linux-kernel - Re: [PATCH 1/1] UBSAN: use uppercase K to format a kernel pointer

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Date:	Sat, 30 Jul 2016 10:26:31 +0200
From:	Nicolas Iooss <nicolas.iooss_linux@....org>
To:	Joe Perches <joe@...ches.com>,
	Andrey Ryabinin <aryabinin@...tuozzo.com>
Cc:	Andrew Morton <akpm@...ux-foundation.org>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/1] UBSAN: use uppercase K to format a kernel pointer

On 07/29/2016 09:53 PM, Joe Perches wrote:
> On Fri, 2016-07-29 at 13:10 +0200, Nicolas Iooss wrote:
>> handle_object_size_mismatch() used %pk to format a kernel pointer in
>> pr_err().  This seems to be a misspelling for %pK.
> 
> Thanks

Thanks for your feedbacks. I agree %pK does not make much sense in the
context it is used. I will modify this patch to use %p instead.

>> diff --git a/lib/ubsan.c b/lib/ubsan.c
> []
>> @@ -308,7 +308,7 @@ static void handle_object_size_mismatch(struct
>> type_mismatch_data *data,
>>  		return;
>>  
>>  	ubsan_prologue(&data->location, &flags);
>> -	pr_err("%s address %pk with insufficient space\n",
>> +	pr_err("%s address %pK with insufficient space\n",
>>  		type_check_kinds[data->type_check_kind],
>>  		(void *) ptr);
>>  	pr_err("for an object of type %s\n", data->type->type_name);
> 
> Maybe change this to a single output line:
> 
> 	pr_err("%s address %pK with insufficient space for an object of type %s\n",
> 	       type_check_kinds[data->type_check_kind], (void *)ptr,
> 	       data->type->type_name);

As both handle_missaligned_access() and handle_object_size_mismatch()
use two pr_err() calls to display their error messages, it seems the
split has been made on purpose (maybe to avoid logging long lines).
I won't merge the calls in my patch as this appears to be more an
ergonomic subject for people really using this code.

-- Nicolas