linux-kernel - [PATCH] misc: fastrpc: Fix dma_buf object leak in fastrpc_map

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Message-ID: <48B368FB4C7007A7+20251017083906.3259343-1-bigfoot@radxa.com>
Date: Fri, 17 Oct 2025 16:39:06 +0800
From: Junhao Xie <bigfoot@...xa.com>
To: Srinivas Kandagatla <srini@...nel.org>,
	Amol Maheshwari <amahesh@....qualcomm.com>
Cc: Arnd Bergmann <arnd@...db.de>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Ling Xu <quic_lxu5@...cinc.com>,
	Dmitry Baryshkov <dmitry.baryshkov@....qualcomm.com>,
	linux-arm-msm@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	stable@...r.kernel.org,
	Junhao Xie <bigfoot@...xa.com>,
	stable@...nel.org,
	Xilin Wu <sophon@...xa.com>
Subject: [PATCH] misc: fastrpc: Fix dma_buf object leak in fastrpc_map_lookup

In fastrpc_map_lookup, dma_buf_get is called to obtain a reference to
the dma_buf for comparison purposes. However, this reference is never
released when the function returns, leading to a dma_buf memory leak.

Fix this by adding dma_buf_put before returning from the function,
ensuring that the temporarily acquired reference is properly released
regardless of whether a matching map is found.

Fixes: 9031626ade38 ("misc: fastrpc: Fix fastrpc_map_lookup operation")
Cc: stable@...nel.org
Signed-off-by: Junhao Xie <bigfoot@...xa.com>
Tested-by: Xilin Wu <sophon@...xa.com>
---
 drivers/misc/fastrpc.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/misc/fastrpc.c b/drivers/misc/fastrpc.c
index 621bce7e101c1..ee652ef01534a 100644
--- a/drivers/misc/fastrpc.c
+++ b/drivers/misc/fastrpc.c
@@ -381,6 +381,8 @@ static int fastrpc_map_lookup(struct fastrpc_user *fl, int fd,
 	}
 	spin_unlock(&fl->lock);
 
+	dma_buf_put(buf);
+
 	return ret;
 }
 
-- 
2.50.1