From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760199AbcIWOvT (ORCPT ); Fri, 23 Sep 2016 10:51:19 -0400 Received: from mail-wm0-f46.google.com ([74.125.82.46]:35806 "EHLO mail-wm0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751716AbcIWOvR (ORCPT ); Fri, 23 Sep 2016 10:51:17 -0400 From: Andrey Konovalov To: Andrew Morton , Dmitry Vyukov , Nicolai Stange , Andrey Ryabinin , Kees Cook , James Morse , linux-kernel@vger.kernel.org, vegard.nossum@oracle.com, quentin.casasnovas@oracle.com, ryabinin.a.a@gmail.com Cc: Andrey Konovalov Subject: [PATCH] kcov: properly check if we are in an interrupt Date: Fri, 23 Sep 2016 16:51:13 +0200 Message-Id: <1474642273-112248-1-git-send-email-andreyknvl@google.com> X-Mailer: git-send-email 2.8.0.rc3.226.g39d4020 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org in_interrupt() returns a nonzero value when we are either in an interrupt or have bh disabled via local_bh_disable(). Since we are interested in only ignoring coverage from actual interrupts, do a proper check of whether we are really in an interrupt. Signed-off-by: Andrey Konovalov --- It would look totally better to reuse in_irq(), in_serving_softirq() and in_nmi() instead of checking flags manually, but that leads to slower generated code (three separate tests for each of the flags). Would it be better to add another macro to preempt.h that would check if we're actually in interrupt and use it? kernel/kcov.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/kernel/kcov.c b/kernel/kcov.c index 8d44b3f..47c35a8 100644 --- a/kernel/kcov.c +++ b/kernel/kcov.c @@ -54,7 +54,8 @@ void notrace __sanitizer_cov_trace_pc(void) * We are interested in code coverage as a function of a syscall inputs, * so we ignore code executed in interrupts. */ - if (!t || in_interrupt()) + if (!t || (preempt_count() & (HARDIRQ_MASK | SOFTIRQ_OFFSET + | NMI_MASK))) return; mode = READ_ONCE(t->kcov_mode); if (mode == KCOV_MODE_TRACE) { -- 2.8.0.rc3.226.g39d4020