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Subject: Re: [PATCH 167/190] Revert "gdrom: fix a memory leak bug"
To:     Peter Rosin <peda@axentia.se>, gregkh@linuxfoundation.org
Cc:     linux-kernel@vger.kernel.org, wang6495@umn.edu
References: <20210421130105.1226686-168-gregkh@linuxfoundation.org>
 <23ffd3c5-0095-6a95-8c30-2b6f67377ce7@axentia.se>
From:   Jens Axboe <axboe@kernel.dk>
Message-ID: <14bdfbee-b8b9-d8ac-de34-b6d852d1485b@kernel.dk>
Date:   Fri, 23 Apr 2021 08:20:30 -0600
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On 4/22/21 3:29 PM, Peter Rosin wrote:
>> This reverts commit 093c48213ee37c3c3ff1cf5ac1aa2a9d8bc66017.
> 
> The reverted patch looks fishy.
> 
> gc.cd_info is kzalloc:ed on probe. In case probe fails after this allocation, the
> memory is kfree:d but the variable is NOT zeroed out.
> 
> AFAICT, the above leads to a double-free on exit by the added line.
> 
> I believe gd.cd_info should be kfree:d on remove instead.
> 
> However, might not gc.toc also be kfree:d twice for similar reasons?
> 
> I could easily be mistaken.

From taking a quick look the other day, that's my conclusion too. I
don't think the patch is correct, but I don't think the surrounding code
is correct right now either.

-- 
Jens Axboe