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=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=no 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 126D3C00523 for ; Sun, 5 Jan 2020 23:11:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E05512085B for ; Sun, 5 Jan 2020 23:11:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727237AbgAEXL0 (ORCPT ); Sun, 5 Jan 2020 18:11:26 -0500 Received: from shards.monkeyblade.net ([23.128.96.9]:42566 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726494AbgAEXL0 (ORCPT ); Sun, 5 Jan 2020 18:11:26 -0500 Received: from localhost (unknown [IPv6:2601:601:9f00:1c3::3d5]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) (Authenticated sender: davem-davemloft) by shards.monkeyblade.net (Postfix) with ESMTPSA id BD52C15714135; Sun, 5 Jan 2020 15:11:25 -0800 (PST) Date: Sun, 05 Jan 2020 15:11:25 -0800 (PST) Message-Id: <20200105.151125.1541050812175137787.davem@davemloft.net> To: sboyd@kernel.org Cc: linux-kernel@vger.kernel.org, netdev@vger.kernel.org, nicolas.ferre@microchip.com, yash.shah@sifive.com, linux@roeck-us.net Subject: Re: [PATCH] macb: Don't unregister clks unconditionally From: David Miller In-Reply-To: <20200104001921.225529-1-sboyd@kernel.org> References: <20200104001921.225529-1-sboyd@kernel.org> X-Mailer: Mew version 6.8 on Emacs 26.1 Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.5.12 (shards.monkeyblade.net [149.20.54.216]); Sun, 05 Jan 2020 15:11:26 -0800 (PST) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Stephen Boyd Date: Fri, 3 Jan 2020 16:19:21 -0800 > The only clk init function in this driver that register a clk is > fu540_c000_clk_init(), and thus we need to unregister the clk when this > driver is removed on that platform. Other init functions, for example > macb_clk_init(), don't register clks and therefore we shouldn't > unregister the clks when this driver is removed. Convert this > registration path to devm so it gets auto-unregistered when this driver > is removed and drop the clk_unregister() calls in driver remove (and > error paths) so that we don't erroneously remove a clk from the system > that isn't registered by this driver. > > Otherwise we get strange crashes with a use-after-free when the > devm_clk_get() call in macb_clk_init() calls clk_put() on a clk pointer > that has become invalid because it is freed in clk_unregister(). > > Cc: Nicolas Ferre > Cc: Yash Shah > Reported-by: Guenter Roeck > Fixes: c218ad559020 ("macb: Add support for SiFive FU540-C000") > Signed-off-by: Stephen Boyd Applied and queued up for -stable, thanks.