[PATCH] RDMA/rxe: Fix double free in rxe_srq_from_init

[Jiasheng Jiang]

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.

Fix this by setting 'srq->rq.queue' to NULL after the initial
cleanup in the error path.

Fixes: aae0484e15f0 ("IB/rxe: avoid srq memory leak")
Signed-off-by: Jiasheng Jiang <jiashengjiangcool@xxxxxxxxx>
---
 drivers/infiniband/sw/rxe/rxe_srq.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/infiniband/sw/rxe/rxe_srq.c b/drivers/infiniband/sw/rxe/rxe_srq.c
index 2a234f26ac10..c527c1cbd4ec 100644
--- a/drivers/infiniband/sw/rxe/rxe_srq.c
+++ b/drivers/infiniband/sw/rxe/rxe_srq.c
@@ -84,6 +84,7 @@ int rxe_srq_from_init(struct rxe_dev *rxe, struct rxe_srq *srq,
 		if (copy_to_user(&uresp->srq_num, &srq->srq_num,
 				 sizeof(uresp->srq_num))) {
 			rxe_queue_cleanup(q);
+			srq->rq.queue = NULL;
 			return -EFAULT;
 		}
 	}
-- 
2.25.1