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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 933D9C001B0 for ; Mon, 24 Jul 2023 08:09:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231334AbjGXIJn (ORCPT ); Mon, 24 Jul 2023 04:09:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45400 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230423AbjGXIJl (ORCPT ); Mon, 24 Jul 2023 04:09:41 -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 E7894FE for ; Mon, 24 Jul 2023 01:08:53 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1690186133; 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=inKVkj4SLnDwuuJykk2NXxDqHlsH6JJthGPq+dLes6KLoN7BiAdkFudvxKyFf7jdga87C1 1PvjgdJN+hqiM5RcJZIfOxAKm77didrDTgk9xm/YdABObowX9TM6GbPc6iX/C//lRbR9G3 QaNcq6Fq7xbkP/yC2Z6ecoqo/v96csM= 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 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@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.