FAILED: patch "[PATCH] RDMA/irdma: Fix kernel stack leak in irdma_create_user_ah()" failed to apply to 5.15-stable tree

The patch below does not apply to the 5.15-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y
git checkout FETCH_HEAD
git cherry-pick -x 74586c6da9ea222a61c98394f2fc0a604748438c
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2026030901-book-commodity-3938@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..

Possible dependencies:

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 74586c6da9ea222a61c98394f2fc0a604748438c Mon Sep 17 00:00:00 2001
From: Jason Gunthorpe <[email protected]>
Date: Mon, 16 Feb 2026 11:02:49 -0400
Subject: [PATCH] RDMA/irdma: Fix kernel stack leak in irdma_create_user_ah()

struct irdma_create_ah_resp {  // 8 bytes, no padding
    __u32 ah_id;               // offset 0 - SET (uresp.ah_id = ah->sc_ah.ah_info.ah_idx)
    __u8  rsvd[4];             // offset 4 - NEVER SET <- LEAK

};

rsvd[4]: 4 bytes of stack memory leaked unconditionally. Only ah_id is assigned before ib_respond_udata().

The reserved members of the structure were not zeroed.

index 15af53237217..7251cd7a2147 100644
@@ -5212,7 +5212,7 @@ static int irdma_create_user_ah(struct ib_ah *ibah,
 #define IRDMA_CREATE_AH_MIN_RESP_LEN offsetofend(struct irdma_create_ah_resp, rsvd)
 	struct irdma_ah *ah = container_of(ibah, struct irdma_ah, ibah);
 	struct irdma_device *iwdev = to_iwdev(ibah->pd->device);
-	struct irdma_create_ah_resp uresp;
+	struct irdma_create_ah_resp uresp = {};
 	struct irdma_ah *parent_ah;
 	int err;
 

From: Jason Gunthorpe <[email protected]>

[ Upstream commit 74586c6da9ea222a61c98394f2fc0a604748438c ]

struct irdma_create_ah_resp {  // 8 bytes, no padding
    __u32 ah_id;               // offset 0 - SET (uresp.ah_id = ah->sc_ah.ah_info.ah_idx)
    __u8  rsvd[4];             // offset 4 - NEVER SET <- LEAK

};

rsvd[4]: 4 bytes of stack memory leaked unconditionally. Only ah_id is assigned before ib_respond_udata().

The reserved members of the structure were not zeroed.

---
 drivers/infiniband/hw/irdma/verbs.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

index e62a825622834..40960f0803fbc 100644
@@ -4170,7 +4170,7 @@ static int irdma_create_ah(struct ib_ah *ibah,
 	struct irdma_sc_ah *sc_ah;
 	u32 ah_id = 0;
 	struct irdma_ah_info *ah_info;
-	struct irdma_create_ah_resp uresp;
+	struct irdma_create_ah_resp uresp = {};
 	union {
 		struct sockaddr saddr;
 		struct sockaddr_in saddr_in;

2.51.0