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[2003:c7:8f08:245:9964:4301:e0cc:477c]) by smtp.gmail.com with ESMTPSA id n20sm2824834wms.15.2021.08.26.10.34.05 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 26 Aug 2021 10:34:05 -0700 (PDT) Subject: Re: how to avoid CPU watchdog error during debug To: kernelnewbies@kernelnewbies.org References: <01cd01d7994d$6b063760$4112a620$@etri.re.kr> From: Philipp Hortmann Message-ID: <75ff22e0-d516-bec5-9b11-6dda30933359@gmail.com> Date: Thu, 26 Aug 2021 19:34:04 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.11.0 MIME-Version: 1.0 In-Reply-To: <01cd01d7994d$6b063760$4112a620$@etri.re.kr> Content-Language: en-US X-BeenThere: kernelnewbies@kernelnewbies.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Learn about the Linux kernel List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Errors-To: kernelnewbies-bounces@kernelnewbies.org On 8/25/21 3:06 AM, ckim@etri.re.kr wrote: > Hello, > > While debugging a kernel module, I get this error and the OS crashes. > > [39068.833652] rcu: INFO: rcu_sched self-detected stall on CPU > > [39068.834739] watchdog: BUG: soft lockup - CPU#3 stuck for 164s! > [systemd-journal:399] > > [39068.834854] watchdog: BUG: soft lockup - CPU#0 stuck for 164s! > [test_axpu_app:2896] > > This seems because I stopped the processor for debugging. > > How can I avoid this watchdog error during debug? > > Any help will be appreciated. Thanks! > > Chan Kim > > > _______________________________________________ > Kernelnewbies mailing list > Kernelnewbies@kernelnewbies.org > https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies > Hi Kim, since many things are time depending in the kernel it is difficult to stop parts of the kernel. The question is if it is really absolutely necessary to do this? Why you can not do it by logging with printk? Debugging is described in: https://www.doc-developpement-durable.org/file/Projets-informatiques/cours-&-manuels-informatiques/Linux/Linux%20Kernel%20Development,%203rd%20Edition.pdf See Chapter 18 Debugging Thanks! Bye Philipp _______________________________________________ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies