* [PATCH] cec: safely unhook lists in cec_data
@ 2021-11-24 10:38 Hans Verkuil
0 siblings, 0 replies; only message in thread
From: Hans Verkuil @ 2021-11-24 10:38 UTC (permalink / raw)
To: Linux Media Mailing List
smatch warns about data->list not being removed from list:
drivers/media/cec/core/cec-adap.c:926 cec_transmit_msg_fh() warn: '&data->list' not removed from list
It is a false warning, but it doesn't hurt to make the code more robust
and safely unhook data->list and data->xfer_list together with a WARN_ON
if this is actually ever needed (this really shouldn't happen).
Note that fixing the data->list warning just replaced it with a new similar warning
for data->xfer_list, so both needed to be addressed.
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
---
drivers/media/cec/core/cec-adap.c | 8 +++++++-
drivers/media/cec/core/cec-api.c | 2 +-
2 files changed, 8 insertions(+), 2 deletions(-)
diff --git a/drivers/media/cec/core/cec-adap.c b/drivers/media/cec/core/cec-adap.c
index 79fa36de8a04..3eea1d6a9308 100644
--- a/drivers/media/cec/core/cec-adap.c
+++ b/drivers/media/cec/core/cec-adap.c
@@ -342,7 +342,7 @@ static void cec_data_completed(struct cec_data *data)
* Without that we would be referring to a closed filehandle.
*/
if (data->fh)
- list_del(&data->xfer_list);
+ list_del_init(&data->xfer_list);
if (data->blocking) {
/*
@@ -898,6 +898,8 @@ int cec_transmit_msg_fh(struct cec_adapter *adap, struct cec_msg *msg,
if (fh)
list_add_tail(&data->xfer_list, &fh->xfer_list);
+ else
+ INIT_LIST_HEAD(&data->xfer_list);
list_add_tail(&data->list, &adap->transmit_queue);
adap->transmit_queue_sz++;
@@ -923,6 +925,10 @@ int cec_transmit_msg_fh(struct cec_adapter *adap, struct cec_msg *msg,
/* The transmit completed (possibly with an error) */
*msg = data->msg;
+ if (WARN_ON(!list_empty(&data->list)))
+ list_del(&data->list);
+ if (WARN_ON(!list_empty(&data->xfer_list)))
+ list_del(&data->xfer_list);
kfree(data);
return 0;
}
diff --git a/drivers/media/cec/core/cec-api.c b/drivers/media/cec/core/cec-api.c
index 769e6b4cddce..0edb7142afdb 100644
--- a/drivers/media/cec/core/cec-api.c
+++ b/drivers/media/cec/core/cec-api.c
@@ -669,7 +669,7 @@ static int cec_release(struct inode *inode, struct file *filp)
data->blocking = false;
data->fh = NULL;
- list_del(&data->xfer_list);
+ list_del_init(&data->xfer_list);
}
mutex_unlock(&adap->lock);
while (!list_empty(&fh->msgs)) {
--
2.33.0
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2021-11-24 10:38 [PATCH] cec: safely unhook lists in cec_data Hans Verkuil
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