[PATCH 10/10] thread_with_stdio: suppress hung task warning

["Darrick J. Wong" <djwong@xxxxxxxxxx>]

From: Kent Overstreet <kent.overstreet@xxxxxxxxx>

Signed-off-by: Kent Overstreet <kent.overstreet@xxxxxxxxx>
Reviewed-by: Darrick J. Wong <djwong@xxxxxxxxxx>
Signed-off-by: Darrick J. Wong <djwong@xxxxxxxxxx>
---
 lib/thread_with_file.c |   17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)


diff --git a/lib/thread_with_file.c b/lib/thread_with_file.c
index f4946a437332a..b09dc60ba6280 100644
--- a/lib/thread_with_file.c
+++ b/lib/thread_with_file.c
@@ -9,6 +9,7 @@
 #include <linux/module.h>
 #include <linux/pagemap.h>
 #include <linux/poll.h>
+#include <linux/sched/sysctl.h>
 #include <linux/thread_with_file.h>
 
 /* stdio_redirect */
@@ -46,7 +47,15 @@ int stdio_redirect_read(struct stdio_redirect *stdio, char *ubuf, size_t len)
 {
 	struct stdio_buf *buf = &stdio->input;
 
-	wait_event(buf->wait, stdio_redirect_has_input(stdio));
+	/*
+	 * we're waiting on user input (or for the file descriptor to be
+	 * closed), don't want a hung task warning:
+	 */
+	do {
+		wait_event_timeout(buf->wait, stdio_redirect_has_input(stdio),
+				   sysctl_hung_task_timeout_secs * HZ / 2);
+	} while (!stdio_redirect_has_input(stdio));
+
 	if (stdio->done)
 		return -1;
 
@@ -67,7 +76,11 @@ int stdio_redirect_readline(struct stdio_redirect *stdio, char *ubuf, size_t len
 	size_t copied = 0;
 	ssize_t ret = 0;
 again:
-	wait_event(buf->wait, stdio_redirect_has_input(stdio));
+	do {
+		wait_event_timeout(buf->wait, stdio_redirect_has_input(stdio),
+				   sysctl_hung_task_timeout_secs * HZ / 2);
+	} while (!stdio_redirect_has_input(stdio));
+
 	if (stdio->done) {
 		ret = -1;
 		goto out;