[PATCH 5.15 015/164] PM: wakeup: Handle empty list in wakeup_sources_walk_start()

Sasha Levin
2026-02-28T18:15:18Z

From: Samuel Wu <wusamuel@google.com>

[ Upstream commit 75ce02f4bc9a8b8350b6b1b01872467b0cc960cc ]

In the case of an empty wakeup_sources list, wakeup_sources_walk_start()
will return an invalid but non-NULL address. This also affects wrappers
of the aforementioned function, like for_each_wakeup_source().

Update wakeup_sources_walk_start() to return NULL in case of an empty
list.

Fixes: b4941adb24c0 ("PM: wakeup: Add routine to help fetch wakeup source object.")
Signed-off-by: Samuel Wu <wusamuel@google.com>
[ rjw: Subject and changelog edits ]
Link: https://patch.msgid.link/20260124012133.2451708-2-wusamuel@google.com
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/base/power/wakeup.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/base/power/wakeup.c b/drivers/base/power/wakeup.c
index 8666590201c9a..4ef4c8dfd2bc7 100644
--- a/drivers/base/power/wakeup.c
+++ b/drivers/base/power/wakeup.c
@@ -285,9 +285,7 @@ EXPORT_SYMBOL_GPL(wakeup_sources_read_unlock);
*/
struct wakeup_source *wakeup_sources_walk_start(void)
{
- struct list_head *ws_head = &wakeup_sources;
-
- return list_entry_rcu(ws_head->next, struct wakeup_source, entry);
+ return list_first_or_null_rcu(&wakeup_sources, struct wakeup_source, entry);
}
EXPORT_SYMBOL_GPL(wakeup_sources_walk_start);

--
2.51.0