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[87.16.204.83]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-488fc18bccfsm396567715e9.8.2026.04.22.02.40.07 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 22 Apr 2026 02:40:08 -0700 (PDT) Date: Wed, 22 Apr 2026 11:40:00 +0200 From: Stefano Garzarella To: Dexuan Cui Cc: kys@microsoft.com, haiyangz@microsoft.com, wei.liu@kernel.org, longli@microsoft.com, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, horms@kernel.org, niuxuewei.nxw@antgroup.com, linux-hyperv@vger.kernel.org, virtualization@lists.linux.dev, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: Re: [PATCH net] hv_sock: Return -EIO for malformed/short packets Message-ID: References: <20260421174931.1152238-1-decui@microsoft.com> Precedence: bulk X-Mailing-List: linux-hyperv@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: <20260421174931.1152238-1-decui@microsoft.com> On Tue, Apr 21, 2026 at 10:49:31AM -0700, Dexuan Cui wrote: >Commit f63152958994 fixes a regression, however it fails to report an >error for malformed/short packets -- normally we should never see such >packets, but let's report an error for them just in case. > >Fixes: f63152958994 ("hv_sock: Report EOF instead of -EIO for FIN") >Cc: stable@vger.kernel.org >Signed-off-by: Dexuan Cui >--- > >Commit f63152958994 is currently only in net.git's master branch. > > net/vmw_vsock/hyperv_transport.c | 29 +++++++++++++++++++---------- > 1 file changed, 19 insertions(+), 10 deletions(-) > >diff --git a/net/vmw_vsock/hyperv_transport.c b/net/vmw_vsock/hyperv_transport.c >index 76e78c83fdbc..8faaa14bccda 100644 >--- a/net/vmw_vsock/hyperv_transport.c >+++ b/net/vmw_vsock/hyperv_transport.c >@@ -704,18 +704,27 @@ static s64 hvs_stream_has_data(struct vsock_sock *vsk) > if (hvs->recv_desc) { > /* Here hvs->recv_data_len is 0, so hvs->recv_desc must > * be NULL unless it points to the 0-byte-payload FIN >- * packet: see hvs_update_recv_data(). >+ * packet or a malformed/short packet: see >+ * hvs_update_recv_data(). > * >- * Here all the payload has been dequeued, but >- * hvs_channel_readable_payload() still returns 1, >- * because the VMBus ringbuffer's read_index is not >- * updated for the FIN packet: hvs_stream_dequeue() -> >- * hv_pkt_iter_next() updates the cached priv_read_index >- * but has no opportunity to update the read_index in >- * hv_pkt_iter_close() as hvs_stream_has_data() returns >- * 0 for the FIN packet, so it won't get dequeued. >+ * If hvs->recv_desc points to the FIN packet, here all >+ * the payload has been dequeued and the peer_shutdown >+ * flag is set, but hvs_channel_readable_payload() still >+ * returns 1, because the VMBus ringbuffer's read_index >+ * is not updated for the FIN packet: >+ * hvs_stream_dequeue() -> hv_pkt_iter_next() updates >+ * the cached priv_read_index but has no opportunity to >+ * update the read_index in hv_pkt_iter_close() as >+ * hvs_stream_has_data() returns 0 for the FIN packet, >+ * so it won't get dequeued. >+ * >+ * In case hvs->recv_desc points to a malformed/short >+ * packet, return -EIO. > */ >- return 0; >+ if (hvs->vsk->peer_shutdown & SEND_SHUTDOWN) We can access `vsk` directly, I mean `vsk->peer_shutdown`. >+ return 0; >+ else nit: we usually avoid the `else` if the other branch returns early, and maybe have the error returned first, so it's more clear when reading the comment on top. I mean something like this: if (!(vsk->peer_shutdown & SEND_SHUTDOWN)) return -EIO; return 0; BTW, not a strong opinion on that. The rest, LGTM! Thanks, Stefano