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[2a02:3100:ad43:d501:2c28:bb72:120d:420e]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-4a1fd0f4427sm90362275e9.3.2026.10.21.22.17.48 (version=TLS1_3 cipher=TLS_CHACHA20_POLY1305_SHA256 bits=256/256); Wed, 21 Oct 2026 22:17:50 -0700 (PDT) From: Karl Mehltretter To: Steven Rostedt , Peter Zijlstra , Thomas Gleixner Cc: Karl Mehltretter , Catalin Marinas , Will Deacon , Mark Rutland , Ingo Molnar , Andy Lutomirski , Frederic Weisbecker , "Paul E . McKenney" , Sebastian Andrzej Siewior , Boqun Feng , Waiman Long , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Ben Segall , Mel Gorman , Valentin Schneider , K Prateek Nayak , Hongyan Xia , Jonathan Corbet , Shuah Khan , Randy Dunlap , Andrew Morton , Nathan Chancellor , Nick Desaulniers , Bill Wendling , Justin Stitt , linux-arm-kernel@lists.infradead.org, linux-trace-kernel@vger.kernel.org, linux-rt-devel@lists.linux.dev, linux-doc@vger.kernel.org, llvm@lists.linux.dev, linux-kernel@vger.kernel.org Subject: [RFC PATCH 11/12] locking/selftest: Exercise hardirq return-tail preparation Date: Thu, 22 Oct 2026 07:16:53 +0200 Message-Id: <20261022051654.79224-12-kmehltretter@gmail.com> X-Mailer: git-send-email 2.39.5 (Apple Git-154) In-Reply-To: <20261022051654.79224-1-kmehltretter@gmail.com> References: <20261022051654.79224-1-kmehltretter@gmail.com> X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit The return-tail lockdep preparation must accept exactly one live hardirq context. Zero and nested contexts must fail, and the ordinary preparation helper must continue to reject a live hardirq context. Add focused boot-time lockdep cases for those four states. Skip the final IRQ-state transition after an expected preparation failure so that each failure remains attributable to the preparation invariant. Assisted-by: LLM --- lib/locking-selftest.c | 53 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 53 insertions(+) diff --git a/lib/locking-selftest.c b/lib/locking-selftest.c index c3d976c801bb4..1575a04f65d46 100644 --- a/lib/locking-selftest.c +++ b/lib/locking-selftest.c @@ -222,6 +222,55 @@ static void init_shared_classes(void) local_irq_enable(); \ local_bh_enable(); +static void irqtail_prepare_test_enter(unsigned int nr) +{ + unsigned int i; + + local_irq_disable(); + for (i = 0; i < nr; i++) + __irq_enter_raw(); + trace_hardirqs_on_prepare(); +} + +static void irqtail_prepare_test_exit(unsigned int nr) +{ + unsigned int i; + + for (i = 0; i < nr; i++) + __irq_exit_raw(); + if (debug_locks) + lockdep_hardirqs_on(_THIS_IP_); + raw_local_irq_enable(); +} + +static void prepare_irqtail_0(void) +{ + irqtail_prepare_test_enter(0); + lockdep_hardirqs_on_prepare_irqtail(); + irqtail_prepare_test_exit(0); +} + +static void prepare_irqtail_1(void) +{ + irqtail_prepare_test_enter(1); + lockdep_hardirqs_on_prepare_irqtail(); + irqtail_prepare_test_exit(1); +} + +static void prepare_irqtail_2(void) +{ + irqtail_prepare_test_enter(2); + lockdep_hardirqs_on_prepare_irqtail(); + irqtail_prepare_test_exit(2); +} + +static void prepare_regular_1(void) +{ + irqtail_prepare_test_enter(1); + lockdep_hardirqs_on_prepare(); + irqtail_prepare_test_exit(1); +} + /* * Shortcuts for lock/unlock API variants, to keep * the testcases compact: @@ -2934,6 +2983,10 @@ void locking_selftest(void) DO_TESTCASE_6x2x2RW("irq read-recursion", irq_read_recursion); DO_TESTCASE_6x2x2RW("irq read-recursion #2", irq_read_recursion2); DO_TESTCASE_6x2x2RW("irq read-recursion #3", irq_read_recursion3); + DO_TESTCASE_1B("IRQ tail prepare", prepare_irqtail, 0); + DO_TESTCASE_1("IRQ tail prepare", prepare_irqtail, 1); + DO_TESTCASE_1B("IRQ tail prepare", prepare_irqtail, 2); + DO_TESTCASE_1B("regular IRQ prepare", prepare_regular, 1); ww_tests(); -- 2.39.5 (Apple Git-154)