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Subject[PATCH] media, cx231xx: Fix double free on close
In cx231xx_v4l2_close() there are two calls to
cx231xx_release_resources(dev) followed by kfree(dev). That is a
problem since cx231xx_release_resources() already kfree()'s its
argument, so we end up doing a double free.

Easily resolved by just removing the redundant kfree() calls after the
calls to cx231xx_release_resources().

I also changed the 'dev = NULL' assignments (which are rather
pointless since 'dev' is about to go out of scope), to 'fh->dev = NULL'
since it looks to me that that is what was actually intended.
And I removed the 'dev = NULL' assignment at the end of
cx231xx_release_resources() since it is pointless.

Signed-off-by: Jesper Juhl <jj@chaosbits.net>
---
drivers/media/video/cx231xx/cx231xx-cards.c | 1 -
drivers/media/video/cx231xx/cx231xx-video.c | 6 ++----
2 files changed, 2 insertions(+), 5 deletions(-)

Please note that I do not have hardware to actually test this properly,
so this patch is compile tested only.
I also do not have very intimate knowledge of this driver, so please
review carefully before applying.

diff --git a/drivers/media/video/cx231xx/cx231xx-cards.c b/drivers/media/video/cx231xx/cx231xx-cards.c
index 875a7ce..8ed460d 100644
--- a/drivers/media/video/cx231xx/cx231xx-cards.c
+++ b/drivers/media/video/cx231xx/cx231xx-cards.c
@@ -861,7 +861,6 @@ void cx231xx_release_resources(struct cx231xx *dev)
kfree(dev->sliced_cc_mode.alt_max_pkt_size);
kfree(dev->ts1_mode.alt_max_pkt_size);
kfree(dev);
- dev = NULL;
}

/*
diff --git a/drivers/media/video/cx231xx/cx231xx-video.c b/drivers/media/video/cx231xx/cx231xx-video.c
index 829a41b..7f916f0 100644
--- a/drivers/media/video/cx231xx/cx231xx-video.c
+++ b/drivers/media/video/cx231xx/cx231xx-video.c
@@ -2319,8 +2319,7 @@ static int cx231xx_v4l2_close(struct file *filp)
if (dev->state & DEV_DISCONNECTED) {
if (atomic_read(&dev->devlist_count) > 0) {
cx231xx_release_resources(dev);
- kfree(dev);
- dev = NULL;
+ fh->dev = NULL;
return 0;
}
return 0;
@@ -2350,8 +2349,7 @@ static int cx231xx_v4l2_close(struct file *filp)
free the remaining resources */
if (dev->state & DEV_DISCONNECTED) {
cx231xx_release_resources(dev);
- kfree(dev);
- dev = NULL;
+ fh->dev = NULL;
return 0;
}

--
1.7.9.2

--
Jesper Juhl <jj@chaosbits.net> http://www.chaosbits.net/
Don't top-post http://www.catb.org/jargon/html/T/top-post.html
Plain text mails only, please.



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