From mboxrd@z Thu Jan  1 00:00:00 1970
From: Patrick McHardy <kaber@trash.net>
Subject: Re: [RFC] x_tables: misuse of try_then_request_module
Date: Mon, 14 Mar 2011 19:21:37 +0100
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References: <20110308172318.4992a3a6@nehalam>	<4D777F6A.2020108@trash.net> <20110309074820.3094fa5d@s6510>
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Cc: Pablo Neira Ayuso <pablo@netfilter.org>,
	David Miller <davem@davemloft.net>,
	netfilter-devel@vger.kernel.org
To: Stephen Hemminger <shemminger@vyatta.com>
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On 09.03.2011 16:48, Stephen Hemminger wrote:
> On Wed, 09 Mar 2011 14:23:54 +0100
> Patrick McHardy <kaber@trash.net> wrote:
> 
>> Am 09.03.2011 02:23, schrieb Stephen Hemminger:
>>> Since xt_find_match() returns ERR_PTR(xx) on error not NULL,
>>> the macro try_then_request_module won't work correctly here.
>>> The macro expects its first argument will be zero if condition
>>> fails. But ERR_PTR(-ENOENT) is not zero.
>>>
>>> The correct solution is to propagate the error value
>>> back.
>>>
>>> Found by inspection, and compile tested only.
>>
>> Thanks Stephen. It actually works fine since we don't return
>> -ENOENT but 0 if nothing was found. If a non-matching revision
>> was found we return -EPROTOTYPE, but that case can only happen
>> if the module was already loaded.
>>
>> Anyways, this seems quite fragile, so I've applied your patch.
> 
> Ok, then change "err = 0" to "err = -ENOENT" at start of xt_find_match
> 

I fixed that up, thanks.