linux-kernel - [PATCH v2 2/5] misc: fastrpc: Don't reference rpmsg

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Date:   Thu, 29 Aug 2019 10:29:23 +0100
From:   Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
To:     gregkh@...uxfoundation.org
Cc:     arnd@...db.de, linux-arm-msm@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        Mayank Chopra <mak.chopra@...eaurora.org>,
        Abhinav Asati <asatiabhi@...eaurora.org>,
        Vamsi Singamsetty <vamssi@...eaurora.org>,
        Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
Subject: [PATCH v2 2/5] misc: fastrpc: Don't reference rpmsg_device after remove

From: Bjorn Andersson <bjorn.andersson@...aro.org>

As fastrpc_rpmsg_remove() returns the rpdev of the channel context is no
longer a valid object, so ensure to update the channel context to no
longer reference the old object and guard in the invoke code path
against dereferencing it.

Signed-off-by: Bjorn Andersson <bjorn.andersson@...aro.org>
Signed-off-by: Mayank Chopra <mak.chopra@...eaurora.org>
Signed-off-by: Abhinav Asati <asatiabhi@...eaurora.org>
Signed-off-by: Vamsi Singamsetty <vamssi@...eaurora.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
---
 drivers/misc/fastrpc.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/misc/fastrpc.c b/drivers/misc/fastrpc.c
index c019e867e7fa..59ee6de26229 100644
--- a/drivers/misc/fastrpc.c
+++ b/drivers/misc/fastrpc.c
@@ -913,6 +913,9 @@ static int fastrpc_internal_invoke(struct fastrpc_user *fl,  u32 kernel,
 	if (!fl->sctx)
 		return -EINVAL;
 
+	if (!fl->cctx->rpdev)
+		return -EPIPE;
+
 	ctx = fastrpc_context_alloc(fl, kernel, sc, args);
 	if (IS_ERR(ctx))
 		return PTR_ERR(ctx);
@@ -1495,6 +1498,7 @@ static void fastrpc_rpmsg_remove(struct rpmsg_device *rpdev)
 	misc_deregister(&cctx->miscdev);
 	of_platform_depopulate(&rpdev->dev);
 
+	cctx->rpdev = NULL;
 	fastrpc_channel_ctx_put(cctx);
 }
 
-- 
2.21.0