With CONFIG_CFI_CLANG, a callback function passed to __kthread_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 != kthread_delayed_work_timer_fn); Disable the warning when CFI and modules are enabled. Signed-off-by: Sami Tolvanen <samitolvanen@xxxxxxxxxx> --- kernel/kthread.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/kernel/kthread.c b/kernel/kthread.c index 1578973c5740..af5fee350586 100644 --- a/kernel/kthread.c +++ b/kernel/kthread.c @@ -963,7 +963,13 @@ static void __kthread_queue_delayed_work(struct kthread_worker *worker, struct timer_list *timer = &dwork->timer; struct kthread_work *work = &dwork->work; - WARN_ON_ONCE(timer->function != kthread_delayed_work_timer_fn); + /* + * With CFI, timer->function can point to a jump table entry in a module, + * which fails the comparison. Disable the warning if CFI and modules are + * both enabled. + */ + if (!IS_ENABLED(CONFIG_CFI_CLANG) || !IS_ENABLED(CONFIG_MODULES)) + WARN_ON_ONCE(timer->function != kthread_delayed_work_timer_fn); /* * If @delay is 0, queue @dwork->work immediately. This is for -- 2.31.0.rc2.261.g7f71774620-goog
