse@vger.kernel.org

On Mon, Dec 29, 2008 at 10:32, Christopher Li <sparse@chrisli.org> wrote:
> On Sun, Dec 28, 2008 at 1:38 PM, Alexey Zaytsev
> <alexey.zaytsev@gmail.com> wrote:
>> 11091a11093,11130
>>> drivers/net/wireless/wavelan_cs.c:362:16: error: subtraction of different types can't work (different base types)
>>> drivers/net/wireless/wavelan_cs.c:379:17: error: subtraction of different types can't work (different base types)
>>> drivers/net/wireless/wavelan_cs.c:385:21: error: subtraction of different types can't work (different base types)
>> [...]
>>
>> It looks like:
>>
>> ... mmroff(0, mmr_fee_status) ..
>>
>> #define mmroff(p,f)     (unsigned short)((void *)(&((mmr_t *)((void
>> *)0 + (p)))->f) - (void *)0)
>
> That is one piece of ugly code.
>
>>
>> mmr_fee_status being an element in struct mmr.
>> Here we end up substracting null from non-null void * pointer.
>> Looks quite pointless, but I think sparse should be able to
>> cope with this?
>
> Do you have minimal code to duplicate this bug?

Sorry, my bad. Ran it with a wrong sparse version.