linux-kernel - [tip: irq/urgent] genirq/test: Resolve irq lock inversion warnings

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Message-ID: <175446920768.1420.10144196712187691411.tip-bot2@tip-bot2>
Date: Wed, 06 Aug 2025 08:33:27 -0000
From: "tip-bot2 for Brian Norris" <tip-bot2@...utronix.de>
To: linux-tip-commits@...r.kernel.org
Cc: Guenter Roeck <linux@...ck-us.net>,
 Brian Norris <briannorris@...omium.org>, Thomas Gleixner <tglx@...utronix.de>,
 x86@...nel.org, linux-kernel@...r.kernel.org, maz@...nel.org
Subject: [tip: irq/urgent] genirq/test: Resolve irq lock inversion warnings

The following commit has been merged into the irq/urgent branch of tip:

Commit-ID:     5b65258229117995eb6c4bd74995e15fb5f2cfe3
Gitweb:        https://git.kernel.org/tip/5b65258229117995eb6c4bd74995e15fb5f2cfe3
Author:        Brian Norris <briannorris@...omium.org>
AuthorDate:    Tue, 05 Aug 2025 11:32:20 -07:00
Committer:     Thomas Gleixner <tglx@...utronix.de>
CommitterDate: Wed, 06 Aug 2025 10:29:48 +02:00

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: 66067c3c8a1e ("genirq: Add kunit tests for depth counts")
Reported-by: Guenter Roeck <linux@...ck-us.net>
Signed-off-by: Brian Norris <briannorris@...omium.org>
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Tested-by: Guenter Roeck <linux@...ck-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/
---
 kernel/irq/irq_test.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/kernel/irq/irq_test.c b/kernel/irq/irq_test.c
index 5161b56..a75abeb 100644
--- a/kernel/irq/irq_test.c
+++ b/kernel/irq/irq_test.c
@@ -1,5 +1,6 @@
 // SPDX-License-Identifier: LGPL-2.1+
 
+#include <linux/cleanup.h>
 #include <linux/cpu.h>
 #include <linux/cpumask.h>
 #include <linux/interrupt.h>
@@ -134,7 +135,8 @@ static void irq_shutdown_depth_test(struct kunit *test)
 	disable_irq(virq);
 	KUNIT_EXPECT_EQ(test, desc->depth, 1);
 
-	irq_shutdown_and_deactivate(desc);
+	scoped_guard(raw_spinlock_irqsave, &desc->lock)
+		irq_shutdown_and_deactivate(desc);
 
 	KUNIT_EXPECT_FALSE(test, irqd_is_activated(data));
 	KUNIT_EXPECT_FALSE(test, irqd_is_started(data));