From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C6A33CA9EAF for ; Fri, 25 Oct 2019 03:39:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A4D9621929 for ; Fri, 25 Oct 2019 03:39:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388090AbfJYDif (ORCPT ); Thu, 24 Oct 2019 23:38:35 -0400 Received: from mx2.suse.de ([195.135.220.15]:43458 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727145AbfJYDif (ORCPT ); Thu, 24 Oct 2019 23:38:35 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id E8373B25C; Fri, 25 Oct 2019 03:38:33 +0000 (UTC) From: Davidlohr Bueso To: mingo@kernel.org Cc: peterz@infradead.org, dave@stgolabs.net, linux-kernel@vger.kernel.org, Davidlohr Bueso Subject: [PATCH -tip] locking/mutex: Complain upon api misuse wrt interrupt context Date: Thu, 24 Oct 2019 20:36:34 -0700 Message-Id: <20191025033634.3330-1-dave@stgolabs.net> X-Mailer: git-send-email 2.16.4 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Sprinkle warning checks, under CONFIG_DEBUG_MUTEXES. While the mutex rules and semantics are explicitly documented, this allows to expose any abusers and robustifies the whole thing. While trylock and unlock are non-blocking, calling from irq context is still forbidden (lock must be within the same context as unlock). Signed-off-by: Davidlohr Bueso --- kernel/locking/mutex.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/kernel/locking/mutex.c b/kernel/locking/mutex.c index 468a9b8422e3..7e9c316c646c 100644 --- a/kernel/locking/mutex.c +++ b/kernel/locking/mutex.c @@ -733,6 +733,9 @@ static noinline void __sched __mutex_unlock_slowpath(struct mutex *lock, unsigne */ void __sched mutex_unlock(struct mutex *lock) { +#ifdef CONFIG_DEBUG_MUTEXES + WARN_ON(in_interrupt()); +#endif #ifndef CONFIG_DEBUG_LOCK_ALLOC if (__mutex_unlock_fast(lock)) return; @@ -1413,6 +1416,7 @@ int __sched mutex_trylock(struct mutex *lock) #ifdef CONFIG_DEBUG_MUTEXES DEBUG_LOCKS_WARN_ON(lock->magic != lock); + WARN_ON(in_interrupt()); #endif locked = __mutex_trylock(lock); -- 2.16.4