| Message ID | 20210323203946.2159693-7-samitolvanen@google.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | Add support for Clang CFI | expand |
On Tue, Mar 23, 2021 at 01:39:35PM -0700, Sami Tolvanen wrote: > 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 != ktead_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@google.com> Reviewed-by: Kees Cook <keescook@chromium.org>
diff --git a/kernel/kthread.c b/kernel/kthread.c index 1578973c5740..a1972eba2917 100644 --- a/kernel/kthread.c +++ b/kernel/kthread.c @@ -963,7 +963,8 @@ 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); + WARN_ON_FUNCTION_MISMATCH(timer->function, + kthread_delayed_work_timer_fn); /* * If @delay is 0, queue @dwork->work immediately. This is for
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 != ktead_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@google.com> --- kernel/kthread.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)