Patch "[media] media: am437x-vpfe: Fix a race condition during release" has been added to the 4.2-stable tree

Patch "[media] media: am437x-vpfe: Fix a race condition during release" has been added to the 4.2-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    [media] media: am437x-vpfe: Fix a race condition during release

to the 4.2-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     media-am437x-vpfe-fix-a-race-condition-during-release.patch
and it can be found in the queue-4.2 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From c99235fa3ef833c3c23926085f2bb68851c8460a Mon Sep 17 00:00:00 2001
From: Benoit Parrot <bparrot@ti.com>
Date: Wed, 15 Jul 2015 18:00:06 -0300
Subject: [media] media: am437x-vpfe: Fix a race condition during release

From: Benoit Parrot <bparrot@ti.com>

commit c99235fa3ef833c3c23926085f2bb68851c8460a upstream.

There was a race condition where during cleanup/release operation
on-going streaming would cause a kernel panic because the hardware
module was disabled prematurely with IRQ still pending.

Fixes: 417d2e507edc ("[media] media: platform: add VPFE capture driver support for AM437X")

Signed-off-by: Benoit Parrot <bparrot@ti.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/media/platform/am437x/am437x-vpfe.c |   14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

--- a/drivers/media/platform/am437x/am437x-vpfe.c
+++ b/drivers/media/platform/am437x/am437x-vpfe.c
@@ -1186,14 +1186,24 @@ static int vpfe_initialize_device(struct
 static int vpfe_release(struct file *file)
 {
 	struct vpfe_device *vpfe = video_drvdata(file);
+	bool fh_singular;
 	int ret;
 
 	mutex_lock(&vpfe->lock);
 
-	if (v4l2_fh_is_singular_file(file))
-		vpfe_ccdc_close(&vpfe->ccdc, vpfe->pdev);
+	/* Save the singular status before we call the clean-up helper */
+	fh_singular = v4l2_fh_is_singular_file(file);
+
+	/* the release helper will cleanup any on-going streaming */
 	ret = _vb2_fop_release(file, NULL);
 
+	/*
+	 * If this was the last open file.
+	 * Then de-initialize hw module.
+	 */
+	if (fh_singular)
+		vpfe_ccdc_close(&vpfe->ccdc, vpfe->pdev);
+
 	mutex_unlock(&vpfe->lock);
 
 	return ret;


Patches currently in stable-queue which might be from bparrot@ti.com are

queue-4.2/media-am437x-vpfe-fix-a-race-condition-during-release.patch
queue-4.2/media-am437x-vpfe-requested-frame-size-and-fmt-overwritten-by-current-sensor-setting.patch