From: Bob Pearson <rpearsonhpe@xxxxxxxxx>
[ Upstream commit b00683422fd79dd07c9b75efdce1660e5e19150e ]
There is a reference count error in error path code and a potential race
in check_rkey() in rxe_resp.c. When looking up the rkey for a memory
window the reference to the mw from rxe_lookup_mw() is dropped before a
reference is taken on the mr referenced by the mw. If the mr is destroyed
immediately after the call to rxe_put(mw) the mr pointer is unprotected
and may end up pointing at freed memory. The rxe_get(mr) call should take
place before the rxe_put(mw) call.
All errors in check_rkey() call rxe_put(mw) if mw is not NULL but it was
already called after the above. The mw pointer should be set to NULL after
the rxe_put(mw) call to prevent this from happening.
Fixes: cdd0b85675ae ("RDMA/rxe: Implement memory access through MWs")
Link: https://lore.kernel.org/r/20230517211509.1819998-1-rpearsonhpe@xxxxxxxxx
Signed-off-by: Bob Pearson <rpearsonhpe@xxxxxxxxx>
Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/infiniband/sw/rxe/rxe_resp.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/infiniband/sw/rxe/rxe_resp.c b/drivers/infiniband/sw/rxe/rxe_resp.c
index 8c68340502769..4e8d8bec0010b 100644
--- a/drivers/infiniband/sw/rxe/rxe_resp.c
+++ b/drivers/infiniband/sw/rxe/rxe_resp.c
@@ -519,8 +519,9 @@ static enum resp_states check_rkey(struct rxe_qp *qp,
if (mw->access & IB_ZERO_BASED)
qp->resp.offset = mw->addr;
- rxe_put(mw);
rxe_get(mr);
+ rxe_put(mw);
+ mw = NULL;
} else {
mr = lookup_mr(qp->pd, access, rkey, RXE_LOOKUP_REMOTE);
if (!mr) {
--
2.39.2
