Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756506AbdCUJKo (ORCPT ); Tue, 21 Mar 2017 05:10:44 -0400 Received: from mail-wr0-f181.google.com ([209.85.128.181]:34530 "EHLO mail-wr0-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751176AbdCUJKm (ORCPT ); Tue, 21 Mar 2017 05:10:42 -0400 From: Dmitry Vyukov To: akpm@linux-foundation.org, linux-mm@kvack.org Cc: Dmitry Vyukov , Kefeng Wang , James Morse , Alexander Popov , Andrey Konovalov , linux-kernel@vger.kernel.org, syzkaller@googlegroups.com Subject: [PATCH] kcov: simplify interrupt check Date: Tue, 21 Mar 2017 10:10:26 +0100 Message-Id: <20170321091026.139655-1-dvyukov@google.com> X-Mailer: git-send-email 2.12.1.500.gab5fba24ee-goog Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1623 Lines: 43 in_interrupt() semantics are confusing and wrong for most users as it also returns true when bh is disabled. Thus we open coded a proper check for interrupts in __sanitizer_cov_trace_pc() with a lengthy explanatory comment. Use the new in_task() predicate instead. Signed-off-by: Dmitry Vyukov Cc: Andrew Morton Cc: Kefeng Wang Cc: James Morse Cc: Alexander Popov Cc: Andrey Konovalov Cc: linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org Cc: syzkaller@googlegroups.com --- kernel/kcov.c | 9 +-------- 1 file changed, 1 insertion(+), 8 deletions(-) diff --git a/kernel/kcov.c b/kernel/kcov.c index 85e5546cd791..cd771993f96f 100644 --- a/kernel/kcov.c +++ b/kernel/kcov.c @@ -60,15 +60,8 @@ 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. - * The checks for whether we are in an interrupt are open-coded, because - * 1. We can't use in_interrupt() here, since it also returns true - * when we are inside local_bh_disable() section. - * 2. We don't want to use (in_irq() | in_serving_softirq() | in_nmi()), - * since that leads to slower generated code (three separate tests, - * one for each of the flags). */ - if (!t || (preempt_count() & (HARDIRQ_MASK | SOFTIRQ_OFFSET - | NMI_MASK))) + if (!t || !in_task()) return; mode = READ_ONCE(t->kcov_mode); if (mode == KCOV_MODE_TRACE) { -- 2.12.1.500.gab5fba24ee-goog