6.13-stable review patch. If anyone has any objections, please let me know.
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From: Wang Liang wangliang74@huawei.com
[ Upstream commit 5d0b204654de25615cf712be86c3192eca68ed80 ]
When the cq reservation is failed, the error code is not set which is initialized to zero in __xsk_generic_xmit(). That means the packet is not send successfully but sendto() return ok.
Considering the impact on uapi, return -EAGAIN is a good idea. The cq is full usually because it is not released in time, try to send msg again is appropriate.
The bug was at the very early implementation of xsk, so the Fixes tag targets the commit that introduced the changes in xsk_cq_reserve_addr_locked where this fix depends on.
Fixes: e6c4047f5122 ("xsk: Use xsk_buff_pool directly for cq functions") Suggested-by: Magnus Karlsson magnus.karlsson@gmail.com Signed-off-by: Wang Liang wangliang74@huawei.com Signed-off-by: Martin KaFai Lau martin.lau@kernel.org Acked-by: Stanislav Fomichev sdf@fomichev.me Link: https://patch.msgid.link/20250227081052.4096337-1-wangliang74@huawei.com Signed-off-by: Alexei Starovoitov ast@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- net/xdp/xsk.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c index 89d2bef964698..e04809a4c5d35 100644 --- a/net/xdp/xsk.c +++ b/net/xdp/xsk.c @@ -802,8 +802,11 @@ static int __xsk_generic_xmit(struct sock *sk) * if there is space in it. This avoids having to implement * any buffering in the Tx path. */ - if (xsk_cq_reserve_addr_locked(xs->pool, desc.addr)) + err = xsk_cq_reserve_addr_locked(xs->pool, desc.addr); + if (err) { + err = -EAGAIN; goto out; + }
skb = xsk_build_skb(xs, &desc); if (IS_ERR(skb)) {