From: Bob Pearson rpearsonhpe@gmail.com
[ 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@gmail.com Signed-off-by: Bob Pearson rpearsonhpe@gmail.com Signed-off-by: Jason Gunthorpe jgg@nvidia.com Signed-off-by: Sasha Levin sashal@kernel.org --- 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) {