linux-kernel - Re: drivers/base/power/runtime-test.c:22 pm_runtime_depth_test() warn: pm_runtime_get

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Message-ID: <aWFLZJxddp0b3bkS@google.com>
Date: Fri, 9 Jan 2026 10:39:32 -0800
From: Brian Norris <briannorris@...omium.org>
To: Dan Carpenter <dan.carpenter@...aro.org>
Cc: oe-kbuild@...ts.linux.dev, lkp@...el.com, oe-kbuild-all@...ts.linux.dev,
	linux-kernel@...r.kernel.org,
	"Rafael J. Wysocki" <rjw@...ysocki.net>
Subject: Re: drivers/base/power/runtime-test.c:22 pm_runtime_depth_test()
 warn: pm_runtime_get_sync() also returns 1 on success

On Fri, Jan 09, 2026 at 02:02:09PM +0300, Dan Carpenter wrote:
> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
> head:   623fb9912f6af600cda3b6bd166ac738c1115ef4
> commit: 7f7acd193ba8aaa8ed07cfadc335bb17a991fd42 PM: runtime: Add basic kunit tests for API contracts
> config: x86_64-randconfig-161-20260109 (https://download.01.org/0day-ci/archive/20260109/202601091832.YueBSiOb-lkp@intel.com/config)
> compiler: gcc-14 (Debian 14.2.0-19) 14.2.0
> smatch version: v0.5.0-8985-g2614ff1a
> 
> If you fix the issue in a separate patch/commit (i.e. not just a new version of
> the same patch/commit), kindly add following tags
> | Reported-by: kernel test robot <lkp@...el.com>
> | Reported-by: Dan Carpenter <dan.carpenter@...aro.org>
> | Closes: https://lore.kernel.org/r/202601091832.YueBSiOb-lkp@intel.com/
> 
> New smatch warnings:
> drivers/base/power/runtime-test.c:22 pm_runtime_depth_test() warn: pm_runtime_get_sync() also returns 1 on success
> drivers/base/power/runtime-test.c:78 pm_runtime_idle_test() warn: pm_runtime_get_sync() also returns 1 on success
> drivers/base/power/runtime-test.c:182 pm_runtime_error_test() warn: pm_runtime_get_sync() also returns 1 on success
> 
> Old smatch warnings:
> drivers/base/power/runtime-test.c:185 pm_runtime_error_test() warn: pm_runtime_get_sync() also returns 1 on success

FWIW, these are all false positives. These are unit tests which are
purposely exercising the return codes of this notably-complex API under
controlled conditions.

Brian

> vim +22 drivers/base/power/runtime-test.c
> 
> 7f7acd193ba8aa Brian Norris 2025-09-25   13  static void pm_runtime_depth_test(struct kunit *test)
> 7f7acd193ba8aa Brian Norris 2025-09-25   14  {
> 7f7acd193ba8aa Brian Norris 2025-09-25   15  	struct device *dev = kunit_device_register(test, DEVICE_NAME);
> 7f7acd193ba8aa Brian Norris 2025-09-25   16  
> 7f7acd193ba8aa Brian Norris 2025-09-25   17  	KUNIT_ASSERT_PTR_NE(test, NULL, dev);
> 7f7acd193ba8aa Brian Norris 2025-09-25   18  
> 7f7acd193ba8aa Brian Norris 2025-09-25   19  	pm_runtime_enable(dev);
> 7f7acd193ba8aa Brian Norris 2025-09-25   20  
> 7f7acd193ba8aa Brian Norris 2025-09-25   21  	KUNIT_EXPECT_TRUE(test, pm_runtime_suspended(dev));
> 7f7acd193ba8aa Brian Norris 2025-09-25  @22  	KUNIT_EXPECT_EQ(test, 0, pm_runtime_get_sync(dev));
> 
> Use pm_runtime_resume_and_get()?
> 
> 7f7acd193ba8aa Brian Norris 2025-09-25   23  	KUNIT_EXPECT_TRUE(test, pm_runtime_active(dev));
> 7f7acd193ba8aa Brian Norris 2025-09-25   24  	KUNIT_EXPECT_EQ(test, 1, pm_runtime_get_sync(dev)); /* "already active" */
> 7f7acd193ba8aa Brian Norris 2025-09-25   25  	KUNIT_EXPECT_EQ(test, 0, pm_runtime_put_sync(dev));
> 7f7acd193ba8aa Brian Norris 2025-09-25   26  	KUNIT_EXPECT_EQ(test, 0, pm_runtime_put_sync(dev));
> 7f7acd193ba8aa Brian Norris 2025-09-25   27  	KUNIT_EXPECT_TRUE(test, pm_runtime_suspended(dev));
> 7f7acd193ba8aa Brian Norris 2025-09-25   28  }
>