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,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 D1AEBC3F2CE for ; Wed, 4 Mar 2020 20:11:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A4BCB20870 for ; Wed, 4 Mar 2020 20:11:51 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="K6KX5X+v" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388064AbgCDULv (ORCPT ); Wed, 4 Mar 2020 15:11:51 -0500 Received: from us-smtp-2.mimecast.com ([205.139.110.61]:38495 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1728278AbgCDULu (ORCPT ); Wed, 4 Mar 2020 15:11:50 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1583352709; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=JkoOmo/uioqA9PwDxWS+txa/xYjNxgEGpUJZ05OzMY4=; b=K6KX5X+vYBhC14BIHKg7DroedXZhCjE7Xb9op0gyy09dwoAuXFhwdAQfHe+FGL9teXAfbt 4Du5AKf9DBp8IYS4zrvroE/qSM8Y9P/S/BmYzSB1501M5s3j5ma5B+ibrYvAEdlusEV77P PaRlpvZ4y8MfiJhaIcOIg2eD4k5rON8= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-402-wmTToPnyO0-fSYKc5-gz2w-1; Wed, 04 Mar 2020 15:11:46 -0500 X-MC-Unique: wmTToPnyO0-fSYKc5-gz2w-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id EFB2C8017DF; Wed, 4 Mar 2020 20:11:44 +0000 (UTC) Received: from colo-mx.corp.redhat.com (colo-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.21]) by smtp.corp.redhat.com (Postfix) with ESMTPS id BD00F27061; Wed, 4 Mar 2020 20:11:44 +0000 (UTC) Received: from zmail21.collab.prod.int.phx2.redhat.com (zmail21.collab.prod.int.phx2.redhat.com [10.5.83.24]) by colo-mx.corp.redhat.com (Postfix) with ESMTP id 7AA728446C; Wed, 4 Mar 2020 20:11:44 +0000 (UTC) Date: Wed, 4 Mar 2020 15:11:44 -0500 (EST) From: Vladis Dronov To: Andrea Righi Cc: Richard Cochran , "David S. Miller" , netdev@vger.kernel.org, linux-kernel@vger.kernel.org Message-ID: <1830360600.13123996.1583352704368.JavaMail.zimbra@redhat.com> In-Reply-To: <20200304175350.GB267906@xps-13> References: <20200304175350.GB267906@xps-13> Subject: Re: [PATCH] ptp: free ptp clock properly MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-Originating-IP: [10.40.204.205, 10.4.195.7] Thread-Topic: free ptp clock properly Thread-Index: PDXsSbboxZFT/a99TucbY86w37w5+g== X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Hello, Andrea, all, ----- Original Message ----- > From: "Andrea Righi" > Subject: [PATCH] ptp: free ptp clock properly > > There is a bug in ptp_clock_unregister() where ptp_clock_release() can > free up resources needed by posix_clock_unregister() to properly destroy > a related sysfs device. > > Fix this by calling posix_clock_unregister() in ptp_clock_release(). Honestly, this does not seem right. The calls at PTP clock release are: ptp_clock_unregister() -> posix_clock_unregister() -> cdev_device_del() -> -> ... bla ... -> ptp_clock_release() So, it looks like with this patch both posix_clock_unregister() and ptp_clock_release() are not called at all. And it looks like the "fix" is not removing PTP clock's cdev, i.e. leaking it and related sysfs resources. I would guess that a kernel in question (5.3.0-40-generic) has the commit a33121e5487b but does not have the commit 75718584cb3c, which should be exactly fixing a docking station disconnect crash. Could you please, check this? Why? We have 2 crash call traces. 1) the launchpad bug 2) the email which led to the commit 75718584cb3c creation (see Link:). Aaaaand they are identical starting from device_release_driver_internal() and almost to the top. > See also: > commit 75718584cb3c ("ptp: free ptp device pin descriptors properly"). > > BugLink: https://bugs.launchpad.net/bugs/1864754 > Fixes: a33121e5487b ("ptp: fix the race between the release of ptp_clock and > cdev") > Signed-off-by: Andrea Righi > --- > drivers/ptp/ptp_clock.c | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-) > > diff --git a/drivers/ptp/ptp_clock.c b/drivers/ptp/ptp_clock.c > index ac1f2bf9e888..12951023d0c6 100644 > --- a/drivers/ptp/ptp_clock.c > +++ b/drivers/ptp/ptp_clock.c > @@ -171,6 +171,7 @@ static void ptp_clock_release(struct device *dev) > struct ptp_clock *ptp = container_of(dev, struct ptp_clock, dev); > > ptp_cleanup_pin_groups(ptp); > + posix_clock_unregister(&ptp->clock); > mutex_destroy(&ptp->tsevq_mux); > mutex_destroy(&ptp->pincfg_mux); > ida_simple_remove(&ptp_clocks_map, ptp->index); > @@ -303,8 +304,6 @@ int ptp_clock_unregister(struct ptp_clock *ptp) > if (ptp->pps_source) > pps_unregister_source(ptp->pps_source); > > - posix_clock_unregister(&ptp->clock); > - > return 0; > } > EXPORT_SYMBOL(ptp_clock_unregister); > -- > 2.25.0 Best regards, Vladis Dronov | Red Hat, Inc. | The Core Kernel | Senior Software Engineer