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[2003:cb:c723:4c00:5c85:5575:c321:cea3]) by smtp.gmail.com with ESMTPSA id z10-20020a1c4c0a000000b003fe2397c17fsm2352867wmf.17.2023.07.31.12.24.50 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 31 Jul 2023 12:24:51 -0700 (PDT) Message-ID: <32b8c5e4-c8e3-0244-1b1a-ca33bd44f38a@redhat.com> Date: Mon, 31 Jul 2023 21:24:50 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.13.0 Subject: Re: [PATCH v8 1/4] fs/proc/kcore: avoid bounce buffer for ktext data Content-Language: en-US To: Lorenzo Stoakes 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 References: <86fd0ccb-f460-651f-8048-1026d905a2d6@redhat.com> From: David Hildenbrand Organization: Red Hat In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Spam-Status: No, score=-2.2 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,NICE_REPLY_A, RCVD_IN_DNSWL_BLOCKED,RCVD_IN_MSPIKE_H4,RCVD_IN_MSPIKE_WL, SPF_HELO_NONE,SPF_NONE,T_SCC_BODY_TEXT_LINE autolearn=ham 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 31.07.23 21:21, Lorenzo Stoakes wrote: > 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. > I spotted https://lkml.kernel.org/r/069dd40aa71e634b414d07039d72467d051fb486.camel@gmx.de today, maybe that's related. -- Cheers, David / dhildenb