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[209.85.160.177]) by smtp.gmail.com with ESMTPSA id fp8-20020a05622a508800b003b6343a12adsm1283856qtb.90.2023.01.16.10.08.49 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 16 Jan 2023 10:08:49 -0800 (PST) Received: by mail-qt1-f177.google.com with SMTP id fd15so15313435qtb.9 for ; Mon, 16 Jan 2023 10:08:49 -0800 (PST) X-Received: by 2002:a05:622a:250f:b0:3b2:d164:a89b with SMTP id cm15-20020a05622a250f00b003b2d164a89bmr364175qtb.452.1673892068650; Mon, 16 Jan 2023 10:01:08 -0800 (PST) MIME-Version: 1.0 References: <1673235231-30302-1-git-send-email-byungchul.park@lge.com> In-Reply-To: <1673235231-30302-1-git-send-email-byungchul.park@lge.com> From: Linus Torvalds Date: Mon, 16 Jan 2023 10:00:52 -0800 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH RFC v7 00/23] DEPT(Dependency Tracker) To: Byungchul Park Cc: linux-kernel@vger.kernel.org, damien.lemoal@opensource.wdc.com, linux-ide@vger.kernel.org, adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org, mingo@redhat.com, peterz@infradead.org, will@kernel.org, tglx@linutronix.de, rostedt@goodmis.org, joel@joelfernandes.org, sashal@kernel.org, daniel.vetter@ffwll.ch, duyuyang@gmail.com, johannes.berg@intel.com, tj@kernel.org, tytso@mit.edu, willy@infradead.org, david@fromorbit.com, amir73il@gmail.com, gregkh@linuxfoundation.org, kernel-team@lge.com, linux-mm@kvack.org, akpm@linux-foundation.org, mhocko@kernel.org, minchan@kernel.org, hannes@cmpxchg.org, vdavydov.dev@gmail.com, sj@kernel.org, jglisse@redhat.com, dennis@kernel.org, cl@linux.com, penberg@kernel.org, rientjes@google.com, vbabka@suse.cz, ngupta@vflare.org, linux-block@vger.kernel.org, paolo.valente@linaro.org, josef@toxicpanda.com, linux-fsdevel@vger.kernel.org, viro@zeniv.linux.org.uk, jack@suse.cz, jlayton@kernel.org, dan.j.williams@intel.com, hch@infradead.org, djwong@kernel.org, dri-devel@lists.freedesktop.org, rodrigosiqueiramelo@gmail.com, melissa.srw@gmail.com, hamohammed.sa@gmail.com, 42.hyeyoo@gmail.com, chris.p.wilson@intel.com, gwan-gyeong.mun@intel.com Content-Type: text/plain; charset="UTF-8" X-Rspam-User: X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 1327A4001F X-Stat-Signature: sfc7d3rerjtya6kt6mgft3c4zzijk9cz X-HE-Tag: 1673892530-655979 X-HE-Meta: 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 33wygnAg DeTihFQ9sajmx2A9UpU6sNzpPA2cm+Utt6BMcC6rp8iDL7g/8Ggy/guAF05smqi5ZfiZqhpN/4Ynd7vZhtnwWYcwpYpI78nN6HaYsBPVcCvxfh1twhUIU1RXjwk01xn0jqWRSr4cZsq9B1VfeNi8qo31UhPFfc0jVmWEhkdGd9s/yImm5rKMzsvfgrUglM53VeRyivXTBh+6dBZPs/ifsb6zzKlJOxx6Re2xjwY2vWVM1HcEdPHxue5i+hRDb8DfhqCOLriHWmb8a1FFNdXAi4R9ADECBvtf6bH+5WFImuf0I9K8tvYyNckWPFa9SkAslod/OF5XIxDzD7/1iiuuMWowcFrVE3Lvna4Hg2mGW4v0N1sI= 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: [ Back from travel, so trying to make sense of this series.. ] On Sun, Jan 8, 2023 at 7:33 PM Byungchul Park wrote: > > I've been developing a tool for detecting deadlock possibilities by > tracking wait/event rather than lock(?) acquisition order to try to > cover all synchonization machanisms. It's done on v6.2-rc2. Ugh. I hate how this adds random patterns like if (timeout == MAX_SCHEDULE_TIMEOUT) sdt_might_sleep_strong(NULL); else sdt_might_sleep_strong_timeout(NULL); ... sdt_might_sleep_finish(); to various places, it seems so very odd and unmaintainable. I also recall this giving a fair amount of false positives, are they all fixed? Anyway, I'd really like the lockdep people to comment and be involved. We did have a fairly recent case of "lockdep doesn't track page lock dependencies because it fundamentally cannot" issue, so DEPT might fix those kinds of missing dependency analysis. See https://lore.kernel.org/lkml/00000000000060d41f05f139aa44@google.com/ for some context to that one, but at teh same time I would *really* want the lockdep people more involved and acking this work. Maybe I missed the email where you reported on things DEPT has found (and on the lack of false positives)? Linus