2 Commits

Author	SHA1	Message	Date
Brian Norris	5b65258229	genirq/test: Resolve irq lock inversion warnings ... irq_shutdown_and_deactivate() is normally called with the descriptor lock held, and interrupts disabled. Nested a few levels down, it grabs the global irq_resend_lock. Lockdep rightfully complains when interrupts are not disabled: CPU0 CPU1 ---- ---- lock(irq_resend_lock); local_irq_disable(); lock(&irq_desc_lock_class); lock(irq_resend_lock); <Interrupt> lock(&irq_desc_lock_class); ... _raw_spin_lock+0x2b/0x40 clear_irq_resend+0x14/0x70 irq_shutdown_and_deactivate+0x29/0x80 irq_shutdown_depth_test+0x1ce/0x600 kunit_try_run_case+0x90/0x120 Grab the descriptor lock and disable interrupts, to resolve the problem. Fixes: 66067c3c8a ("genirq: Add kunit tests for depth counts") Reported-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Brian Norris <briannorris@chromium.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Guenter Roeck <linux@roeck-us.net> Link: https://lore.kernel.org/all/aJJONEIoIiTSDMqc@google.com Closes: https://lore.kernel.org/lkml/31a761e4-8f81-40cf-aaf5-d220ba11911c@roeck-us.net/	2025-08-06 10:29:48 +02:00
Brian Norris	66067c3c8a	genirq: Add kunit tests for depth counts ... There have been a few bugs and/or misunderstandings about the reference counting, and startup/shutdown behaviors in the IRQ core and related CPU hotplug code. These 4 test cases try to capture a few interesting cases. * irq_disable_depth_test: basic request/disable/enable sequence * irq_free_disabled_test: request/disable/free/re-request sequence - this catches errors on previous revisions of my work * irq_cpuhotplug_test: exercises managed-affinity IRQ + CPU hotplug. This captures a problematic test case which was fixed recently. This test requires CONFIG_SMP and a hotpluggable CPU#1. * irq_shutdown_depth_test: exercises similar behavior from irq_cpuhotplug_test, but directly using irq_*() APIs instead of going through CPU hotplug. This still requires CONFIG_SMP, because managed-affinity is stubbed out (and not all APIs are even present) without it. Note the use of 'imply SMP': ARCH=um doesn't support SMP, and kunit is often exercised there. Thus, 'imply' will force SMP on where possible (such as ARCH=x86_64), but leave it off where it's not. Behavior on various SMP and ARCH configurations: $ tools/testing/kunit/kunit.py run 'irq_test_cases*' --arch x86_64 --qemu_args '-smp 2' [...] [11:12:24] Testing complete. Ran 4 tests: passed: 4 $ tools/testing/kunit/kunit.py run 'irq_test_cases*' --arch x86_64 [...] [11:13:27] [SKIPPED] irq_cpuhotplug_test [11:13:27] ================= [PASSED] irq_test_cases ================== [11:13:27] ============================================================ [11:13:27] Testing complete. Ran 4 tests: passed: 3, skipped: 1 # default: ARCH=um $ tools/testing/kunit/kunit.py run 'irq_test_cases*' [11:14:26] [SKIPPED] irq_shutdown_depth_test [11:14:26] [SKIPPED] irq_cpuhotplug_test [11:14:26] ================= [PASSED] irq_test_cases ================== [11:14:26] ============================================================ [11:14:26] Testing complete. Ran 4 tests: passed: 2, skipped: 2 Without commit 788019eb55 ("genirq: Retain disable depth for managed interrupts across CPU hotplug"), this fails as follows: [11:18:55] =============== irq_test_cases (4 subtests) ================ [11:18:55] [PASSED] irq_disable_depth_test [11:18:55] [PASSED] irq_free_disabled_test [11:18:55] # irq_shutdown_depth_test: EXPECTATION FAILED at kernel/irq/irq_test.c:147 [11:18:55] Expected desc->depth == 1, but [11:18:55] desc->depth == 0 (0x0) [11:18:55] ------------[ cut here ]------------ [11:18:55] Unbalanced enable for IRQ 26 [11:18:55] WARNING: CPU: 1 PID: 36 at kernel/irq/manage.c:792 __enable_irq+0x36/0x60 ... [11:18:55] [FAILED] irq_shutdown_depth_test [11:18:55] #1 [11:18:55] # irq_cpuhotplug_test: EXPECTATION FAILED at kernel/irq/irq_test.c:202 [11:18:55] Expected irqd_is_activated(data) to be false, but is true [11:18:55] # irq_cpuhotplug_test: EXPECTATION FAILED at kernel/irq/irq_test.c:203 [11:18:55] Expected irqd_is_started(data) to be false, but is true [11:18:55] # irq_cpuhotplug_test: EXPECTATION FAILED at kernel/irq/irq_test.c:204 [11:18:55] Expected desc->depth == 1, but [11:18:55] desc->depth == 0 (0x0) [11:18:55] ------------[ cut here ]------------ [11:18:55] Unbalanced enable for IRQ 27 [11:18:55] WARNING: CPU: 0 PID: 38 at kernel/irq/manage.c:792 __enable_irq+0x36/0x60 ... [11:18:55] [FAILED] irq_cpuhotplug_test [11:18:55] # module: irq_test [11:18:55] # irq_test_cases: pass:2 fail:2 skip:0 total:4 [11:18:55] # Totals: pass:2 fail:2 skip:0 total:4 [11:18:55] ================= [FAILED] irq_test_cases ================== [11:18:55] ============================================================ [11:18:55] Testing complete. Ran 4 tests: passed: 2, failed: 2 Signed-off-by: Brian Norris <briannorris@chromium.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/all/20250522210837.4135244-1-briannorris@chromium.org	2025-06-13 15:24:44 +02:00