From 4617721c502b2ddaa4e324e86da4997edf738fa5 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 2 Sep 2026 09:55:01 -0400 Subject: ftrace: Synchronize the initialization of ftrace_ops There's some internal state that ftrace_ops needs to have set, but since it can be declared outside of the ftrace.c code, it calls ftrace_ops_init() on the ops in every global function. The issue is that if two tasks call it on the same ops at the same time it is possible to have the initialization of one corrupt the initialization of the other call. Create a ops_mutex to use to synchronize every initialization of the ftrace_ops. The mutex is taken within checking the ftrace_ops flag that states it was initializied but the flag is checked again after the mutex has been taken. Checking first outside the mutex allows it to shortcut having to take the mutex. But then the check needs to be done again after the mute is taken in case of races. Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20260902095501.6b59af20@gandalf.local.home Fixes: f04f24fb7e48d ("ftrace, kprobes: Fix a deadlock on ftrace_regex_lock") Reported-by: sashiko-bot@kernel.org Close: https://lore.kernel.org/all/20260829025528.49A831F000E9@smtp.kernel.org/ Signed-off-by: Steven Rostedt --- drivers/of/overlay_test.c | 120 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 120 insertions(+) create mode 100644 drivers/of/overlay_test.c (limited to 'drivers/of/overlay_test.c') diff --git a/drivers/of/overlay_test.c b/drivers/of/overlay_test.c new file mode 100644 index 000000000..c787524c5 --- /dev/null +++ b/drivers/of/overlay_test.c @@ -0,0 +1,120 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * KUnit tests for device tree overlays + */ +#include +#include +#include +#include +#include + +#include +#include + +#include "of_private.h" + +static const char * const kunit_node_name = "kunit-test"; +static const char * const kunit_compatible = "test,empty"; + +/* Test that of_overlay_apply_kunit() adds a node to the live tree */ +static void of_overlay_apply_kunit_apply(struct kunit *test) +{ + struct device_node *np; + + KUNIT_ASSERT_EQ(test, 0, + of_overlay_apply_kunit(test, kunit_overlay_test)); + + np = of_find_node_by_name(NULL, kunit_node_name); + KUNIT_EXPECT_NOT_ERR_OR_NULL(test, np); + of_node_put(np); +} + +/* + * Test that of_overlay_apply_kunit() creates platform devices with the + * expected device_node + */ +static void of_overlay_apply_kunit_platform_device(struct kunit *test) +{ + struct platform_device *pdev; + struct device_node *np; + + KUNIT_ASSERT_EQ(test, 0, + of_overlay_apply_kunit(test, kunit_overlay_test)); + + np = of_find_node_by_name(NULL, kunit_node_name); + of_node_put_kunit(test, np); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, np); + + pdev = of_find_device_by_node(np); + KUNIT_EXPECT_NOT_ERR_OR_NULL(test, pdev); + if (pdev) + put_device(&pdev->dev); +} + +static int of_overlay_bus_match_compatible(struct device *dev, const void *data) +{ + return of_device_is_compatible(dev->of_node, data); +} + +/* Test that of_overlay_apply_kunit() cleans up after the test is finished */ +static void of_overlay_apply_kunit_cleanup(struct kunit *test) +{ + struct kunit fake; + struct platform_device *pdev; + struct device *dev; + struct device_node *np; + + of_root_kunit_skip(test); + if (!IS_ENABLED(CONFIG_OF_OVERLAY)) + kunit_skip(test, "requires CONFIG_OF_OVERLAY to apply overlay"); + if (!IS_ENABLED(CONFIG_OF_EARLY_FLATTREE)) + kunit_skip(test, "requires CONFIG_OF_EARLY_FLATTREE for root node"); + + kunit_init_test(&fake, "fake test", NULL); + KUNIT_ASSERT_EQ(test, fake.status, KUNIT_SUCCESS); + + KUNIT_ASSERT_EQ(test, 0, + of_overlay_apply_kunit(&fake, kunit_overlay_test)); + + np = of_find_node_by_name(NULL, kunit_node_name); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, np); + of_node_put_kunit(&fake, np); + + pdev = of_find_device_by_node(np); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, pdev); + put_device(&pdev->dev); /* Not derefing 'pdev' after this */ + + /* Remove overlay */ + kunit_cleanup(&fake); + + /* The node and device should be removed */ + np = of_find_node_by_name(NULL, kunit_node_name); + KUNIT_EXPECT_PTR_EQ(test, NULL, np); + of_node_put(np); + + dev = bus_find_device(&platform_bus_type, NULL, kunit_compatible, + of_overlay_bus_match_compatible); + KUNIT_EXPECT_PTR_EQ(test, NULL, dev); + put_device(dev); +} + +static struct kunit_case of_overlay_apply_kunit_test_cases[] = { + KUNIT_CASE(of_overlay_apply_kunit_apply), + KUNIT_CASE(of_overlay_apply_kunit_platform_device), + KUNIT_CASE(of_overlay_apply_kunit_cleanup), + {} +}; + +/* + * Test suite for test managed device tree overlays. + */ +static struct kunit_suite of_overlay_apply_kunit_suite = { + .name = "of_overlay_apply_kunit", + .test_cases = of_overlay_apply_kunit_test_cases, +}; + +kunit_test_suites( + &of_overlay_apply_kunit_suite, +); +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("KUnit tests for device tree overlays"); -- cgit v1.3.1