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[2620:137:e000::1:20]) by mx.google.com with ESMTP id o6-20020a056a0015c600b0066886c86747si9074168pfu.310.2023.07.24.01.43.35; Mon, 24 Jul 2023 01:43:46 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@redhat.com header.s=mimecast20190719 header.b="WY0/jC75"; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231336AbjGXIJp (ORCPT + 99 others); Mon, 24 Jul 2023 04:09:45 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45412 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231335AbjGXIJn (ORCPT ); Mon, 24 Jul 2023 04:09:43 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E192B1BF for ; Mon, 24 Jul 2023 01:08:54 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1690186134; 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: in-reply-to:in-reply-to:references:references; bh=xhhWjOAo127IlI+J36ZFWJ4YvuZh0i268mYvp7khtFo=; b=WY0/jC75z6eUVcVGd0j8iub9w1ScDFDzqWN+psiHqcUfe8QAGuSPE6hfhVeF8lMgYVMjR1 ZAdXwFjbBc5TdV4z7Q289ms6ZfCRsplx9zPDOmfjz1Gz1WxtSXIE3Jl8UWpFiQkccJhRLA N+AQ6BOVq7J3waPJhlgJaJmC7ybcBFE= Received: from mimecast-mx02.redhat.com (66.187.233.73 [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-695-QHXgyZ0wOlaG5Vn_ZaG1gg-1; Mon, 24 Jul 2023 04:08:47 -0400 X-MC-Unique: QHXgyZ0wOlaG5Vn_ZaG1gg-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.rdu2.redhat.com [10.11.54.7]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 9E83429AA3B6; Mon, 24 Jul 2023 08:08:46 +0000 (UTC) Received: from localhost (ovpn-12-31.pek2.redhat.com [10.72.12.31]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 967751401C2E; Mon, 24 Jul 2023 08:08:45 +0000 (UTC) Date: Mon, 24 Jul 2023 16:08:41 +0800 From: Baoquan He To: David Hildenbrand Cc: Jiri Olsa , Lorenzo Stoakes , linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, Andrew Morton , Uladzislau Rezki , Matthew Wilcox , Liu Shixin , Jens Axboe , Alexander Viro Subject: Re: [PATCH v8 1/4] fs/proc/kcore: avoid bounce buffer for ktext data Message-ID: References: <86fd0ccb-f460-651f-8048-1026d905a2d6@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <86fd0ccb-f460-651f-8048-1026d905a2d6@redhat.com> X-Scanned-By: MIMEDefang 3.1 on 10.11.54.7 X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE, RCVD_IN_MSPIKE_H4,RCVD_IN_MSPIKE_WL,SPF_HELO_NONE,SPF_NONE, T_SCC_BODY_TEXT_LINE autolearn=unavailable autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 07/24/23 at 08:23am, David Hildenbrand wrote: > Hi, > > > > > I met this too when I executed below command to trigger a kcore reading. > > I wanted to do a simple testing during system running and got this. > > > > makedumpfile --mem-usage /proc/kcore > > > > Later I tried your above objdump testing, it corrupted system too. > > > > What do you mean with "corrupted system too" -- did it not only fail to > dump the system, but also actually harmed the system? From my testing, reading kcore will cause system panic, then reboot. Not sure if Jiri saw the same phenomenon. > > @Lorenzo do you plan on reproduce + fix, or should we consider reverting > that change? When tested on a arm64 system, the reproducution is stable. I will have a look too to see if I have some finding this week.