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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0CB9BC00140 for ; Sun, 21 Aug 2022 07:02:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229943AbiHUHB7 (ORCPT ); Sun, 21 Aug 2022 03:01:59 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50610 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229738AbiHUHBi (ORCPT ); Sun, 21 Aug 2022 03:01:38 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C45C92AC49; Sun, 21 Aug 2022 00:01:36 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id ECC64B80BA8; Sun, 21 Aug 2022 07:01:34 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1D1A8C433D6; Sun, 21 Aug 2022 07:01:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1661065293; bh=IkBhuQ4Ga0ENimbZcXbIIWSwXIVkLhO73dH4+EuA5qk=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=gaRiIVD//Qr759lieITGg0VK5y8wZHNrbBrROJxrwx7M8f0yQz3U3PklMmRWCJ2ac A/2TxsYoxPbDbFCMPf2cNq41YOSAOVZhklFeCGAZb/qHkk5y7eyqU93AD1oIStI8uV YjlV4MWCK0hySxeUQOkFco/U5bjU9gBtUYvMYTNo= Date: Sat, 20 Aug 2022 20:40:52 +0200 From: Greg Kroah-Hartman To: Heikki Krogerus , Takashi Iwai Cc: Linyu Yuan , linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [REGRESSION 5.19] NULL dereference by ucsi_acpi driver Message-ID: References: <87r11cmbx0.wl-tiwai@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87r11cmbx0.wl-tiwai@suse.de> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Aug 19, 2022 at 06:32:43PM +0200, Takashi Iwai wrote: > Hi, > > we've got multiple reports about 5.19 kernel starting crashing after > some time, and this turned out to be triggered by ucsi_acpi driver. > The details are found in: > https://bugzilla.suse.com/show_bug.cgi?id=1202386 > > The culprit seems to be the commit 87d0e2f41b8c > usb: typec: ucsi: add a common function ucsi_unregister_connectors() Adding Heikki to the thread... > > This commit looks as if it were a harmless cleanup, but this failed in > a subtle way. Namely, in the error scenario, the driver gets an error > at ucsi_register_altmodes(), and goes to the error handling to release > the resources. Through this refactoring, the release part was unified > to a funciton ucsi_unregister_connectors(). And there, it has a NULL > check of con->wq, and it bails out the loop if it's NULL. > Meanwhile, ucsi_register_port() itself still calls destroy_workqueue() > and clear con->wq at its error path. This ended up in the leftover > power supply device with the uninitialized / cleared device. > > It was confirmed that the problem could be avoided by a simple > revert. I'll be glad to revert this now, unless Heikki thinks: > > I guess another fix could be removing the part clearing con->wq, i.e. > > --- a/drivers/usb/typec/ucsi/ucsi.c > +++ b/drivers/usb/typec/ucsi/ucsi.c > @@ -1192,11 +1192,6 @@ static int ucsi_register_port(struct ucsi *ucsi, int index) > out_unlock: > mutex_unlock(&con->lock); > > - if (ret && con->wq) { > - destroy_workqueue(con->wq); > - con->wq = NULL; > - } > - > return ret; > } > > > ... but it's totally untested and I'm not entirely sure whether it's > better. that is any better? thanks, greg k-h