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, 51 insertions, 0 deletions

diff --git a/tools/testing/nvdimm/pmem-dax.c b/tools/testing/nvdimm/pmem-dax.c
new file mode 100644
index 000000000..05e763aab
--- /dev/null
+++ b/tools/testing/nvdimm/pmem-dax.c
@@ -0,0 +1,51 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2014-2016, Intel Corporation.
+ */
+#include "test/nfit_test.h"
+#include <linux/blkdev.h>
+#include <linux/dax.h>
+#include <pmem.h>
+#include <nd.h>
+
+long __pmem_direct_access(struct pmem_device *pmem, pgoff_t pgoff,
+		long nr_pages, enum dax_access_mode mode, void **kaddr,
+		unsigned long *pfn)
+{
+	resource_size_t offset = PFN_PHYS(pgoff) + pmem->data_offset;
+
+	if (unlikely(is_bad_pmem(&pmem->bb, PFN_PHYS(pgoff) / 512,
+					PFN_PHYS(nr_pages))))
+		return -EIO;
+
+	/*
+	 * Limit dax to a single page at a time given vmalloc()-backed
+	 * in the nfit_test case.
+	 */
+	if (get_nfit_res(pmem->phys_addr + offset)) {
+		struct page *page;
+
+		if (kaddr)
+			*kaddr = pmem->virt_addr + offset;
+		page = vmalloc_to_page(pmem->virt_addr + offset);
+		if (pfn)
+			*pfn = page_to_pfn(page);
+		pr_debug_ratelimited("%s: pmem: %p pgoff: %#lx pfn: %#lx\n",
+				__func__, pmem, pgoff, page_to_pfn(page));
+
+		return 1;
+	}
+
+	if (kaddr)
+		*kaddr = pmem->virt_addr + offset;
+	if (pfn)
+		*pfn = PHYS_PFN(pmem->phys_addr + offset);
+
+	/*
+	 * If badblocks are present, limit known good range to the
+	 * requested range.
+	 */
+	if (unlikely(pmem->bb.count))
+		return nr_pages;
+	return PHYS_PFN(pmem->size - pmem->pfn_pad - offset);
+}