ASoC: Add backend user count checking

Add backend user count checking to protect the index
boundary.

Bug: 33751424
Change-Id: Ic1b61d1f7130252cc54da0b16553858714988dbd
CRs-Fixed: 2009216
Signed-off-by: Walter Yang <yandongy@codeaurora.org>
Signed-off-by: Siqi Lin <siqilin@google.com>

sound/soc/soc-compress.c

@@ -531,6 +531,11 @@ static int soc_compr_set_params_fe(struct snd_compr_stream *cstream,
 				cstream, &async_domain);
 			} else {
 				be_list[j++] = be;
+				if (j == DPCM_MAX_BE_USERS) {
+					dev_dbg(fe->dev,
+						"ASoC: MAX backend users!\n");
+					break;
+				}
 			}
 		}
 		for (i = 0; i < j; i++) {

sound/soc/soc-pcm.c

@@ -2320,6 +2320,10 @@ void dpcm_be_dai_prepare_async(struct snd_soc_pcm_runtime *fe, int stream,
 							    dpcm, domain);
 		} else {
 			dpcm_async[i++] = dpcm;
+			if (i == DPCM_MAX_BE_USERS) {
+				dev_dbg(fe->dev, "ASoC: MAX backend users!\n");
+				break;
+			}
 		}
 	}