linux-kernel - [PATCH] dma-buf: fix reference count leak in dma_buf_poll_add

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Message-ID: <aNKBIcpF6kZRG6Mg@stanley.mountain>
Date: Tue, 23 Sep 2025 14:14:41 +0300
From: Dan Carpenter <dan.carpenter@...aro.org>
To: Christian König <christian.koenig@....com>
Cc: Sumit Semwal <sumit.semwal@...aro.org>,
	Simona Vetter <simona.vetter@...ll.ch>, linux-media@...r.kernel.org,
	dri-devel@...ts.freedesktop.org, linaro-mm-sig@...ts.linaro.org,
	linux-kernel@...r.kernel.org, kernel-janitors@...r.kernel.org
Subject: [PATCH] dma-buf: fix reference count leak in dma_buf_poll_add_cb()

Call dma_fence_put(fence) if dma_fence_add_callback() fails.

Fixes: 6b51b02a3a0a ("dma-buf: fix and rework dma_buf_poll v7")
Signed-off-by: Dan Carpenter <dan.carpenter@...aro.org>
---
>From code review, not from testing.  Please review carefully.

 drivers/dma-buf/dma-buf.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c
index 2bcf9ceca997..a14e1f50b090 100644
--- a/drivers/dma-buf/dma-buf.c
+++ b/drivers/dma-buf/dma-buf.c
@@ -301,9 +301,9 @@ static bool dma_buf_poll_add_cb(struct dma_resv *resv, bool write,
 				fence) {
 		dma_fence_get(fence);
 		r = dma_fence_add_callback(fence, &dcb->cb, dma_buf_poll_cb);
+		dma_fence_put(fence);
 		if (!r)
 			return true;
-		dma_fence_put(fence);
 	}
 
 	return false;
-- 
2.51.0