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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-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: C3F4340013 X-Stat-Signature: t3zfseirgmxgpfp1pbxaiosiyinmx7e7 X-Rspam-User: X-HE-Tag: 1690186133-933763 X-HE-Meta: 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 0oUdFTYX 33dEE3XntamrcWObNSyyjlFutWXm515ZihX8wlBkjYWe1KGIvPvqviVPcdprWtrWNX9V+TgUjVnK98uWSgGY0ohvJYU9zvsV+M0p4JeO/CjlZN6DtxL3PfcFZecV4PtEMh3GNF3VTHX9yyKNH8nqqGIYtl18w1gKocsqq X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: 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.