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References: <20220623074005.259309-1-ztong0001@gmail.com> <YrQw1CVJfIS18CNo@electric-eye.fr.zoreil.com>
 <20220624114121.2c95c3aa@kernel.org>
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From:   Tong Zhang <ztong0001@gmail.com>
Date:   Sat, 25 Jun 2022 21:45:00 -0700
Message-ID: <CAA5qM4Aq_2HSxCgaHUgZX9C3E0OCPT4tN-61-MZP1iLXCbF-=Q@mail.gmail.com>
Subject: Re: [PATCH] epic100: fix use after free on rmmod
To:     Jakub Kicinski <kuba@kernel.org>
Cc:     Francois Romieu <romieu@fr.zoreil.com>,
        "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Paolo Abeni <pabeni@redhat.com>,
        Florian Fainelli <f.fainelli@gmail.com>,
        Arnd Bergmann <arnd@arndb.de>, Jason Gunthorpe <jgg@ziepe.ca>,
        Jeff Kirsher <jeffrey.t.kirsher@intel.com>,
        Netdev <netdev@vger.kernel.org>,
        open list <linux-kernel@vger.kernel.org>,
        Yilun Wu <yiluwu@cs.stonybrook.edu>
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On Fri, Jun 24, 2022 at 11:41 AM Jakub Kicinski <kuba@kernel.org> wrote:
>
> On Thu, 23 Jun 2022 11:22:28 +0200 Francois Romieu wrote:
> > Tong Zhang <ztong0001@gmail.com> :
> > > epic_close() calls epic_rx() and uses dma buffer, but in epic_remove_one()
> > > we already freed the dma buffer. To fix this issue, reorder function calls
> > > like in the .probe function.
> > >
> > > BUG: KASAN: use-after-free in epic_rx+0xa6/0x7e0 [epic100]
> > > Call Trace:
> > >  epic_rx+0xa6/0x7e0 [epic100]
> > >  epic_close+0xec/0x2f0 [epic100]
> > >  unregister_netdev+0x18/0x20
> > >  epic_remove_one+0xaa/0xf0 [epic100]
> > >
> > > Fixes: ae150435b59e ("smsc: Move the SMC (SMSC) drivers")
> > > Reported-by: Yilun Wu <yiluwu@cs.stonybrook.edu>
> > > Signed-off-by: Tong Zhang <ztong0001@gmail.com>
> >
> > The "Fixes:" tag is a bit misleading: this code path predates the move
> > by several years. Ignoring pci_* vs dma_* API changes, this is pre-2005
> > material.
>
> Yeah, please find the correct Fixes tag.
>
> > Reviewed-by: Francois Romieu <romieu@fr.zoreil.com>
>
> Keep Francois' tag when reposting.

Looks like drivers/net/ethernet/smsc/epic100.c is renamed from
drivers/net/epic100.c
and this bug has been around since the very initial commit. What would
you suggest ?
Remove the fix tag or use
Fix: 1da177e4c3f4 ("Linux-2.6.12-rc2")