Re: [PATCH] vhost_net: initialize rx_ring in vhost_net_open()

On Thu, Mar 8, 2018 at 4:45 PM, Eric Dumazet [off-list ref] wrote:

On 03/08/2018 07:20 AM, Alexander Potapenko wrote:

quoted

On Thu, Mar 8, 2018 at 4:15 PM, Eric Dumazet [off-list ref]
wrote:

quoted

On 03/08/2018 05:37 AM, Alexander Potapenko wrote:

quoted

KMSAN reported a use of uninit memory in vhost_net_buf_unproduce()
while trying to access n->vqs[VHOST_NET_VQ_TX].rx_ring:


==================================================================

Signed-off-by: Alexander Potapenko <glider@google.com>

Please identify bug origin with a Fixes: tag

Fixes: 5990a30510ed1 ("tun/tap: use ptr_ring instead of skb_array")

Please send a V2 with this added tag. patchwork does not recognize it yet.

Ok, will do. Thanks for reminding about the tag!

David Miller has also a lot on his plate, please everybody be gentle with
both stable teams and maintainers.

Thanks.

quoted

The above patch introduced rx_ring, but the problem existed before.

quoted

This will tremendously help stable teams that are struggling with many
backports these days.

Thanks.

quoted

---
   drivers/vhost/net.c | 1 +
   1 file changed, 1 insertion(+)

diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index 610cba276d47..60f1080bffc7 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c

@@ -948,6 +948,7 @@ static int vhost_net_open(struct inode *inode,

struct
file *f)
                 n->vqs[i].done_idx = 0;
                 n->vqs[i].vhost_hlen = 0;
                 n->vqs[i].sock_hlen = 0;
+               n->vqs[i].rx_ring = NULL;
                 vhost_net_buf_init(&n->vqs[i].rxq);
         }
         vhost_dev_init(dev, vqs, VHOST_NET_VQ_MAX);

-- 
Alexander Potapenko
Software Engineer

Google Germany GmbH
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