Re: [PATCH v2 05/17] workqueue: use WARN_ON_FUNCTION_MISMATCH
From: Nick Desaulniers <ndesaulniers@google.com>
Date: 2021-03-18 18:51:24
Also in:
bpf, linux-arch, linux-hardening, linux-kbuild, linux-pci, lkml
On Thu, Mar 18, 2021 at 10:11 AM Sami Tolvanen [off-list ref] wrote:
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.
Does __cficanonical help with such comparisons? Or would that be a very invasive change, if the concern was to try to keep these checks in place for CONFIG_CFI_CLANG?
quoted hunk ↗ jump to hunk
Signed-off-by: Sami Tolvanen <samitolvanen@google.com> --- 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
-- Thanks, ~Nick Desaulniers _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel