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 BD2F7C001E0 for ; Mon, 31 Jul 2023 19:21:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231516AbjGaTVj (ORCPT ); Mon, 31 Jul 2023 15:21:39 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53564 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229776AbjGaTVi (ORCPT ); Mon, 31 Jul 2023 15:21:38 -0400 Received: from mail-wr1-x42e.google.com (mail-wr1-x42e.google.com [IPv6:2a00:1450:4864:20::42e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 93E6DE5F; Mon, 31 Jul 2023 12:21:35 -0700 (PDT) Received: by mail-wr1-x42e.google.com with SMTP id ffacd0b85a97d-31297125334so3334330f8f.0; Mon, 31 Jul 2023 12:21:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20221208; t=1690831294; x=1691436094; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=1On/KiRyE9vftggERFLzh8PS8Zt/RkJXfV5TSxkZ7ec=; b=F+W8OGdxSzu8BC0xALV8+qGARtWLmhFnrSS/3SIIB3afnud+usI+Ab1CiSRhjo2HM0 xqwymACj2ixZvQtvimKzVzexF+ETcZLMXlqRc3HZXRpxb8/Io+TRv3tjO8C3/hOi7vds exZiQucHo15paHqoBpJKbI3hbPubHLECK9VF3TNUbFSfmTKwsUVjC3rnuyBmodDnoTBl TONTeRasQmEgfoseekDndPcaUzy5tXMb5ul+FlKCr5w3rxF1lLbg/axacBWvhFPhpVoC fsZRVKcMxvrDH4C6J3wTx92rsSICtVy6c11F3ANAQkBNuq8/rqM1sKfHFbB0bqGX5dyW 8Nbg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1690831294; x=1691436094; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=1On/KiRyE9vftggERFLzh8PS8Zt/RkJXfV5TSxkZ7ec=; b=Jlv8lF4QBr0Qg0pp4atIbTN6n84DXymi5z3u9f9qoloTugKt3+Mv5iTVEsIM6TUbV6 +SUSvNgA7wEyxtXE27iJr/sN3QWpZ06+7J6KlLTLjEHz0hSMiNeznsYjtHIj9dp2KCPz G6bDQ3MiCkuruQbnNVHFY87KkXnwqtfkqgkKebEO+C5iQNphUvuuENNZ3tSsMzik/LDT mYxLO4EmzEc/JyZh9rrAI9epTBeWq+32sxfRcBqlueXYRNTrFf14HF1G1KamwrIWJnDM QUxg9JQnUTOsJjOSeSoW29N5/l7V+AHr6RcupZ8l+41emkOG+3aOgSWdumQc8xy5hDqO x0VQ== X-Gm-Message-State: ABy/qLbUlQEfE7OyR08CHuuotNsLu73fVPHR/irXyJR5Z5rdv3TgvoSj fu91AapKlBOQAW5+EOG7xXY= X-Google-Smtp-Source: APBJJlHOaPMTFdzeZ1MhBed2PMj/5baagWzIaktNXum9X1zi+9to9ASFG6lc0F9cJ7+UGb7I4Paq4A== X-Received: by 2002:adf:d84f:0:b0:317:5cfb:44c7 with SMTP id k15-20020adfd84f000000b003175cfb44c7mr491514wrl.30.1690831293771; Mon, 31 Jul 2023 12:21:33 -0700 (PDT) Received: from localhost ([2a00:23c5:dc8c:8701:1663:9a35:5a7b:1d76]) by smtp.gmail.com with ESMTPSA id e5-20020a5d5005000000b00311d8c2561bsm13808194wrt.60.2023.07.31.12.21.32 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 31 Jul 2023 12:21:33 -0700 (PDT) Date: Mon, 31 Jul 2023 20:21:32 +0100 From: Lorenzo Stoakes To: David Hildenbrand Cc: Baoquan He , Jiri Olsa , 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> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jul 24, 2023 at 08:23:55AM +0200, 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? > > @Lorenzo do you plan on reproduce + fix, or should we consider reverting > that change? > > -- > Cheers, > > David / dhildenb > Apologies I mised this, I have been very busy lately not least with book :) Concerning, I will take a look as I get a chance. I think the whole series would have to be reverted which would be... depressing... as other patches in series eliminates the bounce buffer altogether.