linux-kernel - [PATCH v2 2/2] uacce: vma_close clears q->qfrs when freeing qfrs

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Message-Id: <20230511095921.9331-3-zhangfei.gao@linaro.org>
Date:   Thu, 11 May 2023 17:59:21 +0800
From:   Zhangfei Gao <zhangfei.gao@...aro.org>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Arnd Bergmann <arnd@...db.de>,
        Herbert Xu <herbert@...dor.apana.org.au>,
        jean-philippe <jean-philippe@...aro.org>,
        Wangzhou <wangzhou1@...ilicon.com>,
        Jonathan Cameron <Jonathan.Cameron@...wei.com>,
        Al Viro <viro@...iv.linux.org.uk>
Cc:     linux-kernel@...r.kernel.org, linux-crypto@...r.kernel.org,
        iommu@...ts.linux.dev, acc@...ts.linaro.org,
        Zhangfei Gao <zhangfei.gao@...aro.org>
Subject: [PATCH v2 2/2] uacce: vma_close clears q->qfrs when freeing qfrs

vma_close frees qfrs but not clears q->qfrs, which still points
to the freed object, leading to subsequent mmap fail.
So vma_close clears q->qfrs as well.

Suggested-by: Al Viro <viro@...iv.linux.org.uk>
Signed-off-by: Zhangfei Gao <zhangfei.gao@...aro.org>
---
 drivers/misc/uacce/uacce.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/drivers/misc/uacce/uacce.c b/drivers/misc/uacce/uacce.c
index 338b59ef5493..930c252753a0 100644
--- a/drivers/misc/uacce/uacce.c
+++ b/drivers/misc/uacce/uacce.c
@@ -200,12 +200,15 @@ static int uacce_fops_release(struct inode *inode, struct file *filep)
 static void uacce_vma_close(struct vm_area_struct *vma)
 {
 	struct uacce_queue *q = vma->vm_private_data;
-	struct uacce_qfile_region *qfr = NULL;
 
-	if (vma->vm_pgoff < UACCE_MAX_REGION)
-		qfr = q->qfrs[vma->vm_pgoff];
+	if (vma->vm_pgoff < UACCE_MAX_REGION) {
+		struct uacce_qfile_region *qfr = q->qfrs[vma->vm_pgoff];
 
-	kfree(qfr);
+		mutex_lock(&q->mutex);
+		q->qfrs[vma->vm_pgoff] = NULL;
+		mutex_unlock(&q->mutex);
+		kfree(qfr);
+	}
 }
 
 static const struct vm_operations_struct uacce_vm_ops = {
-- 
2.39.2 (Apple Git-143)