Re: [PATCH net 2/2] vsock/test: add MSG_PEEK after partial recv test

[Luigi Leonardi]

Hi Arseniy,

On Sun, Apr 05, 2026 at 10:14:26PM +0300, Arseniy Krasnov wrote:
> 02.04.2026 11:18, Luigi Leonardi wrote:
> > Add a test that verifies MSG_PEEK works correctly after a partial
> > recv().
> >
> > This is to test a bug that was present in the `virtio_transport_stream_do_peek()`
> > when computing the number of bytes to copy: After a partial read, the
> > peek function didn't take into consideration the number of bytes that
> > were already read. So peeking the whole buffer would cause a out-of-bounds read,
> > that resulted in a -EFAULT.
> >
> > This test does exactly this: do a partial recv on a buffer, then try to
> > peek the whole buffer content.
> >
> > Signed-off-by: Luigi Leonardi <leonardi@xxxxxxxxxx>
> > ---
> >  tools/testing/vsock/vsock_test.c | 64 ++++++++++++++++++++++++++++++++++++++++
> >  1 file changed, 64 insertions(+)
> >
> > diff --git a/tools/testing/vsock/vsock_test.c b/tools/testing/vsock/vsock_test.c
> > index 5bd20ccd9335caafe68e8b7a5d02a4deb3d2deec..308f9f8f30d22bec5aaa282356e400d8438fe321 100644
> > --- a/tools/testing/vsock/vsock_test.c
> > +++ b/tools/testing/vsock/vsock_test.c
> > @@ -346,6 +346,65 @@ static void test_stream_msg_peek_server(const struct test_opts *opts)
> >  	return test_msg_peek_server(opts, false);
> >  }
> >
> > +#define PEEK_AFTER_RECV_LEN 100
>
> Hi, may be we can just reuse MSG_PEEK_BUF_LEN which was already used in MSG_PEEK tests ?

yep, good idea!

Thanks!