[PATCH 6.1.y] media: microchip-csi2dc: fix async notifier leak on probe error path

[Sasha Levin <sashal@kernel.org>]

From: Cong Nguyen <congnt264@gmail.com>

[ Upstream commit c7528789244ce7329ca883170fb9315d739ae985 ]

csi2dc_of_parse() ends up calling csi2dc_prepare_notifier(), which
registers the V4L2 async notifier with v4l2_async_nf_register(). The
probe error label csi2dc_probe_cleanup_notifier is reached after
csi2dc_of_parse() has already succeeded (e.g. when media entity init,
csi2dc_power() or v4l2_async_register_subdev() fail), but it calls only
v4l2_async_nf_cleanup() and never v4l2_async_nf_unregister().

The notifier therefore stays chained in the global notifier_list while
the enclosing struct csi2dc_device is freed, leading to list corruption
and a use-after-free when the list is next walked.

Unregister the notifier before cleaning it up on the error path,
matching the teardown already done in csi2dc_remove().

Fixes: 2de0b3c0f678 ("media: atmel: introduce microchip csi2dc driver")
Cc: stable@vger.kernel.org
Assisted-by: Claude:claude-opus-4
Signed-off-by: Cong Nguyen <congnt264@gmail.com>
Reviewed-by: Eugen Hristev <ehristev@kernel.org>
Signed-off-by: Hans Verkuil <hverkuil+cisco@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/media/platform/atmel/microchip-csi2dc.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/media/platform/atmel/microchip-csi2dc.c b/drivers/media/platform/atmel/microchip-csi2dc.c
index d5b359f607ae9..19d6cc5984445 100644
--- a/drivers/media/platform/atmel/microchip-csi2dc.c
+++ b/drivers/media/platform/atmel/microchip-csi2dc.c
@@ -734,6 +734,7 @@ static int csi2dc_probe(struct platform_device *pdev)
 	return 0;
 
 csi2dc_probe_cleanup_notifier:
+	v4l2_async_nf_unregister(&csi2dc->notifier);
 	v4l2_async_nf_cleanup(&csi2dc->notifier);
 csi2dc_probe_cleanup_entity:
 	media_entity_cleanup(&csi2dc->csi2dc_sd.entity);
-- 
2.53.0