linux-kernel - Re: [PATCH] platform/x86: alienware-wmi: fix kfree on potentially uninitialized pointer

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Message-ID: <424c2bba-1e17-3131-c15b-44462c57e22d@canonical.com>
Date:   Wed, 3 Apr 2019 23:05:12 +0100
From:   Colin Ian King <colin.king@...onical.com>
To:     Darren Hart <dvhart@...radead.org>
Cc:     Andy Shevchenko <andy@...radead.org>,
        platform-driver-x86@...r.kernel.org,
        kernel-janitors@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] platform/x86: alienware-wmi: fix kfree on potentially
 uninitialized pointer

On 03/04/2019 23:02, Darren Hart wrote:
> On Sat, Mar 30, 2019 at 12:17:12AM +0000, Colin King wrote:
>> From: Colin Ian King <colin.king@...onical.com>
>>
>> Currently the kfree of output.pointer can be potentially freeing
>> an uninitalized pointer in the case where out_data is NULL. Fix this
>> by reworking the case where out_data is not-null to perform the
>> ACPI status check and also the kfree of outpoint.pointer in one block
>> and hence ensuring the pointer is only freed when it has been used.
>>
>> Also replace the if (ptr != NULL) idiom with just if (ptr).
>>
>> Fixes: ff0e9f26288d ("platform/x86: alienware-wmi: Correct a memory leak")
>> Signed-off-by: Colin Ian King <colin.king@...onical.com>
> 
> Thanks for the catch Colin, queued for testing.
> 
> Did you trigger this error or detect it via review or static analysis?
> 
Static analysis, I'm now running a licensed version of Coverity on one
of our servers.

Colin