diff --git a/run-command.c b/run-command.c
index 5fbaa8b5ac..5ec3a46dcc 100644
--- a/run-command.c
+++ b/run-command.c
@@ -10,6 +10,7 @@
 #include "config.h"
 #include "packfile.h"
 #include "hook.h"
+#include "compat/nonblock.h"
 
 void child_process_init(struct child_process *child)
 {
@@ -1451,6 +1452,15 @@ int pipe_command(struct child_process *cmd,
 		return -1;
 
 	if (in) {
+		if (enable_pipe_nonblock(cmd->in) < 0) {
+			error_errno("unable to make pipe non-blocking");
+			close(cmd->in);
+			if (out)
+				close(cmd->out);
+			if (err)
+				close(cmd->err);
+			return -1;
+		}
 		io[nr].fd = cmd->in;
 		io[nr].type = POLLOUT;
 		io[nr].u.out.buf = in;
diff --git a/t/t3701-add-interactive.sh b/t/t3701-add-interactive.sh
index b354fb39de..3b7df9bed5 100755
--- a/t/t3701-add-interactive.sh
+++ b/t/t3701-add-interactive.sh
@@ -766,6 +766,19 @@ test_expect_success 'detect bogus diffFilter output' '
 	force_color test_must_fail git add -p <y
 '
 
+test_expect_success 'handle very large filtered diff' '
+	git reset --hard &&
+	# The specific number here is not important, but it must
+	# be large enough that the output of "git diff --color"
+	# fills up the pipe buffer. 10,000 results in ~200k of
+	# colored output.
+	test_seq 10000 >test &&
+	test_config interactive.diffFilter cat &&
+	printf y >y &&
+	force_color git add -p >output 2>&1 <y &&
+	git diff-files --exit-code -- test
+'
+
 test_expect_success 'diff.algorithm is passed to `git diff-files`' '
 	git reset --hard &&