From: Dan Carpenter <dan.carpen...@oracle.com>

[ Upstream commit ce814ad4bb52bfc7c0472e6da0aa742ab88f4361 ]

The "channel" is added to the "dev->channels" but then if
v4l2_m2m_ctx_init() fails then we free "channel" but it's still on the
list so it could lead to a use after free.  Let's not add it to the
list until after v4l2_m2m_ctx_init() succeeds.

Fixes: cc62c74749a3 ("media: allegro: add missed checks in allegro_open()")
Signed-off-by: Dan Carpenter <dan.carpen...@oracle.com>
Reviewed-by: Michael Tretter <m.tret...@pengutronix.de>
Signed-off-by: Hans Verkuil <hverkuil-ci...@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+hua...@kernel.org>
Signed-off-by: Sasha Levin <sas...@kernel.org>
---
 drivers/staging/media/allegro-dvt/allegro-core.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/staging/media/allegro-dvt/allegro-core.c 
b/drivers/staging/media/allegro-dvt/allegro-core.c
index 9f718f43282bc..640451134072b 100644
--- a/drivers/staging/media/allegro-dvt/allegro-core.c
+++ b/drivers/staging/media/allegro-dvt/allegro-core.c
@@ -2483,8 +2483,6 @@ static int allegro_open(struct file *file)
        INIT_LIST_HEAD(&channel->buffers_reference);
        INIT_LIST_HEAD(&channel->buffers_intermediate);
 
-       list_add(&channel->list, &dev->channels);
-
        channel->fh.m2m_ctx = v4l2_m2m_ctx_init(dev->m2m_dev, channel,
                                                allegro_queue_init);
 
@@ -2493,6 +2491,7 @@ static int allegro_open(struct file *file)
                goto error;
        }
 
+       list_add(&channel->list, &dev->channels);
        file->private_data = &channel->fh;
        v4l2_fh_add(&channel->fh);
 
-- 
2.27.0



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