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=-10.3 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,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 4A143C47255 for ; Mon, 11 May 2020 20:42:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 28F5220752 for ; Mon, 11 May 2020 20:42:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1589229769; bh=lWxUFO7+ilIRrLEBP9LvhbxGDPBqUhNNYn0A1J7W2VE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=q5zJmjL/vKRFzq0vd2h/Lo3GmYPRZRs8Xso7uKinm+qH1aYFoVJGVRnBFgyuhe9QS vEql7+RJes0F6ic6qqH8pUZyM//L5Bd4oGXoRGX8gOJ18dnWIRlCU4DyjfsTtCs5ty EoyVlt1VDE68W9e42UxlOYMKA+E3Fp0H7sCrpIZs= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731849AbgEKUms (ORCPT ); Mon, 11 May 2020 16:42:48 -0400 Received: from mail.kernel.org ([198.145.29.99]:54356 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731840AbgEKUmq (ORCPT ); Mon, 11 May 2020 16:42:46 -0400 Received: from localhost.localdomain (236.31.169.217.in-addr.arpa [217.169.31.236]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 8146420836; Mon, 11 May 2020 20:42:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1589229765; bh=lWxUFO7+ilIRrLEBP9LvhbxGDPBqUhNNYn0A1J7W2VE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=qjb7EWAhwsAK8r8X5IjdzaHM9FobA0j7igLn49bXpyLiLUxI1dUs85V3/UXVo3vKf WgBHifBBfmia/O6jxQNJlTNdsPyfOSUVnVOqzg4UqsZvUlKBVFwwI9gXLhZAqOGgff k26aC9FA/ZJayc6oEp+KJ08Va11/2ss8HQsmdYas= From: Will Deacon To: linux-kernel@vger.kernel.org Cc: elver@google.com, tglx@linutronix.de, paulmck@kernel.org, mingo@kernel.org, peterz@infradead.org, will@kernel.org Subject: [PATCH v5 08/18] fault_inject: Don't rely on "return value" from WRITE_ONCE() Date: Mon, 11 May 2020 21:41:40 +0100 Message-Id: <20200511204150.27858-9-will@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200511204150.27858-1-will@kernel.org> References: <20200511204150.27858-1-will@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org It's a bit weird that WRITE_ONCE() evaluates to the value it stores and it's also different to smp_store_release(), which can't be used this way. In preparation for preventing this in WRITE_ONCE(), change the fault injection code to use a local variable instead. Cc: Akinobu Mita Signed-off-by: Will Deacon --- lib/fault-inject.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/lib/fault-inject.c b/lib/fault-inject.c index 8186ca84910b..ce12621b4275 100644 --- a/lib/fault-inject.c +++ b/lib/fault-inject.c @@ -106,7 +106,9 @@ bool should_fail(struct fault_attr *attr, ssize_t size) unsigned int fail_nth = READ_ONCE(current->fail_nth); if (fail_nth) { - if (!WRITE_ONCE(current->fail_nth, fail_nth - 1)) + fail_nth--; + WRITE_ONCE(current->fail_nth, fail_nth); + if (!fail_nth) goto fail; return false; -- 2.26.2.645.ge9eca65c58-goog