From: Lee Jones <lee.jones@linaro.org>
Date: Mon, 25 Apr 2022 15:51:54 +0000 (+0100)
Subject: staging: ion: Prevent incorrect reference counting behavour
X-Git-Tag: v5.10.113~3
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=fea24b07edfc348c67a019b6e17b39c0698e631f;p=thirdparty%2Fkernel%2Fstable.git

staging: ion: Prevent incorrect reference counting behavour

Supply additional check in order to prevent unexpected results.

Fixes: b892bf75b2034 ("ion: Switch ion to use dma-buf")
Suggested-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/staging/android/ion/ion.c b/drivers/staging/android/ion/ion.c
index e1fe03ceb7f13..e6d4a3ee6cda5 100644
--- a/drivers/staging/android/ion/ion.c
+++ b/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;
 	}