diff mbox series

[v1,3/3] kselftest/arm64: Handle EINTR while reading data from children

Message ID 20220921181345.618085-4-broonie@kernel.org (mailing list archive)
State Accepted
Commit a711987490a1784c3e3fd6d752a63501c11eb80b
Headers show
Series kselftest/arm64: fp-stress updates | expand

Commit Message

Mark Brown Sept. 21, 2022, 6:13 p.m. UTC
Currently we treat any error when reading from the child as a failure and
don't read any more output from that child as a result. This ignores the
fact that it is valid for read() to return EINTR as the error code if there
is a signal pending so we could stop handling the output of children,
especially during exit when we will get some SIGCHLD signals delivered to
us. Fix this by pulling the read handling out into a separate function
which returns a flag if reads should be continued and wrapping it in a
loop.

Signed-off-by: Mark Brown <broonie@kernel.org>
---
 tools/testing/selftests/arm64/fp/fp-stress.c | 85 ++++++++++++--------
 1 file changed, 50 insertions(+), 35 deletions(-)
diff mbox series

Patch

diff --git a/tools/testing/selftests/arm64/fp/fp-stress.c b/tools/testing/selftests/arm64/fp/fp-stress.c
index 03ce3936220a..4e62a9199f97 100644
--- a/tools/testing/selftests/arm64/fp/fp-stress.c
+++ b/tools/testing/selftests/arm64/fp/fp-stress.c
@@ -121,55 +121,70 @@  static void child_start(struct child_data *child, const char *program)
 	}
 }
 
-static void child_output(struct child_data *child, uint32_t events,
-			 bool flush)
+static bool child_output_read(struct child_data *child)
 {
 	char read_data[1024];
 	char work[1024];
 	int ret, len, cur_work, cur_read;
 
-	if (events & EPOLLIN) {
-		ret = read(child->stdout, read_data, sizeof(read_data));
-		if (ret < 0) {
-			ksft_print_msg("%s: read() failed: %s (%d)\n",
-				       child->name, strerror(errno), errno);
-			return;
-		}
-		len = ret;
+	ret = read(child->stdout, read_data, sizeof(read_data));
+	if (ret < 0) {
+		if (errno == EINTR)
+			return true;
 
-		child->output_seen = true;
+		ksft_print_msg("%s: read() failed: %s (%d)\n",
+			       child->name, strerror(errno),
+			       errno);
+		return false;
+	}
+	len = ret;
 
-		/* Pick up any partial read */
-		if (child->output) {
-			strncpy(work, child->output, sizeof(work) - 1);
-			cur_work = strnlen(work, sizeof(work));
-			free(child->output);
-			child->output = NULL;
-		} else {
-			cur_work = 0;
-		}
+	child->output_seen = true;
 
-		cur_read = 0;
-		while (cur_read < len) {
-			work[cur_work] = read_data[cur_read++];
+	/* Pick up any partial read */
+	if (child->output) {
+		strncpy(work, child->output, sizeof(work) - 1);
+		cur_work = strnlen(work, sizeof(work));
+		free(child->output);
+		child->output = NULL;
+	} else {
+		cur_work = 0;
+	}
 
-			if (work[cur_work] == '\n') {
-				work[cur_work] = '\0';
-				ksft_print_msg("%s: %s\n", child->name, work);
-				cur_work = 0;
-			} else {
-				cur_work++;
-			}
-		}
+	cur_read = 0;
+	while (cur_read < len) {
+		work[cur_work] = read_data[cur_read++];
 
-		if (cur_work) {
+		if (work[cur_work] == '\n') {
 			work[cur_work] = '\0';
-			ret = asprintf(&child->output, "%s", work);
-			if (ret == -1)
-				ksft_exit_fail_msg("Out of memory\n");
+			ksft_print_msg("%s: %s\n", child->name, work);
+			cur_work = 0;
+		} else {
+			cur_work++;
 		}
 	}
 
+	if (cur_work) {
+		work[cur_work] = '\0';
+		ret = asprintf(&child->output, "%s", work);
+		if (ret == -1)
+			ksft_exit_fail_msg("Out of memory\n");
+	}
+
+	return false;
+}
+
+static void child_output(struct child_data *child, uint32_t events,
+			 bool flush)
+{
+	bool read_more;
+
+	if (events & EPOLLIN) {
+		do {
+			read_more = child_output_read(child);
+		} while (read_more);
+	}
+
 	if (events & EPOLLHUP) {
 		close(child->stdout);
 		child->stdout = -1;