linux-kernel - [PATCH v4 3/6] tee: fix put order in teedev_close

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Message-Id: <20210818101849.602257-4-jens.wiklander@linaro.org>
Date:   Wed, 18 Aug 2021 12:18:46 +0200
From:   Jens Wiklander <jens.wiklander@...aro.org>
To:     linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        op-tee@...ts.trustedfirmware.org, devicetree@...r.kernel.org,
        linux-doc@...r.kernel.org
Cc:     Jerome Forissier <jerome@...issier.org>,
        Etienne Carriere <etienne.carriere@...aro.org>,
        Sumit Garg <sumit.garg@...aro.org>,
        Vincent Guittot <vincent.guittot@...aro.org>,
        Rob Herring <robh+dt@...nel.org>,
        Jonathan Corbet <corbet@....net>,
        Ard Biesheuvel <ardb@...nel.org>,
        Marc Zyngier <maz@...nel.org>,
        Jens Wiklander <jens.wiklander@...aro.org>
Subject: [PATCH v4 3/6] tee: fix put order in teedev_close_context()

Prior to this patch was teedev_close_context() calling tee_device_put()
before teedev_ctx_put() leading to teedev_ctx_release() accessing
ctx->teedev just after the reference counter was decreased on the
teedev. Fix this by calling teedev_ctx_put() before tee_device_put().

Fixes: 217e0250cccb ("tee: use reference counting for tee_context")
Signed-off-by: Jens Wiklander <jens.wiklander@...aro.org>
---
 drivers/tee/tee_core.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/tee/tee_core.c b/drivers/tee/tee_core.c
index 2b37bc408fc3..85102d12d716 100644
--- a/drivers/tee/tee_core.c
+++ b/drivers/tee/tee_core.c
@@ -98,8 +98,10 @@ void teedev_ctx_put(struct tee_context *ctx)
 
 static void teedev_close_context(struct tee_context *ctx)
 {
-	tee_device_put(ctx->teedev);
+	struct tee_device *teedev = ctx->teedev;
+
 	teedev_ctx_put(ctx);
+	tee_device_put(teedev);
 }
 
 static int tee_open(struct inode *inode, struct file *filp)
-- 
2.31.1