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From: Sukrut Bellary <sukrut.bellary@linux.com>
To: "Jeffrey Hugo" <quic_jhugo@quicinc.com>,
	"Oded Gabbay" <ogabbay@kernel.org>,
	"Sumit Semwal" <sumit.semwal@linaro.org>,
	"Christian König" <christian.koenig@amd.com>
Cc: Sukrut Bellary <sukrut.bellary@linux.com>,
	linux-arm-msm@vger.kernel.org, dri-devel@lists.freedesktop.org,
	linaro-mm-sig@lists.linaro.org, linux-media@vger.kernel.org,
	linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org
Subject: [PATCH] accel/qaic: Fix dereferencing freed memory
Date: Fri,  9 Jun 2023 19:12:00 -0700	[thread overview]
Message-ID: <20230610021200.377452-1-sukrut.bellary@linux.com> (raw)

smatch warning:
	drivers/accel/qaic/qaic_data.c:620 qaic_free_object() error:
		dereferencing freed memory 'obj->import_attach'

obj->import_attach is detached and freed using dma_buf_detach().
But used after free to decrease the dmabuf ref count using
dma_buf_put().

Fixes: ff13be830333 ("accel/qaic: Add datapath")
Signed-off-by: Sukrut Bellary <sukrut.bellary@linux.com>
---
 drivers/accel/qaic/qaic_data.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/accel/qaic/qaic_data.c b/drivers/accel/qaic/qaic_data.c
index e42c1f9ffff8..7cba4d680ea8 100644
--- a/drivers/accel/qaic/qaic_data.c
+++ b/drivers/accel/qaic/qaic_data.c
@@ -613,11 +613,13 @@ static int qaic_gem_object_mmap(struct drm_gem_object *obj, struct vm_area_struc
 static void qaic_free_object(struct drm_gem_object *obj)
 {
 	struct qaic_bo *bo = to_qaic_bo(obj);
+	struct dma_buf *dmabuf;
 
 	if (obj->import_attach) {
 		/* DMABUF/PRIME Path */
+		dmabuf = obj->import_attach->dmabuf;
 		dma_buf_detach(obj->import_attach->dmabuf, obj->import_attach);
-		dma_buf_put(obj->import_attach->dmabuf);
+		dma_buf_put(dmabuf);
 	} else {
 		/* Private buffer allocation path */
 		qaic_free_sgt(bo->sgt);
-- 
2.34.1


             reply	other threads:[~2023-06-10  2:12 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-06-10  2:12 Sukrut Bellary [this message]
2023-06-12 11:22 ` [PATCH] accel/qaic: Fix dereferencing freed memory Christian König
2023-06-12 13:03   ` Pranjal Ramajor Asha Kanojiya
2023-06-12 13:21     ` Christian König
2023-06-12 15:09       ` Jeffrey Hugo
2023-06-12 15:47         ` Pranjal Ramajor Asha Kanojiya
2023-06-12 12:44 ` Pranjal Ramajor Asha Kanojiya

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