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=-6.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,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 085CDC47094 for ; Thu, 10 Jun 2021 13:58:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DA7E2613F8 for ; Thu, 10 Jun 2021 13:58:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230431AbhFJOAX (ORCPT ); Thu, 10 Jun 2021 10:00:23 -0400 Received: from mail.kernel.org ([198.145.29.99]:59416 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230394AbhFJOAX (ORCPT ); Thu, 10 Jun 2021 10:00:23 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 8FD53613E9; Thu, 10 Jun 2021 13:58:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1623333506; bh=o++3xiZX3nMKu7aNY5ckTg0Ma0hfr6symUJjbkUzZ+U=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=PnXVFEttj/jz1gHw7etoLfFBOTe/Lc7wtUnngDaV+3ELMy2jHpJ4v7/GXTjtN+T0D OKQgNjnCBmXaQiFK47fXeXzNwnYqhOo2Y9rp45oSi7Ev4QMRmGGnYZWNgGsJNaw4Qj BPw/QyJSjOn3LkocSqfIILTVemS0FgTlV7wFvssguapHp21D7HeCHRP3ClkOK7tqL2 mE/tlTpKQNQ+17rh61QQf8qTb8qkqofA6NPSeu8ZeSLLWmgzr6NYDmA58NnspYsAZV JPP0xDeVWXiRw4vxfgMTzC7fUj5bJru04wXB8GS1PLHMnFYa2dq1sScIZqYjYfSw0r nkKXg+XPNwHcw== Date: Thu, 10 Jun 2021 21:58:22 +0800 From: Peter Chen To: Greg Kroah-Hartman Cc: balbi@kernel.org, Jack Pham , linux-usb@vger.kernel.org Subject: Re: [PATCH 1/1] usb: dwc3: core: fix kernel panic when do reboot Message-ID: <20210610135822.GA7839@Peter> References: <20210608105656.10795-1-peter.chen@kernel.org> <20210608164933.GA2601@jackp-linux.qualcomm.com> <20210610020047.GB6592@nchen> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org On 21-06-10 08:36:57, Greg Kroah-Hartman wrote: > On Thu, Jun 10, 2021 at 10:00:47AM +0800, Peter Chen wrote: > > On 21-06-09 11:42:53, Greg Kroah-Hartman wrote: > > > On Wed, Jun 09, 2021 at 11:01:07AM +0200, Greg Kroah-Hartman wrote: > > > > On Tue, Jun 08, 2021 at 09:50:01AM -0700, Jack Pham wrote: > > > > > Hi Peter, > > > > > > > > > > On Tue, Jun 08, 2021 at 06:56:56PM +0800, Peter Chen wrote: > > > > > > When do system reboot, it calls dwc3_shutdown and the whole debugfs > > > > > > for dwc3 has removed first, when the gadget tries to do deinit, and > > > > > > remove debugfs for its endpoints, it meets NULL pointer dereference > > > > > > issue when call debugfs_lookup. Fix it by removing the whole dwc3 > > > > > > debugfs later than dwc3_drd_exit. > > > > > > > > > > Ouch, thanks for catching this! I think in your previous reply[1] you > > > > > did warn about the debugfs_remove_recursive() getting called twice, but > > > > > it seems here the issue is due to the debugfs_lookup() getting called on > > > > > a stale dwc->root pointer after it was already removed. > > > > > > > > We can also fix this by getting rid of that "root" pointer as it's > > > > useless (we can look it up if we need it.) I'll send a patch later to > > > > do that, as it's a good idea to do anyway, and is independant of this > > > > fix. > > > > > > Now sent: > > > https://lore.kernel.org/r/20210609093924.3293230-1-gregkh@linuxfoundation.org > > > > Hi Felipe, > > > > With Greg above patch, this issue is fixed indirectly. I don't think my patch is > > needed, do you think so? > > Which patch is "your patch" here? > The patch in this thread. -- Thanks, Peter Chen