staging: ion: Prevent incorrect reference counting behavour

stable inclusion
from stable-v5.10.113
commit fea24b07edfc348c67a019b6e17b39c0698e631f
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I5ISAH

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=fea24b07edfc348c67a019b6e17b39c0698e631f

--------------------------------

Supply additional check in order to prevent unexpected results.

Fixes: b892bf75 ("ion: Switch ion to use dma-buf")
Suggested-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NLee Jones <lee.jones@linaro.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>
Acked-by: NXie XiuQi <xiexiuqi@huawei.com>

drivers/staging/android/ion/ion.c

@@ -114,6 +114,9 @@ static void *ion_buffer_kmap_get(struct ion_buffer *buffer)
 	void *vaddr;
 
 	if (buffer->kmap_cnt) {
+		if (buffer->kmap_cnt == INT_MAX)
+			return ERR_PTR(-EOVERFLOW);
+
 		buffer->kmap_cnt++;
 		return buffer->vaddr;
 	}