Fix kfifo_out return value check

This fixes commit 24ba4efd42fe ("Check return value of kfifo_out") which
exposes a bug in the bluetooth HAL that causes a SIGABRT due to an
uncaught exception from trying to parse a negative number using stoul.
This SIGABRT crashes the bluetooth HAL. So to workaround this, instead
of returning an error, return 0 on error which is what happens if this
procfs file doesn't exist.

Fixes: 24ba4efd42fe ("Check return value of kfifo_out")
Bug: 230397443
Signed-off-by: Will McVicker <willmcvicker@google.com>
Change-Id: I8058a32985b6e7d5d38e216ee1032c8178edd4b3

1 files changed, 2 insertions, 4 deletions

diff --git a/nitrous.c b/nitrous.c
index d49ae60..f311035 100644
--- a/nitrous.c
+++ b/nitrous.c
@@ -266,10 +266,8 @@ static int nitrous_proc_show(struct seq_file *m, void *v)
 		break;
 	case PROC_TIMESYNC:
 		ret = kfifo_out(&lpm->timestamp_queue, &timestamp, sizeof(ktime_t));
-		if (ret != sizeof(ktime_t)) {
-			dev_err(lpm->dev, "failed to get the timestamp, ret=%u\n", ret);
-			return -EINVAL;
-		}
+		if (ret != sizeof(ktime_t))
+			timestamp = 0;
 		seq_printf(m, "%lld", ktime_to_us(timestamp));
 		break;
 	default: