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[172.10.233.147]) by smtp.gmail.com with ESMTPSA id m13sm925823otf.43.2020.07.23.16.11.39 (version=TLS1 cipher=ECDHE-ECDSA-AES128-SHA bits=128/128); Thu, 23 Jul 2020 16:11:40 -0700 (PDT) Date: Thu, 23 Jul 2020 16:11:27 -0700 (PDT) From: Hugh Dickins X-X-Sender: hugh@eggly.anvils To: Linus Torvalds cc: Oleg Nesterov , Hugh Dickins , Michal Hocko , Linux-MM , LKML , Andrew Morton , Tim Chen , Michal Hocko Subject: Re: [RFC PATCH] mm: silence soft lockups from unlock_page In-Reply-To: Message-ID: References: <20200721063258.17140-1-mhocko@kernel.org> <20200723124749.GA7428@redhat.com> User-Agent: Alpine 2.11 (LSU 23 2013-08-11) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-Rspamd-Queue-Id: 7A3AC1801FA2A X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam03 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 Thu, 23 Jul 2020, Linus Torvalds wrote: > > I'll send a new version after I actually test it. I'll give it a try when you're happy with it. I did try yesterday's with my swapping loads on home machines (3 of 4 survived 16 hours), and with some google stresstests on work machines (0 of 10 survived). I've not spent long analyzing the crashes, all of them in or below __wake_up_common() called from __wake_up_locked_key_bookmark(): sometimes gets to run the curr->func() and crashes on something inside there (often list_del's lib/list_debug.c:53!), sometimes cannot get that far. Looks like the wait queue entries on the list were not entirely safe with that patch. Hugh