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([2601:188:c100:5710:627d:9ff:fe85:9ade]) by smtp.gmail.com with ESMTPSA id 586e51a60fabf-2bd1d8fb86dsm525430fac.4.2025.02.19.12.20.39 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 19 Feb 2025 12:20:40 -0800 (PST) From: Waiman Long X-Google-Original-From: Waiman Long Message-ID: <8ca57548-4b18-401d-bfda-95bc12216adf@redhat.com> Date: Wed, 19 Feb 2025 15:20:39 -0500 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 0/2] hung_task: Dump the blocking task stacktrace To: Lance Yang , mhiramat@kernel.org Cc: Peter Zijlstra , Ingo Molnar , Will Deacon , Andrew Morton , Boqun Feng , Joel Granados , Anna Schumaker , Kent Overstreet , Yongliang Gao , Steven Rostedt , Tomasz Figa , Sergey Senozhatsky , linux-kernel@vger.kernel.org, Linux Memory Management List References: <173997003868.2137198.9462617208992136056.stgit@mhiramat.tok.corp.google.com> In-Reply-To: X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: FtP9jk9cISXOsmvJWpgFP3lLU2wvH4il82iF-83V-2E_1739996442 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Stat-Signature: wph1enjcckqteh3zbke7pcy1iwooe7b5 X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 52CC5160008 X-Rspam-User: X-HE-Tag: 1739996445-695913 X-HE-Meta: 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 XipsXxCn 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000039, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 2/19/25 10:02 AM, Lance Yang wrote: > On Wed, Feb 19, 2025 at 9:33 PM Lance Yang wrote: >> CC linux-mm >> >> On Wed, Feb 19, 2025 at 9:00 PM Masami Hiramatsu (Google) >> wrote: >>> Hi, >>> >>> The hung_task detector is very useful for detecting the lockup. >>> However, since it only dumps the blocked (uninterruptible sleep) >>> processes, it is not enough to identify the root cause of that >>> lockup. >>> >>> For example, if a process holds a mutex and sleep an event in >>> interruptible state long time, the other processes will wait on >>> the mutex in uninterruptible state. In this case, the waiter >>> processes are dumped, but the blocker process is not shown >>> because it is sleep in interruptible state. > Cool! I just ran into something similar today, but with rwsem. In that > case, the blocked process was locked up, and we could not identify > the root cause either ;( Once this patch series is settled down, we can extend rwsem to provide similar feature. Cheers, Longman