6.11-stable review patch. If anyone has any objections, please let me know.
------------------
From: Felix Maurer fmaurer@redhat.com
[ Upstream commit 0c0d0f42ffa6ac94cd79893b7ed419c15e1b45de ]
When a new skb is allocated for transmitting an xsk descriptor, i.e., for every non-multibuf descriptor or the first frag of a multibuf descriptor, but the descriptor is later found to have invalid options set for the TX metadata, the new skb is never freed. This can leak skbs until the send buffer is full which makes sending more packets impossible.
Fix this by freeing the skb in the error path if we are currently dealing with the first frag, i.e., an skb allocated in this iteration of xsk_build_skb.
Fixes: 48eb03dd2630 ("xsk: Add TX timestamp and TX checksum offload support") Reported-by: Michal Schmidt mschmidt@redhat.com Signed-off-by: Felix Maurer fmaurer@redhat.com Reviewed-by: Toke Høiland-Jørgensen toke@redhat.com Acked-by: Stanislav Fomichev sdf@fomichev.me Acked-by: Martin KaFai Lau martin.lau@kernel.org Link: https://patch.msgid.link/edb9b00fb19e680dff5a3350cd7581c5927975a8.1731581697... Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- net/xdp/xsk.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-)
diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c index 7e16336044b2d..6c042e03dad3c 100644 --- a/net/xdp/xsk.c +++ b/net/xdp/xsk.c @@ -675,6 +675,8 @@ static struct sk_buff *xsk_build_skb(struct xdp_sock *xs, len = desc->len;
if (!skb) { + first_frag = true; + hr = max(NET_SKB_PAD, L1_CACHE_ALIGN(dev->needed_headroom)); tr = dev->needed_tailroom; skb = sock_alloc_send_skb(&xs->sk, hr + len + tr, 1, &err); @@ -685,12 +687,8 @@ static struct sk_buff *xsk_build_skb(struct xdp_sock *xs, skb_put(skb, len);
err = skb_store_bits(skb, 0, buffer, len); - if (unlikely(err)) { - kfree_skb(skb); + if (unlikely(err)) goto free_err; - } - - first_frag = true; } else { int nr_frags = skb_shinfo(skb)->nr_frags; struct page *page; @@ -758,6 +756,9 @@ static struct sk_buff *xsk_build_skb(struct xdp_sock *xs, return skb;
free_err: + if (first_frag && skb) + kfree_skb(skb); + if (err == -EOVERFLOW) { /* Drop the packet */ xsk_set_destructor_arg(xs->skb);