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From:   Krzysztof Kozlowski <krzk@kernel.org>
Date:   Wed, 21 Apr 2021 16:19:03 +0200
Message-ID: <CAJKOXPcyJ43m-n=ACGGgRZkWd8KDD5pNkBSY1mSOebH9BvHROA@mail.gmail.com>
Subject: Re: [PATCH] net/rds: Avoid potential use after free in rds_send_remove_from_sock
To:     Leon Romanovsky <leon@kernel.org>,
        "David S. Miller" <davem@davemloft.net>
Cc:     Jakub Kicinski <kuba@kernel.org>, Aditya Pakki <pakki001@umn.edu>,
        Santosh Shilimkar <santosh.shilimkar@oracle.com>,
        netdev@vger.kernel.org, linux-rdma@vger.kernel.org,
        rds-devel@oss.oracle.com,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
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On Tue, 20 Apr 2021 at 11:13, Leon Romanovsky <leon@kernel.org> wrote:
>
> On Tue, Apr 20, 2021 at 12:09:06PM +0300, Leon Romanovsky wrote:
> > On Tue, Apr 06, 2021 at 07:09:12PM -0500, Aditya Pakki wrote:
> > > In case of rs failure in rds_send_remove_from_sock(), the 'rm' resource
> > > is freed and later under spinlock, causing potential use-after-free.
> > > Set the free pointer to NULL to avoid undefined behavior.
> > >
> > > Signed-off-by: Aditya Pakki <pakki001@umn.edu>
> > > ---
> > >  net/rds/message.c | 1 +
> > >  net/rds/send.c    | 2 +-
> > >  2 files changed, 2 insertions(+), 1 deletion(-)
> >
> > Dave, Jakub
> >
> > Please revert this patch, given responses from Eric and Al together
> > with this response from Greg here https://lore.kernel.org/lkml/YH5/i7OvsjSmqADv@kroah.com
>
> https://lore.kernel.org/lkml/YH5%2Fi7OvsjSmqADv@kroah.com/
>
> >
> > BTW, I looked on the rds code too and agree with Eric, this patch
> > is a total garbage.

When reverting, consider giving credits to Kees/Coverity as he pointed
out after testing linux-next that this is bogus:
https://lore.kernel.org/linux-next/202104081640.1A09A99900@keescook/


Best regards,
Krzysztof