[for,v6.10,2/4] media: cec: cec-api: add locking in cec_release()

Commit Message

Hans Verkuil May 2, 2024, 11:38 a.m. UTC

When cec_release() uses fh->msgs it has to take fh->lock,
otherwise the list can get corrupted.

Signed-off-by: Hans Verkuil <[e-mail]>
Reported-by: Yang, Chenyuan <[e-mail]>
Fixes: ca684386e6e2 ("[media] cec: add HDMI CEC framework (api)")
Closes: https://lore.kernel.org/linux-media/[e-mail]/
---
 drivers/media/cec/core/cec-api.c | 3 +++
 1 file changed, 3 insertions(+)

Patch

diff --git a/drivers/media/cec/core/cec-api.c b/drivers/media/cec/core/cec-api.c
index 67dc79ef17050..d64bb716f9c68 100644
--- a/drivers/media/cec/core/cec-api.c
+++ b/drivers/media/cec/core/cec-api.c
@@ -664,6 +664,8 @@  static int cec_release(struct inode *inode, struct file *filp)
 		list_del_init(&data->xfer_list);
 	}
 	mutex_unlock(&adap->lock);
+
+	mutex_lock(&fh->lock);
 	while (!list_empty(&fh->msgs)) {
 		struct cec_msg_entry *entry =
 			list_first_entry(&fh->msgs, struct cec_msg_entry, list);
@@ -681,6 +683,7 @@  static int cec_release(struct inode *inode, struct file *filp)
 			kfree(entry);
 		}
 	}
+	mutex_unlock(&fh->lock);
 	kfree(fh);
 
 	cec_put_device(devnode);