From 290c4a902b79246ec55e477fc313f27f98393dee Mon Sep 17 00:00:00 2001 From: Bob Pearson Date: Sun, 10 Apr 2022 22:06:48 -0500 Subject: [PATCH] RDMA/rxe: Fix "Replace mr by rkey in responder resources" The referenced commit generates a reference counting error if the rkey has the same index but the wrong key. In this case the reference taken by rxe_pool_get_index() is not dropped. Drop the reference if the keys don't match in rxe_recheck_mr(). Check that the mw and mr are still valid. Fixes: 8a1a0be894da ("RDMA/rxe: Replace mr by rkey in responder resources") Link: https://lore.kernel.org/r/20220411030647.20011-1-rpearsonhpe@gmail.com Signed-off-by: Bob Pearson Signed-off-by: Jason Gunthorpe --- drivers/infiniband/sw/rxe/rxe_resp.c | 25 +++++++++++++++++-------- 1 file changed, 17 insertions(+), 8 deletions(-) diff --git a/drivers/infiniband/sw/rxe/rxe_resp.c b/drivers/infiniband/sw/rxe/rxe_resp.c index 16fc7ea1298d..1d95fab606da 100644 --- a/drivers/infiniband/sw/rxe/rxe_resp.c +++ b/drivers/infiniband/sw/rxe/rxe_resp.c @@ -680,6 +680,11 @@ static struct resp_res *rxe_prepare_read_res(struct rxe_qp *qp, * It is assumed that the access permissions if originally good * are OK and the mappings to be unchanged. * + * TODO: If someone reregisters an MR to change its size or + * access permissions during the processing of an RDMA read + * we should kill the responder resource and complete the + * operation with an error. + * * Return: mr on success else NULL */ static struct rxe_mr *rxe_recheck_mr(struct rxe_qp *qp, u32 rkey) @@ -690,23 +695,27 @@ static struct rxe_mr *rxe_recheck_mr(struct rxe_qp *qp, u32 rkey) if (rkey_is_mw(rkey)) { mw = rxe_pool_get_index(&rxe->mw_pool, rkey >> 8); - if (!mw || mw->rkey != rkey) + if (!mw) return NULL; - if (mw->state != RXE_MW_STATE_VALID) { + mr = mw->mr; + if (mw->rkey != rkey || mw->state != RXE_MW_STATE_VALID || + !mr || mr->state != RXE_MR_STATE_VALID) { rxe_put(mw); return NULL; } - mr = mw->mr; + rxe_get(mr); rxe_put(mw); - } else { - mr = rxe_pool_get_index(&rxe->mr_pool, rkey >> 8); - if (!mr || mr->rkey != rkey) - return NULL; + + return mr; } - if (mr->state != RXE_MR_STATE_VALID) { + mr = rxe_pool_get_index(&rxe->mr_pool, rkey >> 8); + if (!mr) + return NULL; + + if (mr->rkey != rkey || mr->state != RXE_MR_STATE_VALID) { rxe_put(mr); return NULL; }