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* [PATCH v2] vhost: fix compilation issue in async path
@ 2022-10-05 15:11 Maxime Coquelin
  2022-10-05 15:36 ` Maxime Coquelin
  2022-10-05 20:35 ` [PATCH v3] vhost: fix build issues with GCC 12 Maxime Coquelin
  0 siblings, 2 replies; 9+ messages in thread
From: Maxime Coquelin @ 2022-10-05 15:11 UTC (permalink / raw)
  To: dev, cheng1.jiang, chenbo.xia, zhoumin, david.marchand, thomas
  Cc: Maxime Coquelin, stable

This patch fixes a compilation issue met with GCC 12 on
LoongArch64:

In function ‘mbuf_to_desc’,
    inlined from ‘vhost_enqueue_async_packed’ at ../../../dpdk/lib/vhost/virtio_net.c:1822:6,
    inlined from ‘virtio_dev_rx_async_packed’ at ../../../dpdk/lib/vhost/virtio_net.c:1836:6,
    inlined from ‘virtio_dev_rx_async_submit_packed’ at ../../../dpdk/lib/vhost/virtio_net.c:1895:7:
../../../dpdk/lib/vhost/virtio_net.c:1159:18: error: ‘buf_vec[0].buf_addr’ may be used uninitialized [-Werror=maybe-uninitialized]
 1159 |         buf_addr = buf_vec[vec_idx].buf_addr;
      |         ~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~
../../../dpdk/lib/vhost/virtio_net.c: In function ‘virtio_dev_rx_async_submit_packed’:
../../../dpdk/lib/vhost/virtio_net.c:1834:27: note: ‘buf_vec’ declared here
 1834 |         struct buf_vector buf_vec[BUF_VECTOR_MAX];
      |                           ^~~~~~~

It happens because the compiler assumes that 'size'
variable in vhost_enqueue_async_packed could wrap to 0 since
'size' is uint32_t and pkt->pkt_len too.

In practice, it would never happen since 'pkt->pkt_len' is
unlikely to be close to UINT32_MAX, but let's just change
'size' to uint64_t to make the compiler happy without
having to add runtime checks.

Fixes: 873e8dad6f49 ("vhost: support packed ring in async datapath")
Cc: stable@dpdk.org

Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
---
 lib/vhost/virtio_net.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/vhost/virtio_net.c b/lib/vhost/virtio_net.c
index 8f4d0f0502..b86fb26040 100644
--- a/lib/vhost/virtio_net.c
+++ b/lib/vhost/virtio_net.c
@@ -1780,7 +1780,7 @@ vhost_enqueue_async_packed(struct virtio_net *dev,
 	uint16_t buf_id = 0;
 	uint32_t len = 0;
 	uint16_t desc_count = 0;
-	uint32_t size = pkt->pkt_len + sizeof(struct virtio_net_hdr_mrg_rxbuf);
+	uint64_t size = pkt->pkt_len + sizeof(struct virtio_net_hdr_mrg_rxbuf);
 	uint32_t buffer_len[vq->size];
 	uint16_t buffer_buf_id[vq->size];
 	uint16_t buffer_desc_count[vq->size];
-- 
2.37.3


^ permalink raw reply	[flat|nested] 9+ messages in thread
end of thread, other threads:[~2022-10-06 10:21 UTC | newest]

Thread overview: 9+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-10-05 15:11 [PATCH v2] vhost: fix compilation issue in async path Maxime Coquelin
2022-10-05 15:36 ` Maxime Coquelin
2022-10-05 16:34   ` David Marchand
2022-10-05 20:35 ` [PATCH v3] vhost: fix build issues with GCC 12 Maxime Coquelin
2022-10-06  0:01   ` Stephen Hemminger
2022-10-06  7:51     ` Maxime Coquelin
2022-10-06  8:22       ` [EXT] " Amit Prakash Shukla
2022-10-06  9:05         ` Maxime Coquelin
2022-10-06 10:21   ` Thomas Monjalon

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