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[82.17.115.212]) by smtp.gmail.com with ESMTPSA id a17-20020adffb91000000b0020c5253d907sm14249763wrr.83.2022.06.28.09.21.22 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 28 Jun 2022 09:21:22 -0700 (PDT) Date: Tue, 28 Jun 2022 17:21:22 +0100 From: Aaron Tomlin To: Steven Rostedt Cc: mcgrof@kernel.org, christophe.leroy@csgroup.eu, cl@linux.com, mbenes@suse.cz, akpm@linux-foundation.org, jeyu@kernel.org, linux-kernel@vger.kernel.org, linux-modules@vger.kernel.org, void@manifault.com, atomlin@atomlin.com, allen.lkml@gmail.com, joe@perches.com, msuchanek@suse.de, oleksandr@natalenko.name, jason.wessel@windriver.com, pmladek@suse.com, neelx@redhat.com, daniel.thompson@linaro.org, hch@infradead.org, Thomas Gleixner , linux-rt-users Subject: Re: [PATCH v11 10/14] module: kallsyms: Fix suspicious rcu usage Message-ID: <20220628162122.v7s3z24icwavur6y@ava.usersys.com> X-PGP-Key: http://pgp.mit.edu/pks/lookup?search=atomlin%40redhat.com X-PGP-Fingerprint: 7906 84EB FA8A 9638 8D1E 6E9B E2DE 9658 19CC 77D6 References: <20220310102413.3438665-1-atomlin@redhat.com> <20220310102413.3438665-11-atomlin@redhat.com> <20220627235612.4796c837@gandalf.local.home> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20220627235612.4796c837@gandalf.local.home> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon 2022-06-27 23:56 -0400, Steven Rostedt wrote: > > + preempt_enable(); > > ^^^^^^^^^^^^^^^^^ > > This just introduced an unbounded latency and will fail PREEMPT_RT. > Hi Steve, Sorry about that! If I understand correctly, there is absolutely no need to explicitly disable preemption in this context. I will use: rcu_read_lock() and rcu_read_unlock(), respectively, which will then be suitable for the preemptible RCU implementation. Kind regards, -- Aaron Tomlin