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From: Breno Leitao <leitao@debian.org>
To: Laxman Dewangan <ldewangan@nvidia.com>,
	Dmitry Osipenko <digetx@gmail.com>,
	Andi Shyti <andi.shyti@kernel.org>,
	Thierry Reding <thierry.reding@gmail.com>,
	Jonathan Hunter <jonathanh@nvidia.com>
Cc: paulmck@kernel.org,
	apopple@nvidia.com,
	Michael van der Westhuizen <rmikey@meta.com>,
	linux-i2c@vger.kernel.org (open list:I2C SUBSYSTEM HOST DRIVERS),
	linux-tegra@vger.kernel.org (open list:TEGRA ARCHITECTURE SUPPORT),
	linux-kernel@vger.kernel.org (open list)
Subject: [PATCH] [i2c-tegra] Do not mark ACPI devices as irq safe
Date: Thu,  6 Jun 2024 06:27:07 -0700
Message-ID: <20240606132708.1610308-1-leitao@debian.org>
Precedence: bulk
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit

On ACPI machines, the tegra i2c module encounters an issue due to a
mutex being called inside a spinlock. This leads to the following bug:

	BUG: sleeping function called from invalid context at kernel/locking/mutex.c:585
	in_atomic(): 0, irqs_disabled(): 1, non_block: 0, pid: 1282, name: kssif0010
	preempt_count: 0, expected: 0
	RCU nest depth: 0, expected: 0
	irq event stamp: 0

	Call trace:
	dump_backtrace+0xf0/0x140
	show_stack (./arch/x86/include/asm/current.h:49
		     arch/x86/kernel/dumpstack.c:312)
	dump_stack_lvl (lib/dump_stack.c:89 lib/dump_stack.c:115)
	dump_stack (lib/earlycpio.c:61)
	__might_resched (./arch/x86/include/asm/current.h:49
			 kernel/sched/core.c:10297)
	__might_sleep (./include/linux/lockdep.h:231
			 kernel/sched/core.c:10236)
	__mutex_lock_common+0x5c/0x2190
	mutex_lock_nested (kernel/locking/mutex.c:751)
	acpi_subsys_runtime_resume+0xb8/0x160
	__rpm_callback+0x1cc/0x4b0
	rpm_resume+0xa60/0x1078
	__pm_runtime_resume+0xbc/0x130
	tegra_i2c_xfer+0x74/0x398
	__i2c_transfer (./include/trace/events/i2c.h:122 drivers/i2c/i2c-core-base.c:2258)

The problem arises because during __pm_runtime_resume(), the spinlock
&dev->power.lock is acquired before rpm_resume() is called. Later,
rpm_resume() invokes acpi_subsys_runtime_resume(), which relies on
mutexes, triggering the error.

To address this issue, devices on ACPI are now marked as not IRQ-safe,
considering the dependency of acpi_subsys_runtime_resume() on mutexes.

Co-developed-by: Michael van der Westhuizen <rmikey@meta.com>
Signed-off-by: Michael van der Westhuizen <rmikey@meta.com>
Signed-off-by: Breno Leitao <leitao@debian.org>
---
 drivers/i2c/busses/i2c-tegra.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
index 85b31edc558d..6d783ecc3431 100644
--- a/drivers/i2c/busses/i2c-tegra.c
+++ b/drivers/i2c/busses/i2c-tegra.c
@@ -1804,7 +1804,7 @@ static int tegra_i2c_probe(struct platform_device *pdev)
 	 * VI I2C device shouldn't be marked as IRQ-safe because VI I2C won't
 	 * be used for atomic transfers.
 	 */
-	if (!IS_VI(i2c_dev))
+	if (!IS_VI(i2c_dev) && !ACPI_HANDLE(i2c_dev->dev))
 		pm_runtime_irq_safe(i2c_dev->dev);
 
 	pm_runtime_enable(i2c_dev->dev);
-- 
2.43.0