From 5801c882fb64af9851e57aad709047e02726825b Mon Sep 17 00:00:00 2001
From: Jiasheng Jiang <jiashengjiangcool@gmail.com>
Date: Mon, 12 Jan 2026 01:54:12 +0000
Subject: [PATCH 2/8] RDMA/rxe: Fix double free in rxe_srq_from_init

commit 0beefd0e15d962f497aad750b2d5e9c3570b66d1 upstream.

In rxe_srq_from_init(), the queue pointer 'q' is assigned to
'srq->rq.queue' before copying the SRQ number to user space.
If copy_to_user() fails, the function calls rxe_queue_cleanup()
to free the queue, but leaves the now-invalid pointer in
'srq->rq.queue'.

The caller of rxe_srq_from_init() (rxe_create_srq) eventually
calls rxe_srq_cleanup() upon receiving the error, which triggers
a second rxe_queue_cleanup() on the same memory, leading to a
double free.

The call trace looks like this:
   kmem_cache_free+0x.../0x...
   rxe_queue_cleanup+0x1a/0x30 [rdma_rxe]
   rxe_srq_cleanup+0x42/0x60 [rdma_rxe]
   rxe_elem_release+0x31/0x70 [rdma_rxe]
   rxe_create_srq+0x12b/0x1a0 [rdma_rxe]
   ib_create_srq_user+0x9a/0x150 [ib_core]

Fix this by moving 'srq->rq.queue = q' after copy_to_user.

Fixes: aae0484e15f0 ("IB/rxe: avoid srq memory leak")
Signed-off-by: Jiasheng Jiang <jiashengjiangcool@gmail.com>
Link: https://patch.msgid.link/20260112015412.29458-1-jiashengjiangcool@gmail.com
Reviewed-by: Zhu Yanjun <yanjun.Zhu@linux.dev>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
[bwh: Backported to 6.1: There was no assignment to init->attr.max_wr
 here; don't add it]
Signed-off-by: Ben Hutchings <benh@debian.org>
---
 drivers/infiniband/sw/rxe/rxe_srq.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/infiniband/sw/rxe/rxe_srq.c b/drivers/infiniband/sw/rxe/rxe_srq.c
index 02b39498c370..038a9cd55413 100644
--- a/drivers/infiniband/sw/rxe/rxe_srq.c
+++ b/drivers/infiniband/sw/rxe/rxe_srq.c
@@ -69,8 +69,6 @@ int rxe_srq_from_init(struct rxe_dev *rxe, struct rxe_srq *srq,
 		return -ENOMEM;
 	}
 
-	srq->rq.queue = q;
-
 	err = do_mmap_info(rxe, uresp ? &uresp->mi : NULL, udata, q->buf,
 			   q->buf_size, &q->ip);
 	if (err) {
@@ -87,6 +85,8 @@ int rxe_srq_from_init(struct rxe_dev *rxe, struct rxe_srq *srq,
 		}
 	}
 
+	srq->rq.queue = q;
+
 	return 0;
 }
 
