[PATCH] RDMA/ucma: fix rdma_ucm_query_ib_service_resp struct padding

From: Arnd Bergmann
Date: Mon Dec 08 2025 - 08:36:17 EST


From: Arnd Bergmann <arnd@xxxxxxxx>

On a few 32-bit architectures, the newly added ib_user_service_rec
structure is not 64-bit aligned the way it is on most regular ones.

Add explicit padding into the rdma_ucm_query_ib_service_resp and
rdma_ucm_resolve_ib_service structures that embed it, so that the
layout is compatible across all of them.

This is an ABI change on i386, aligning it with x86_64 and the other
64-bit architectures to avoid having to use a compat ioctl handler.

Fixes: 810f874eda8e ("RDMA/ucma: Support query resolved service records")
Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
---
include/uapi/rdma/rdma_user_cm.h | 2 ++
1 file changed, 2 insertions(+)

diff --git a/include/uapi/rdma/rdma_user_cm.h b/include/uapi/rdma/rdma_user_cm.h
index 5ded174687ee..8e1d584f6633 100644
--- a/include/uapi/rdma/rdma_user_cm.h
+++ b/include/uapi/rdma/rdma_user_cm.h
@@ -192,6 +192,7 @@ struct rdma_ucm_query_path_resp {

struct rdma_ucm_query_ib_service_resp {
__u32 num_service_recs;
+ __u32 :32;
struct ib_user_service_rec recs[];
};

@@ -362,6 +363,7 @@ struct rdma_ucm_ib_service {

struct rdma_ucm_resolve_ib_service {
__u32 id;
+ __u32 :32;
struct rdma_ucm_ib_service ibs;
};

--
2.39.5