From: Stanislav Fomichev <sdf.kernel@gmail.com>
To: Jason Xing <kerneljasonxing@gmail.com>
Cc: davem@davemloft.net, edumazet@google.com, kuba@kernel.org,
pabeni@redhat.com, bjorn@kernel.org, magnus.karlsson@intel.com,
maciej.fijalkowski@intel.com, jonathan.lemon@gmail.com,
sdf@fomichev.me, ast@kernel.org, daniel@iogearbox.net,
hawk@kernel.org, john.fastabend@gmail.com, horms@kernel.org,
andrew+netdev@lunn.ch, bpf@vger.kernel.org,
netdev@vger.kernel.org, Jason Xing <kernelxing@tencent.com>
Subject: Re: [PATCH net 1/4] xsk: avoid skb leak in XDP_TX_METADATA case
Date: Mon, 20 Apr 2026 08:42:23 -0700 [thread overview]
Message-ID: <aeZI3ig6w0PhGaVU@devvm17672.vll0.facebook.com> (raw)
In-Reply-To: <aeZEjZSsVIdpcbFF@devvm17672.vll0.facebook.com>
On 04/20, Stanislav Fomichev wrote:
> On 04/18, Jason Xing wrote:
> > From: Jason Xing <kernelxing@tencent.com>
> >
> > Fix it by explicitly adding kfree_skb() before returning back to its
> > caller.
> >
> > How to reproduce it in virtio_net:
> > 1. the current skb is the first one (which means no frag and xs->skb is
> > NULL) and users enable metadata feature.
> > 2. xsk_skb_metadata() returns a error code.
> > 3. the caller xsk_build_skb() clears skb by using 'skb = NULL;'.
> > 4. there is no chance to free this skb anymore.
> >
> > Closes: https://lore.kernel.org/all/20260415085204.3F87AC19424@smtp.kernel.org/
> > Fixes: 30c3055f9c0d ("xsk: wrap generic metadata handling onto separate function")
> > Signed-off-by: Jason Xing <kernelxing@tencent.com>
>
> Acked-by: Stanislav Fomichev <sdf@fomichev.me>
Actually, I take that back.. While looking at patch 2 (which always
confuses me with that -EOVERFLOW handling), looks like we set
skb->destructor in xsk_skb_init_misc? So this kfree will do
xsk_cq_submit_addr_locked? Not sure that's what we want? Should we
move xsk_skb_init_misc to happen after xsk_skb_metadata?
next prev parent reply other threads:[~2026-04-20 15:42 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-04-18 4:56 [PATCH net 0/4] xsk: fix bugs around xsk skb allocation Jason Xing
2026-04-18 4:56 ` [PATCH net 1/4] xsk: avoid skb leak in XDP_TX_METADATA case Jason Xing
2026-04-20 15:22 ` Stanislav Fomichev
2026-04-20 15:42 ` Stanislav Fomichev [this message]
2026-04-20 16:27 ` Stanislav Fomichev
2026-04-21 0:55 ` Jason Xing
2026-04-18 4:56 ` [PATCH net 2/4] xsk: free the skb when hitting the upper bound MAX_SKB_FRAGS Jason Xing
2026-04-20 15:44 ` Stanislav Fomichev
2026-04-18 4:56 ` [PATCH net 3/4] xsk: handle NULL dereference of the skb without frags issue Jason Xing
2026-04-18 4:56 ` [PATCH net 4/4] xsk: fix use-after-free of xs->skb in xsk_build_skb() free_err path Jason Xing
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=aeZI3ig6w0PhGaVU@devvm17672.vll0.facebook.com \
--to=sdf.kernel@gmail.com \
--cc=andrew+netdev@lunn.ch \
--cc=ast@kernel.org \
--cc=bjorn@kernel.org \
--cc=bpf@vger.kernel.org \
--cc=daniel@iogearbox.net \
--cc=davem@davemloft.net \
--cc=edumazet@google.com \
--cc=hawk@kernel.org \
--cc=horms@kernel.org \
--cc=john.fastabend@gmail.com \
--cc=jonathan.lemon@gmail.com \
--cc=kerneljasonxing@gmail.com \
--cc=kernelxing@tencent.com \
--cc=kuba@kernel.org \
--cc=maciej.fijalkowski@intel.com \
--cc=magnus.karlsson@intel.com \
--cc=netdev@vger.kernel.org \
--cc=pabeni@redhat.com \
--cc=sdf@fomichev.me \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox