[PATCH 5.10 84/86] staging: ion: Prevent incorrect reference counting behavour

Greg Kroah-Hartman
2022-04-26T08:58:39Z

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>
---
drivers/staging/android/ion/ion.c | 3 +++
1 file changed, 3 insertions(+)

--- 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
void *vaddr;

if (buffer->kmap_cnt) {
+ if (buffer->kmap_cnt == INT_MAX)
+ return ERR_PTR(-EOVERFLOW);
+
buffer->kmap_cnt++;
return buffer->vaddr;
}