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.mayd...@linaro.org> --- Sadly gcc doesn't warn about this: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=51628 clang supposedly was fixed to do so: https://bugs.llvm.org//show_bug.cgi?id=22821 but I think that commit was reverted without the bug being reopened; at least my clang doesn't have that warning flag. --- tests/virtio-9p-test.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/tests/virtio-9p-test.c b/tests/virtio-9p-test.c index 43a1ad8..ad33d96 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; } -- 2.7.4
