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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id A1652C10F1A for ; Thu, 9 May 2024 15:30:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=574nJBK9z7dCiAzOWHwVN3JwEsDjGTgPAsi8wwtsKCI=; b=LKVWg4apWmIhuW UwqScX6uwnf2sfoK1sKT5npNK+m61ku8Ih4efA897rQyCu6YsgIfwHAbkCFy4KmRBMNYiQMzQXMB+ WjAANDLoBl6vL7Zq8cdhQl5MD+QX3NttZiz58BuEWju03NnOzvABseTUBQmrEakHS1dtWdNGV7zHx NUL8fOrmJaRT+vM8/QwqI8fNliLRFyY/w+wWjGYAc6Zv0+fNiGj72jGiST/TpA4w6OVT2A/8Nr9kN hyzXU6+LpCUAL9liDDB0Atj/hTI1n9BOeDyChbFbm9fmGDHwVjTFKv6ZyLVghpUigLP2YC4c/Gvm0 JXs7EZ89+HNHcEYs2sbQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1s55j6-00000001tf1-3NvA; Thu, 09 May 2024 15:30:32 +0000 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by bombadil.infradead.org with esmtps (Exim 4.97.1 #2 (Red Hat Linux)) id 1s55j3-00000001teY-0dqd for kexec@lists.infradead.org; Thu, 09 May 2024 15:30:30 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1715268627; 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=Hy/b3d3gFNZGN9o/TMf1nXsT/S7nrlG2+f6fAjptoCk=; b=e63c5sAnrNGZAXIyH3b6Bp3tIWoBxLeYeo3t8rq5HzjIjalPquMK6roIpEWfOx/jtSgdGQ yU8i4aq5ichbi+bHQX15uZ7zT7x7O2N6RkzDTOI+Y7D96CUAz1u1P7C0Ocuy4qYRlbklo5 nESYRKbY6QZk6zQYapmPxCUxvYgh0ok= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-378-lBH72HkKPEu-T6_GN-WWuA-1; Thu, 09 May 2024 11:30:24 -0400 X-MC-Unique: lBH72HkKPEu-T6_GN-WWuA-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.rdu2.redhat.com [10.11.54.4]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 562671816ED2; Thu, 9 May 2024 15:30:23 +0000 (UTC) Received: from localhost (unknown [10.72.116.38]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 48D5220C5662; Thu, 9 May 2024 15:30:21 +0000 (UTC) Date: Thu, 9 May 2024 23:30:19 +0800 From: Baoquan He To: Rik van Riel Cc: akpm@linux-foundation.org, Vivek Goyal , Dave Young , kexec@lists.infradead.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, kernel-team@meta.com Subject: Re: [PATCH] fs/proc: fix softlockup in __read_vmcore Message-ID: References: <20240507091858.36ff767f@imladris.surriel.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.4 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240509_083029_495996_5C17884D X-CRM114-Status: GOOD ( 22.12 ) X-BeenThere: kexec@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Sender: "kexec" Errors-To: kexec-bounces+kexec=archiver.kernel.org@lists.infradead.org On 05/09/24 at 09:41am, Rik van Riel wrote: > On Thu, 2024-05-09 at 11:52 +0800, Baoquan He wrote: > > Hi, > > = > > On 05/07/24 at 09:18am, Rik van Riel wrote: > > > While taking a kernel core dump with makedumpfile on a larger > > > system, > > > softlockup messages often appear. > > > = > > > While softlockup warnings can be harmless, they can also interfere > > > with things like RCU freeing memory, which can be problematic when > > > the kdump kexec image is configured with as little memory as > > > possible. > > > = > > > Avoid the softlockup, and give things like work items and RCU a > > > chance to do their thing during __read_vmcore by adding a > > > cond_resched. > > = > > Thanks for fixing this. > > = > > By the way, is it easy to reproduce? And should we add some trace of > > the > > softlockup into log so that people can search for it and confirm when > > encountering it? > = > It is pretty easy to reproduce, but it does not happen all the time. > With millions of systems, even rare errors are common :) > = > However, we have been running with this fix for long enough (we > deployed it in order to test it) that I don't think we have the=A0 > warning stored any more. Those logs were rotated out long ago. OK, thanks for the explanation. Acked-by: Baoquan He _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec