On 27-03-22, 13:39, Xiaomeng Tong wrote:
The bug is here: dev = new_dev->dev;
The list iterator 'new_dev' will point to a bogus position containing HEAD if the list is empty or no element is found. This case must be checked before any use of the iterator, otherwise it will lead to a invalid memory access.
To fix this bug, add an check. Use a new variable 'iter' as the list iterator, while use the old variable 'new_dev' as a dedicated pointer to point to the found element.
Cc: stable@vger.kernel.org Fixes: deaa51465105a ("PM / OPP: Add debugfs support") Signed-off-by: Xiaomeng Tong xiam0nd.tong@gmail.com
drivers/opp/debugfs.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-)
diff --git a/drivers/opp/debugfs.c b/drivers/opp/debugfs.c index 596c185b5dda..a4476985e4ce 100644 --- a/drivers/opp/debugfs.c +++ b/drivers/opp/debugfs.c @@ -187,14 +187,19 @@ void opp_debug_register(struct opp_device *opp_dev, struct opp_table *opp_table) static void opp_migrate_dentry(struct opp_device *opp_dev, struct opp_table *opp_table) {
- struct opp_device *new_dev;
- struct opp_device *new_dev = NULL, *iter; const struct device *dev; struct dentry *dentry;
/* Look for next opp-dev */
- list_for_each_entry(new_dev, &opp_table->dev_list, node)
if (new_dev != opp_dev)
- list_for_each_entry(iter, &opp_table->dev_list, node)
if (iter != opp_dev) {new_dev = iter; break;}- if (!new_dev)
return;
I think you missed this check in the parent function ?
if (!list_is_singular(&opp_table->dev_list)) {
i.e. this bug can never happen.