aio: nullify aio->ring_pages after freeing it

commit ddb8c45ba15149ebd41d7586261c05f7ca37f9a1 upstream.

After freeing ring_pages we leave it as is causing a dangling pointer. This
has already caused an issue so to help catching any issues in the future
NULL it out.

Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Benjamin LaHaise <bcrl@kvack.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/aio.c b/fs/aio.c
index f4103b3..08159ed 100644 (file)
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -251,8 +251,10 @@ static void aio_free_ring(struct kioctx *ctx)
 
        put_aio_ring_file(ctx);
 
-       if (ctx->ring_pages && ctx->ring_pages != ctx->internal_pages)
+       if (ctx->ring_pages && ctx->ring_pages != ctx->internal_pages) {
                kfree(ctx->ring_pages);
+               ctx->ring_pages = NULL;
+       }
 }
 
 static int aio_ring_mmap(struct file *file, struct vm_area_struct *vma)