cxgb4:Fix out-of-bounds MSI-X info array access

[ Upstream commit 6b517374 ]

When fetching free MSI-X vectors for ULDs, check for the error code
before accessing MSI-X info array. Otherwise, an out-of-bounds access is
attempted, which results in kernel panic.

Fixes: 94cdb8bb ("cxgb4: Add support for dynamic allocation of resources for ULD")
Signed-off-by: Shahjada Abul Husain <shahjada@chelsio.com>
Signed-off-by: Vishal Kulkarni <vishal@chelsio.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/net/ethernet/chelsio/cxgb4/cxgb4_uld.c

@@ -137,13 +137,12 @@ static int uldrx_handler(struct sge_rspq *q, const __be64 *rsp,
 static int alloc_uld_rxqs(struct adapter *adap,
 			  struct sge_uld_rxq_info *rxq_info, bool lro)
 {
-	struct sge *s = &adap->sge;
 	unsigned int nq = rxq_info->nrxq + rxq_info->nciq;
+	int i, err, msi_idx, que_idx = 0, bmap_idx = 0;
 	struct sge_ofld_rxq *q = rxq_info->uldrxq;
 	unsigned short *ids = rxq_info->rspq_id;
-	unsigned int bmap_idx = 0;
+	struct sge *s = &adap->sge;
 	unsigned int per_chan;
-	int i, err, msi_idx, que_idx = 0;
 
 	per_chan = rxq_info->nrxq / adap->params.nports;
 
@@ -161,6 +160,10 @@ static int alloc_uld_rxqs(struct adapter *adap,
 
 		if (msi_idx >= 0) {
 			bmap_idx = get_msix_idx_from_bmap(adap);
+			if (bmap_idx < 0) {
+				err = -ENOSPC;
+				goto freeout;
+			}
 			msi_idx = adap->msix_info_ulds[bmap_idx].idx;
 		}
 		err = t4_sge_alloc_rxq(adap, &q->rspq, false,