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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS 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 DC147C5ACD7 for ; Wed, 18 Mar 2020 10:12:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B3B3B2076C for ; Wed, 18 Mar 2020 10:12:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1584526365; bh=6Qp/xUEdfDHiwOlzFgHXZUcDvRvQ4RUplGy2llBeWXo=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=FULCliY3jGTr6wjBHydpxmSDDB4XUemhpTQ7zfP4JgsvEIxA8Ek7O6KAyJJy0ctOB VCR9uqF0axUepj4goM/JJSM8Pns7v1PawHwOLaIQgLZcVkyynhBy3to1aRyiZZVZQ8 tqgLzsB4Tuz9mL/ZWY18xjPzr+hP0cvoRu0wwTzM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727366AbgCRKMo (ORCPT ); Wed, 18 Mar 2020 06:12:44 -0400 Received: from mail.kernel.org ([198.145.29.99]:54362 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726310AbgCRKMo (ORCPT ); Wed, 18 Mar 2020 06:12:44 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 4663B20768; Wed, 18 Mar 2020 10:12:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1584526363; bh=6Qp/xUEdfDHiwOlzFgHXZUcDvRvQ4RUplGy2llBeWXo=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=pZHE5tlEzKgLpX+C7exwsPfM44nFiUWegCKqbBq8fYIx3Nr0wNC65Me80ZLTadDNo Ettdk6W3Z89nMnYoDSlz0B+Lw01hyCo/vC8D1n+pdbS2yWLHarWZjOgGHUGAAhVwhK cec0eWw3w3MA0yChNt1HntUFpLLiW15NzPAGLbC8= Date: Wed, 18 Mar 2020 11:12:40 +0100 From: Greg Kroah-Hartman To: Li Tao Cc: Felipe Balbi , =?utf-8?B?TWljaGHFgiBNaXJvc8WCYXc=?= , Sergey Organov , linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, wenhu.wang@vivo.com Subject: Re: [PATCH] usb: gadget: serial: Fixed KASAN null-ptr-deref in tty_wakeup Message-ID: <20200318101240.GA2067041@kroah.com> References: <20200318025606.2058-1-tao.li@vivo.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200318025606.2058-1-tao.li@vivo.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Mar 18, 2020 at 10:56:01AM +0800, Li Tao wrote: > The port->port.tty maybe reset as NULL, If gs_close() was invoked > unexpectedly during running gserial_connect(). > > BUG: KASAN: null-ptr-deref in tty_wakeup+0x1c/0x84 > Call trace: > [<0000000095c3c837>] dump_backtrace+0x0/0x6d4 > [<0000000047726bb8>] show_stack+0x18/0x20 > [<00000000bedb4c1e>] --dump_stack+0x20/0x28 > [<00000000722f2e2a>] dump_stack+0x84/0xb0 > [<00000000325683d4>] kasan_report_error+0x178/0x1e4 > [<0000000053079998>] kasan_report_error+0x0/0x1e4 > [<00000000b6d33afa>] --asan_load8+0x150/0x15c > [<00000000188745b8>] tty_wakeup+0x1c/0x84 > [<0000000064f6dd21>] gs_start_io+0xd0/0x11c > [<0000000063d67b6c>] gserial_connect+0x15c/0x1b0 > [<00000000faf7c0f9>] dm_set_alt+0xa8/0x190 > [<000000008deb1909>] composite_setup+0xde4/0x1edc > [<00000000792ee16d>] android_setup+0x210/0x294 > [<00000000ab32ef30>] dwc3_ep0_delegate_req+0x48/0x68 > [<0000000054e26fd2>] dwc3_ep0_interrupt+0xf2c/0x16fc > [<0000000050cb2262>] dwc3_interrupt+0x464/0x1f44 > [<00000000fdcaa6e9>] --handle_irq_event_percpu+0x184/0x398 > [<000000003b24ff56>] handle_irq_event_percpu+0xa0/0x134 > [<00000000aedda5ee>] handle_irq_event+0x60/0xa0 > [<000000005f51a570>] handle_fasteoi_irq+0x23c/0x31c > [<000000008db2608d>] generic_handle_irq+0x70/0xa4 > [<00000000098683fc>] --handle_domain_irq+0x84/0xe0 > [<000000008ed23b46>] gic_handle_irq+0x98/0xb8 > > Signed-off-by: Li Tao > --- > drivers/usb/gadget/function/u_serial.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/drivers/usb/gadget/function/u_serial.c b/drivers/usb/gadget/function/u_serial.c > index 8167d379e115..3c109a8f9ec4 100644 > --- a/drivers/usb/gadget/function/u_serial.c > +++ b/drivers/usb/gadget/function/u_serial.c > @@ -565,7 +565,8 @@ static int gs_start_io(struct gs_port *port) > gs_start_tx(port); > /* Unblock any pending writes into our circular buffer, in case > * we didn't in gs_start_tx() */ > - tty_wakeup(port->port.tty); > + if (port->port.tty) > + tty_wakeup(port->port.tty); What prevents port.tty from being set to NULL between the check and the call to tty_wakeup? Shouldn't gs_close() and gserial_connect() have some sort of locking to prevent this? thanks, greg k-h