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[71.184.117.43]) by smtp.gmail.com with ESMTPSA id i25sm6765898qkk.30.2019.10.08.05.00.43 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 08 Oct 2019 05:00:43 -0700 (PDT) Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: quoted-printable From: Qian Cai Mime-Version: 1.0 (1.0) Subject: Re: [PATCH v2] mm/page_isolation: fix a deadlock with printk() Date: Tue, 8 Oct 2019 08:00:43 -0400 Message-Id: <3836DE34-9DD2-4815-9E1E-CB87D881B9AD@lca.pw> References: <20191008103907.GE6681@dhcp22.suse.cz> Cc: Petr Mladek , akpm@linux-foundation.org, sergey.senozhatsky.work@gmail.com, rostedt@goodmis.org, peterz@infradead.org, linux-mm@kvack.org, john.ogness@linutronix.de, david@redhat.com, linux-kernel@vger.kernel.org In-Reply-To: <20191008103907.GE6681@dhcp22.suse.cz> To: Michal Hocko X-Mailer: iPhone Mail (17A860) X-Bogosity: Ham, tests=bogofilter, spamicity=0.000794, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: > On Oct 8, 2019, at 6:39 AM, Michal Hocko wrote: >=20 > Have you actually triggered any real deadlock? With a zone->lock in > place it would be pretty clear with hard lockups detected. Yes, I did trigger here and there, and those lockdep splats are especially u= seful to figure out why.=