linux-kernel - Re: [PATCH 167/190] Revert "gdrom: fix a memory leak bug"

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Date:   Tue, 27 Apr 2021 15:01:22 +0200
From:   Greg KH <gregkh@...uxfoundation.org>
To:     Jens Axboe <axboe@...nel.dk>
Cc:     Peter Rosin <peda@...ntia.se>, linux-kernel@...r.kernel.org,
        wang6495@....edu
Subject: Re: [PATCH 167/190] Revert "gdrom: fix a memory leak bug"

On Fri, Apr 23, 2021 at 08:20:30AM -0600, Jens Axboe wrote:
> 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.

Thanks for the review from both of you, I'll keep this commit in the
tree.

greg k-h