[PATCH v2 05/17] workqueue: use WARN_ON_FUNCTION_MISMATCH

From: Sami Tolvanen
Date: Thu Mar 18 2021 - 13:12:13 EST


With CONFIG_CFI_CLANG, a callback function passed to
__queue_delayed_work from a module points to a jump table entry
defined in the module instead of the one used in the core kernel,
which breaks function address equality in this check:

WARN_ON_ONCE(timer->function != delayed_work_timer_fn);

Use WARN_ON_FUNCTION_MISMATCH() instead to disable the warning
when CFI and modules are both enabled.

Signed-off-by: Sami Tolvanen <samitolvanen@xxxxxxxxxx>
---
kernel/workqueue.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 0d150da252e8..03fe07d2f39f 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -1630,7 +1630,7 @@ static void __queue_delayed_work(int cpu, struct workqueue_struct *wq,
struct work_struct *work = &dwork->work;

WARN_ON_ONCE(!wq);
- WARN_ON_ONCE(timer->function != delayed_work_timer_fn);
+ WARN_ON_FUNCTION_MISMATCH(timer->function, delayed_work_timer_fn);
WARN_ON_ONCE(timer_pending(timer));
WARN_ON_ONCE(!list_empty(&work->entry));

--
2.31.0.291.g576ba9dcdaf-goog