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Date:   Tue, 18 May 2021 21:53:19 +0000
From:   Wei Liu <wei.liu@kernel.org>
To:     Long Li <longli@microsoft.com>
Cc:     Wei Liu <wei.liu@kernel.org>,
        Christophe JAILLET <christophe.jaillet@wanadoo.fr>,
        KY Srinivasan <kys@microsoft.com>,
        Haiyang Zhang <haiyangz@microsoft.com>,
        Stephen Hemminger <sthemmin@microsoft.com>,
        Dexuan Cui <decui@microsoft.com>,
        "gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
        "linux-hyperv@vger.kernel.org" <linux-hyperv@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "kernel-janitors@vger.kernel.org" <kernel-janitors@vger.kernel.org>
Subject: Re: [PATCH 1/2] uio_hv_generic: Fix a memory leak in error handling
 paths
Message-ID: <20210518215319.yshxwkvxaxsv77bv@liuwe-devbox-debian-v2>
References: <4fdaff557deef6f0475d02ba7922ddbaa1ab08a6.1620544055.git.christophe.jaillet@wanadoo.fr>
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On Tue, May 18, 2021 at 09:50:17PM +0000, Long Li wrote:
> > Subject: Re: [PATCH 1/2] uio_hv_generic: Fix a memory leak in error handling
> > paths
> > 
> > Cc Long Li.
> > 
> > Long, Stephen suggested I check with you. Do you have any opinion?
> > 
> > Wei.
> > 
> > On Tue, May 11, 2021 at 09:52:27AM +0000, Wei Liu wrote:
> > > On Sun, May 09, 2021 at 09:13:03AM +0200, Christophe JAILLET wrote:
> > > > If 'vmbus_establish_gpadl()' fails, the (recv|send)_gpadl will not
> > > > be updated and 'hv_uio_cleanup()' in the error handling path will
> > > > not be able to free the corresponding buffer.
> > > >
> > > > In such a case, we need to free the buffer explicitly.
> > > >
> > > > Fixes: cdfa835c6e5e ("uio_hv_generic: defer opening vmbus until
> > > > first use")
> > > > Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
> > > > ---
> > > > Before commit cdfa835c6e5e, the 'vfree' were done unconditionally in
> > > > 'hv_uio_cleanup()'.
> > > > So, another way for fixing the potential leak is to modify
> > > > 'hv_uio_cleanup()' and revert to the previous behavior.
> > > >
> > >
> > > I think this is cleaner.
> 
> Christophe has mentioned that the patch is already picked up by Greg KH.
> 
> I think both approaches are correct. We can go with this one.

OK. That's fine.

Wei.