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From:   Benoit Parrot <bparrot@ti.com>
To:     Hans Verkuil <hverkuil@xs4all.nl>
CC:     Tomi Valkeinen <tomi.valkeinen@ti.com>,
        <linux-media@vger.kernel.org>, <devicetree@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>, Benoit Parrot <bparrot@ti.com>,
        <stable@vger.kernel.org>
Subject: [Patch] media: ti-vpe: cal: fix a kernel oops when unloading module
Date:   Tue, 3 Mar 2020 11:26:29 -0600
Message-ID: <20200303172629.21339-1-bparrot@ti.com>
MIME-Version: 1.0
Content-Type: text/plain
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

After the switch to use v4l2_async_notifier_add_subdev() and
v4l2_async_notifier_cleanup(), unloading the ti_cal module would casue a
kernel oops.

This was root cause to the fact that v4l2_async_notifier_cleanup() tries
to kfree the asd pointer passed into v4l2_async_notifier_add_subdev().

In our case the asd reference was from a statically allocated struct.
So in effect v4l2_async_notifier_cleanup() was trying to free a pointer
that was not kalloc.

So here we switch to using a kzalloc struct instead of a static one.

Fixes: d079f94c9046 ("media: platform: Switch to v4l2_async_notifier_add_subdev")

Cc: stable@vger.kernel.org
Signed-off-by: Benoit Parrot <bparrot@ti.com>
---
 drivers/media/platform/ti-vpe/cal.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/media/platform/ti-vpe/cal.c b/drivers/media/platform/ti-vpe/cal.c
index 6d4cbb8782ed..18fe2cb9dd17 100644
--- a/drivers/media/platform/ti-vpe/cal.c
+++ b/drivers/media/platform/ti-vpe/cal.c
@@ -372,8 +372,6 @@ struct cal_ctx {
 	struct v4l2_subdev	*sensor;
 	struct v4l2_fwnode_endpoint	endpoint;
 
-	struct v4l2_async_subdev asd;
-
 	struct v4l2_fh		fh;
 	struct cal_dev		*dev;
 	struct cc_data		*cc;
@@ -2032,7 +2030,6 @@ static int of_cal_create_instance(struct cal_ctx *ctx, int inst)
 
 	parent = pdev->dev.of_node;
 
-	asd = &ctx->asd;
 	endpoint = &ctx->endpoint;
 
 	ep_node = NULL;
@@ -2040,6 +2037,10 @@ static int of_cal_create_instance(struct cal_ctx *ctx, int inst)
 	sensor_node = NULL;
 	ret = -EINVAL;
 
+	asd = kzalloc(sizeof(*asd), GFP_KERNEL);
+	if (!asd)
+		goto cleanup_exit;
+
 	ctx_dbg(3, ctx, "Scanning Port node for csi2 port: %d\n", inst);
 	for (index = 0; index < CAL_NUM_CSI2_PORTS; index++) {
 		port = of_get_next_port(parent, port);
-- 
2.17.1