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[103.168.172.201]) by smtp.gmail.com with ESMTPSA id d75a77b69052e-47377e24400sm5295041cf.41.2025.02.24.19.55.31 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 24 Feb 2025 19:55:32 -0800 (PST) Received: from phl-compute-09.internal (phl-compute-09.phl.internal [10.202.2.49]) by mailfauth.phl.internal (Postfix) with ESMTP id C8CDF1200043; Mon, 24 Feb 2025 22:55:31 -0500 (EST) Received: from phl-mailfrontend-02 ([10.202.2.163]) by phl-compute-09.internal (MEProxy); Mon, 24 Feb 2025 22:55:31 -0500 X-ME-Sender: X-ME-Received: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgeefvddrtddtgdektdeiiecutefuodetggdotefrod ftvfcurfhrohhfihhlvgemucfhrghsthforghilhdpggftfghnshhusghstghrihgsvgdp uffrtefokffrpgfnqfghnecuuegrihhlohhuthemuceftddtnecusecvtfgvtghiphhivg hnthhsucdlqddutddtmdenucfjughrpefhvfevufffkffojghfggfgsedtkeertdertddt necuhfhrohhmpeeuohhquhhnucfhvghnghcuoegsohhquhhnrdhfvghnghesghhmrghilh drtghomheqnecuggftrfgrthhtvghrnhepgeeljeeitdehvdehgefgjeevfeejjeekgfev ffeiueejhfeuiefggeeuheeggefgnecuvehluhhsthgvrhfuihiivgeptdenucfrrghrrg hmpehmrghilhhfrhhomhepsghoqhhunhdomhgvshhmthhprghuthhhphgvrhhsohhnrghl ihhthidqieelvdeghedtieegqddujeejkeehheehvddqsghoqhhunhdrfhgvnhhgpeepgh hmrghilhdrtghomhesfhhigihmvgdrnhgrmhgvpdhnsggprhgtphhtthhopeeftddpmhho uggvpehsmhhtphhouhhtpdhrtghpthhtoheprhgtuhesvhhgvghrrdhkvghrnhgvlhdroh hrghdprhgtphhtthhopehprghulhhmtghksehkvghrnhgvlhdrohhrghdprhgtphhtthho pehfrhgvuggvrhhitgeskhgvrhhnvghlrdhorhhgpdhrtghpthhtohepnhgvvghrrghjrd huphgrughhhigrhieskhgvrhhnvghlrdhorhhgpdhrtghpthhtohepjhhovghlsehjohgv lhhfvghrnhgrnhguvghsrdhorhhgpdhrtghpthhtohepjhhoshhhsehjohhshhhtrhhiph hlvghtthdrohhrghdprhgtphhtthhopegsohhquhhnrdhfvghnghesghhmrghilhdrtgho mhdprhgtphhtthhopehurhgviihkihesghhmrghilhdrtghomhdprhgtphhtthhopehroh hsthgvughtsehgohhoughmihhsrdhorhhg X-ME-Proxy: Feedback-ID: iad51458e:Fastmail Received: by mail.messagingengine.com (Postfix) with ESMTPA; Mon, 24 Feb 2025 22:55:31 -0500 (EST) From: Boqun Feng To: rcu@vger.kernel.org Cc: "Paul E. McKenney" , Frederic Weisbecker , Neeraj Upadhyay , Joel Fernandes , Josh Triplett , Boqun Feng , Uladzislau Rezki , Steven Rostedt , Mathieu Desnoyers , Lai Jiangshan , Zqiang , Davidlohr Bueso , Ingo Molnar , Peter Zijlstra , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Ben Segall , Mel Gorman , Valentin Schneider , Masami Hiramatsu , Shuah Khan , Sebastian Andrzej Siewior , Clark Williams , linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-rt-devel@lists.linux.dev, Ankur Arora Subject: [PATCH rcu 08/11] rcutorture: Update ->extendables check for lazy preemption Date: Mon, 24 Feb 2025 19:55:13 -0800 Message-Id: <20250225035516.26443-9-boqun.feng@gmail.com> X-Mailer: git-send-email 2.39.5 (Apple Git-154) In-Reply-To: <20250225035516.26443-1-boqun.feng@gmail.com> References: <20250225035516.26443-1-boqun.feng@gmail.com> Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 The rcutorture_one_extend_check() function's second last check assumes that "preempt_count() & PREEMPT_MASK" is non-zero only if RCUTORTURE_RDR_PREEMPT or RCUTORTURE_RDR_SCHED bit is set. This works for preemptible RCU and for non-preemptible RCU running in a non-preemptible kernel. But it fails for non-preemptible RCU running in a preemptible kernel because then rcu_read_lock() is just preempt_disable(), which increases preempt count. This commit therefore adjusts this check to take into account the case fo non-preemptible RCU running in a preemptible kernel. Reviewed-by: Paul E. McKenney Signed-off-by: Boqun Feng --- kernel/rcu/rcutorture.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c index 280bff706017..4cae119dece8 100644 --- a/kernel/rcu/rcutorture.c +++ b/kernel/rcu/rcutorture.c @@ -1901,8 +1901,16 @@ static void rcutorture_one_extend_check(char *s, int curstate, int new, int old, WARN_ONCE(cur_ops->extendables && !(curstate & (RCUTORTURE_RDR_BH | RCUTORTURE_RDR_RBH)) && (preempt_count() & SOFTIRQ_MASK), ROEC_ARGS); - WARN_ONCE(cur_ops->extendables && - !(curstate & (RCUTORTURE_RDR_PREEMPT | RCUTORTURE_RDR_SCHED)) && + + /* + * non-preemptible RCU in a preemptible kernel uses preempt_disable() + * as rcu_read_lock(). + */ + mask = RCUTORTURE_RDR_PREEMPT | RCUTORTURE_RDR_SCHED; + if (!IS_ENABLED(CONFIG_PREEMPT_RCU)) + mask |= RCUTORTURE_RDR_RCU_1 | RCUTORTURE_RDR_RCU_2; + + WARN_ONCE(cur_ops->extendables && !(curstate & mask) && (preempt_count() & PREEMPT_MASK), ROEC_ARGS); /*