diff mbox series

[PULL,2/2] tests/virtio-9p-test: Don't call le*_to_cpus on fields of packed struct

Message ID 1490690794-19023-3-git-send-email-groug@kaod.org
State Accepted
Commit 34ef723ce34aaa14f94530c06a0ab3170a19bb59
Headers show
Series None | expand

Commit Message

Greg Kurz March 28, 2017, 8:46 a.m. UTC 
From: Peter Maydell <peter.maydell@linaro.org>


For a packed struct like 'P9Hdr' the fields within it may not be
aligned as much as the natural alignment for their types.  This means
it is not valid to pass the address of such a field to a function
like le32_to_cpus() which operate on uint32_t* and assume alignment.
Doing this results in a SIGBUS on hosts like SPARC which have strict
alignment requirements.

Use ldl_le_p() instead, which is specified to correctly handle
unaligned pointers.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

Reviewed-by: Greg Kurz <groug@kaod.org>

Signed-off-by: Greg Kurz <groug@kaod.org>

---
 tests/virtio-9p-test.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

-- 
2.7.4
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Patch

diff --git a/tests/virtio-9p-test.c b/tests/virtio-9p-test.c
index 43a1ad813fda..ad33d963876f 100644
--- a/tests/virtio-9p-test.c
+++ b/tests/virtio-9p-test.c
@@ -256,8 +256,8 @@  static void v9fs_req_recv(P9Req *req, uint8_t id)
         qvirtio_wait_queue_isr(v9p->dev, v9p->vq, 1000 * 1000);
 
         v9fs_memread(req, &hdr, 7);
-        le32_to_cpus(&hdr.size);
-        le16_to_cpus(&hdr.tag);
+        hdr.size = ldl_le_p(&hdr.size);
+        hdr.tag = lduw_le_p(&hdr.tag);
         if (hdr.size >= 7) {
             break;
         }