udmabuf: fix a buf size overflow issue during udmabuf creation

[ Upstream commit 021ba7f ]

by casting size_limit_mb to u64  when calculate pglimit.

Signed-off-by: Xiaogang Chen<Xiaogang.Chen@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20250321164126.329638-1-xiaogang.chen@amd.com
Signed-off-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Amelia Crate <acrate@waldn.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: xiaogang-chen-amd

drivers/dma-buf/udmabuf.c

@@ -350,7 +350,7 @@ static long udmabuf_create(struct miscdevice *device,
 		return -ENOMEM;
 
 	INIT_LIST_HEAD(&ubuf->unpin_list);
-	pglimit = (size_limit_mb * 1024 * 1024) >> PAGE_SHIFT;
+	pglimit = ((u64)size_limit_mb * 1024 * 1024) >> PAGE_SHIFT;
 	for (i = 0; i < head->count; i++) {
 		if (!PAGE_ALIGNED(list[i].offset))
 			goto err;