linux-kernel - [PATCH v3 02/11] media: cadence: csi2rx: Unregister v4l2 async notifier

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Message-ID: <20210624192200.22559-3-p.yadav@ti.com>
Date:   Fri, 25 Jun 2021 00:51:51 +0530
From:   Pratyush Yadav <p.yadav@...com>
To:     Mauro Carvalho Chehab <mchehab@...nel.org>
CC:     Laurent Pinchart <laurent.pinchart@...asonboard.com>,
        Vignesh Raghavendra <vigneshr@...com>,
        Tomi Valkeinen <tomi.valkeinen@...asonboard.com>,
        Nikhil Devshatwar <nikhil.nd@...com>,
        Pratyush Yadav <p.yadav@...com>,
        Benoit Parrot <bparrot@...com>,
        Maxime Ripard <mripard@...nel.org>,
        Niklas Söderlund 
        <niklas.soderlund+renesas@...natech.se>,
        Sakari Ailus <sakari.ailus@...ux.intel.com>,
        <linux-kernel@...r.kernel.org>, <linux-media@...r.kernel.org>
Subject: [PATCH v3 02/11] media: cadence: csi2rx: Unregister v4l2 async notifier

The notifier is added to the global notifier list when registered. When
the module is removed, the struct csi2rx_priv in which the notifier is
embedded, is destroyed. As a result the notifier list has a reference to
a notifier that no longer exists. This causes invalid memory accesses
when the list is iterated over. Similar for when the probe fails.

Unregister and clean up the notifier to avoid this.

Fixes: 1fc3b37f34f6 ("media: v4l: cadence: Add Cadence MIPI-CSI2 RX driver")
Signed-off-by: Pratyush Yadav <p.yadav@...com>

---

Changes in v3:
- New in v3.

 drivers/media/platform/cadence/cdns-csi2rx.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/media/platform/cadence/cdns-csi2rx.c b/drivers/media/platform/cadence/cdns-csi2rx.c
index f2b4ddd31177..bf2e024d73c5 100644
--- a/drivers/media/platform/cadence/cdns-csi2rx.c
+++ b/drivers/media/platform/cadence/cdns-csi2rx.c
@@ -471,6 +471,7 @@ static int csi2rx_probe(struct platform_device *pdev)
 	return 0;
 
 err_cleanup:
+	v4l2_async_notifier_unregister(&csi2rx->notifier);
 	v4l2_async_notifier_cleanup(&csi2rx->notifier);
 err_free_priv:
 	kfree(csi2rx);
@@ -481,6 +482,8 @@ static int csi2rx_remove(struct platform_device *pdev)
 {
 	struct csi2rx_priv *csi2rx = platform_get_drvdata(pdev);
 
+	v4l2_async_notifier_unregister(&csi2rx->notifier);
+	v4l2_async_notifier_cleanup(&csi2rx->notifier);
 	v4l2_async_unregister_subdev(&csi2rx->subdev);
 	kfree(csi2rx);
 
-- 
2.30.0