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=-18.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 1A039C433ED for ; Thu, 15 Apr 2021 15:06:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EC90561027 for ; Thu, 15 Apr 2021 15:06:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233630AbhDOPHB (ORCPT ); Thu, 15 Apr 2021 11:07:01 -0400 Received: from mail.kernel.org ([198.145.29.99]:47212 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234467AbhDOO7D (ORCPT ); Thu, 15 Apr 2021 10:59:03 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id BDD5C613E9; Thu, 15 Apr 2021 14:55:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1618498518; bh=Wf2FfQRqE2IqdzcST8irF0YQSNcDyoNPvp0MkCI9NNw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=de31XrqgNoXqgjQcKEkaPl0lIPwIum0UEoYdZp5F5EWf473A1jLBc5ZM1YSAMooUl g5CosN979+D9ryGvzvwFK7zHljz5UDuE56yYKI3szN3IwfeZcHy1DjEE7ulYne9yr/ O12x5iydc+MbfzHB5xcgWbaUcZWJZyGwAR9drPWs= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Lukasz Majczak , Lukasz Bartosik , Stephen Boyd , Sasha Levin Subject: [PATCH 4.14 33/68] clk: fix invalid usage of list cursor in unregister Date: Thu, 15 Apr 2021 16:47:14 +0200 Message-Id: <20210415144415.544188331@linuxfoundation.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210415144414.464797272@linuxfoundation.org> References: <20210415144414.464797272@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Lukasz Bartosik [ Upstream commit 7045465500e465b09f09d6e5bdc260a9f1aab97b ] Fix invalid usage of a list_for_each_entry cursor in clk_notifier_unregister(). When list is empty or if the list is completely traversed (without breaking from the loop on one of the entries) then the list cursor does not point to a valid entry and therefore should not be used. The patch fixes a logical bug that hasn't been seen in pratice however it is analogus to the bug fixed in clk_notifier_register(). The issue was dicovered when running 5.12-rc1 kernel on x86_64 with KASAN enabled: BUG: KASAN: global-out-of-bounds in clk_notifier_register+0xab/0x230 Read of size 8 at addr ffffffffa0d10588 by task swapper/0/1 CPU: 1 PID: 1 Comm: swapper/0 Not tainted 5.12.0-rc1 #1 Hardware name: Google Caroline/Caroline, BIOS Google_Caroline.7820.430.0 07/20/2018 Call Trace: dump_stack+0xee/0x15c print_address_description+0x1e/0x2dc kasan_report+0x188/0x1ce ? clk_notifier_register+0xab/0x230 ? clk_prepare_lock+0x15/0x7b ? clk_notifier_register+0xab/0x230 clk_notifier_register+0xab/0x230 dw8250_probe+0xc01/0x10d4 ... Memory state around the buggy address: ffffffffa0d10480: 00 00 00 00 00 03 f9 f9 f9 f9 f9 f9 00 00 00 00 ffffffffa0d10500: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 f9 f9 >ffffffffa0d10580: f9 f9 f9 f9 00 00 00 00 00 00 00 00 00 00 00 00 ^ ffffffffa0d10600: 00 00 00 00 00 00 f9 f9 f9 f9 f9 f9 00 00 00 00 ffffffffa0d10680: 00 00 00 00 00 00 00 00 f9 f9 f9 f9 00 00 00 00 ================================================================== Fixes: b2476490ef11 ("clk: introduce the common clock framework") Reported-by: Lukasz Majczak Signed-off-by: Lukasz Bartosik Link: https://lore.kernel.org/r/20210401225149.18826-2-lb@semihalf.com Signed-off-by: Stephen Boyd Signed-off-by: Sasha Levin --- drivers/clk/clk.c | 30 +++++++++++++----------------- 1 file changed, 13 insertions(+), 17 deletions(-) diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c index a0807482ebce..971a9a5006af 100644 --- a/drivers/clk/clk.c +++ b/drivers/clk/clk.c @@ -3055,32 +3055,28 @@ EXPORT_SYMBOL_GPL(clk_notifier_register); */ int clk_notifier_unregister(struct clk *clk, struct notifier_block *nb) { - struct clk_notifier *cn = NULL; - int ret = -EINVAL; + struct clk_notifier *cn; + int ret = -ENOENT; if (!clk || !nb) return -EINVAL; clk_prepare_lock(); - list_for_each_entry(cn, &clk_notifier_list, node) - if (cn->clk == clk) - break; - - if (cn->clk == clk) { - ret = srcu_notifier_chain_unregister(&cn->notifier_head, nb); + list_for_each_entry(cn, &clk_notifier_list, node) { + if (cn->clk == clk) { + ret = srcu_notifier_chain_unregister(&cn->notifier_head, nb); - clk->core->notifier_count--; + clk->core->notifier_count--; - /* XXX the notifier code should handle this better */ - if (!cn->notifier_head.head) { - srcu_cleanup_notifier_head(&cn->notifier_head); - list_del(&cn->node); - kfree(cn); + /* XXX the notifier code should handle this better */ + if (!cn->notifier_head.head) { + srcu_cleanup_notifier_head(&cn->notifier_head); + list_del(&cn->node); + kfree(cn); + } + break; } - - } else { - ret = -ENOENT; } clk_prepare_unlock(); -- 2.30.2