[PATCH for v5.3] cec-notifier: clear cec_adap in cec_notifier_unregister
Hans Verkuil
hverkuil-cisco at xs4all.nl
Fri Aug 23 11:12:59 UTC 2019
If cec_notifier_cec_adap_unregister() is called before
cec_unregister_adapter() then everything is OK (and this is the
case today). But if it is the other way around, then
cec_notifier_unregister() is called first, and that doesn't
set n->cec_adap to NULL.
So if e.g. cec_notifier_set_phys_addr() is called after
cec_notifier_unregister() but before cec_unregister_adapter()
then n->cec_adap points to an unregistered and likely deleted
cec adapter. So just set n->cec_adap->notifier and n->cec_adap
to NULL for rubustness.
Eventually cec_notifier_unregister will disappear and this will
be simplified substantially.
Signed-off-by: Hans Verkuil <hverkuil-cisco at xs4all.nl>
---
drivers/media/cec/cec-notifier.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/media/cec/cec-notifier.c b/drivers/media/cec/cec-notifier.c
index 52a867bde15f..4d82a5522072 100644
--- a/drivers/media/cec/cec-notifier.c
+++ b/drivers/media/cec/cec-notifier.c
@@ -218,6 +218,8 @@ void cec_notifier_unregister(struct cec_notifier *n)
mutex_lock(&n->lock);
n->callback = NULL;
+ n->cec_adap->notifier = NULL;
+ n->cec_adap = NULL;
mutex_unlock(&n->lock);
cec_notifier_put(n);
}
--
2.20.1
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