IB/rxe: don't crash, if allocation of crc algorithm failed

Following crash happens, if crc algorithm couldn't be allocated:

[ 1087.989072] rdma_rxe: loaded
[ 1097.855397] PCLMULQDQ-NI instructions are not detected.
[ 1097.901220] rdma_rxe: failed to allocate crc algorithmi err:-2
[ 1097.901248] BUG: unable to handle kernel
[ 1097.901249] NULL pointer dereference
[ 1097.901250]  at 0000000000000046
[...]

Reason is that rxe->tfm is assigned the error return, which will then
be used for crypto_free_shash() in rxe_cleanup. Fix by using a
temporary variable and assigning it rxe->tfm after allocation succeeded.

Fixes: cee2688e3cd6 ("IB/rxe: Offload CRC calculation when possible")
Signed-off-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
Reviewed-by: Leon Romanovsky <leonro@mellanox.com>
Acked-by: Moni Shoua <monis@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

diff --git a/drivers/infiniband/sw/rxe/rxe_verbs.c b/drivers/infiniband/sw/rxe/rxe_verbs.c
index ff77f4f..d03002b 100644 (file)
--- a/drivers/infiniband/sw/rxe/rxe_verbs.c
+++ b/drivers/infiniband/sw/rxe/rxe_verbs.c
@@ -1192,6 +1192,7 @@ int rxe_register_device(struct rxe_dev *rxe)
        int err;
        int i;
        struct ib_device *dev = &rxe->ib_dev;
+       struct crypto_shash *tfm;
 
        strlcpy(dev->name, "rxe%d", IB_DEVICE_NAME_MAX);
        strlcpy(dev->node_desc, "rxe", sizeof(dev->node_desc));
@@ -1289,12 +1290,13 @@ int rxe_register_device(struct rxe_dev *rxe)
        dev->get_hw_stats = rxe_ib_get_hw_stats;
        dev->alloc_hw_stats = rxe_ib_alloc_hw_stats;
 
-       rxe->tfm = crypto_alloc_shash("crc32", 0, 0);
-       if (IS_ERR(rxe->tfm)) {
+       tfm = crypto_alloc_shash("crc32", 0, 0);
+       if (IS_ERR(tfm)) {
                pr_err("failed to allocate crc algorithm err:%ld\n",
-                      PTR_ERR(rxe->tfm));
-               return PTR_ERR(rxe->tfm);
+                      PTR_ERR(tfm));
+               return PTR_ERR(tfm);
        }
+       rxe->tfm = tfm;
 
        err = ib_register_device(dev, NULL);
        if (err) {