drm/mediatek: Add missing IS_ERR check for ovl_adaptor platform devicegrafted

platform_device_register_data() can fail and return an ERR_PTR, but the
return value is used without checking, leading to an invalid pointer
being stored in ddp_comp[].dev and passed to component_match_add() and
mtk_ddp_comp_init(), which could result in a kernel crash.

Add an IS_ERR() check to jump to the error handling path on failure.

Fixes: 0d9eee9118b7 ("drm/mediatek: Add drm ovl_adaptor sub driver for MT8195")
Cc: stable@vger.kernel.org
Signed-off-by: Haojie Li <lihaojie@kylinos.cn>
Reviewed-by: CK Hu <ck.hu@mediatek.com>
Link: https://patchwork.kernel.org/project/linux-mediatek/patch/20260825100845.438893-1-lihaojie@kylinos.cn/
Signed-off-by: Chun-Kuang Hu <chunkuang.hu@kernel.org>

1 files changed, 104 insertions, 0 deletions

diff --git a/tools/thermal/lib/mainloop.c b/tools/thermal/lib/mainloop.c
new file mode 100644
index 000000000..bf4c1b730
--- /dev/null
+++ b/tools/thermal/lib/mainloop.c
@@ -0,0 +1,104 @@
+// SPDX-License-Identifier: LGPL-2.1+
+// Copyright (C) 2022, Linaro Ltd - Daniel Lezcano <daniel.lezcano@linaro.org>
+#include <stdlib.h>
+#include <errno.h>
+#include <unistd.h>
+#include <signal.h>
+#include <sys/epoll.h>
+#include "mainloop.h"
+#include "log.h"
+
+static int epfd = -1;
+static sig_atomic_t exit_mainloop;
+
+struct mainloop_data {
+	mainloop_callback_t cb;
+	void *data;
+	int fd;
+};
+
+#define MAX_EVENTS 10
+
+int mainloop(unsigned int timeout)
+{
+	int i, nfds;
+	struct epoll_event events[MAX_EVENTS];
+	struct mainloop_data *md;
+
+	if (epfd < 0)
+		return -1;
+
+	for (;;) {
+
+		nfds = epoll_wait(epfd, events, MAX_EVENTS, timeout);
+
+		if (exit_mainloop || !nfds)
+			return 0;
+
+		if (nfds < 0) {
+			if (errno == EINTR)
+				continue;
+			return -1;
+		}
+
+		for (i = 0; i < nfds; i++) {
+			md = events[i].data.ptr;
+
+			if (md->cb(md->fd, md->data) > 0)
+				return 0;
+		}
+	}
+}
+
+int mainloop_add(int fd, mainloop_callback_t cb, void *data)
+{
+	struct epoll_event ev = {
+		.events = EPOLLIN,
+	};
+
+	struct mainloop_data *md;
+
+	md = malloc(sizeof(*md));
+	if (!md)
+		return -1;
+
+	md->data = data;
+	md->cb = cb;
+	md->fd = fd;
+
+	ev.data.ptr = md;
+
+	if (epoll_ctl(epfd, EPOLL_CTL_ADD, fd, &ev) < 0) {
+		free(md);
+		return -1;
+	}
+
+	return 0;
+}
+
+int mainloop_del(int fd)
+{
+	if (epoll_ctl(epfd, EPOLL_CTL_DEL, fd, NULL) < 0)
+		return -1;
+
+	return 0;
+}
+
+int mainloop_init(void)
+{
+	epfd = epoll_create(2);
+	if (epfd < 0)
+		return -1;
+
+	return 0;
+}
+
+void mainloop_exit(void)
+{
+	exit_mainloop = 1;
+}
+
+void mainloop_fini(void)
+{
+	close(epfd);
+}