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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> X-Rspam-User: X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: D5CBC4002A X-Stat-Signature: dtk8smruy4ag7xtimzfmf86mz3seskx8 X-HE-Tag: 1690831294-96836 X-HE-Meta: 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 W2CBGedM yJmmEdBs347GYHLxsleKwGh4eoMxms3omAL2gnI+t5FiTTBV4RVcSLf76tbQSCnXSCRu19eFzgWBtZIWXvIA9PMsBphasPurjUoOL1BUADYM+XLLGDQcqgyoHzADOpguK53V2++LY132ovx0NwPgZTmfyuIqJHTgnJhJquMAy4nLINmFZyRx+4amQ78hboFhbtm1443oogWwDrn4jV9IM0skHBAsQQrJ7tig89iFSrJhxf+ARfqjn9oyl/GdwAh5G78jNmFbjpdbusUyPriXV4X03zloNUyPNRLbi9S6p1J08M6EHHdGmGDyN+vxMLKed18zUQjGnGTLISgBIVWZJOatY1R1NylRIUO3L77dkF0vXZNt0EukKrF0lqwNtXPBizqnnLnfj9ltaC8E= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000001, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: 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.