[PATCH AUTOSEL 6.18] RDMA/irdma: Fix double free related to rereg_user_mr

[PATCH AUTOSEL 6.18] RDMA/irdma: Fix double free related to rereg_user_mr

[Sasha Levin]

From: Jacob Moroni <jmoroni@google.com>

[ Upstream commit 29a3edd7004bb635d299fb9bc6f0ea4ef13ed5a2 ]

If IB_MR_REREG_TRANS is set during rereg_user_mr, the
umem will be released and a new one will be allocated
in irdma_rereg_mr_trans. If any step of irdma_rereg_mr_trans
fails after the new umem is allocated, it releases the umem,
but does not set iwmr->region to NULL. The problem is that
this failure is propagated to the user, who will then call
ibv_dereg_mr (as they should). Then, the dereg_mr path will
see a non-NULL umem and attempt to call ib_umem_release again.

Fix this by setting iwmr->region to NULL after ib_umem_release.

Fixed: 5ac388db27c4 ("RDMA/irdma: Add support to re-register a memory region")
Signed-off-by: Jacob Moroni <jmoroni@google.com>
Link: https://patch.msgid.link/20260227152743.1183388-1-jmoroni@google.com
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---

LLM Generated explanations, may be completely bogus:

Error: Failed to generate final synthesis

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

diff --git a/drivers/infiniband/hw/irdma/verbs.c b/drivers/infiniband/hw/irdma/verbs.c
index c77d6d0eafdec..c399aa07bcae8 100644
--- a/drivers/infiniband/hw/irdma/verbs.c
+++ b/drivers/infiniband/hw/irdma/verbs.c
@@ -3714,6 +3714,7 @@ static int irdma_rereg_mr_trans(struct irdma_mr *iwmr, u64 start, u64 len,
 
 err:
 	ib_umem_release(region);
+	iwmr->region = NULL;
 	return err;
 }
 
-- 
2.53.0