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https://git.kernel.org/pub/scm/libs/libgpiod/libgpiod.git
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0a552e7908
A bug was recently discovered in the kernel that can result in the edge event fifo not being correctly initialised and stack contents being returned in edge events. The trigger for the bug is requesting a line with debounce, but not edge detection, and then reconfiguring the line to enable edge detection. Add a test case that triggers the bug. This will fail on kernels that do not contain the fix for the bug. The test is located in a new test file, tests-kernel-uapi.c, intended to contain tests specifically testing some aspect of the kernel uAPI, not libgpiod itself. Signed-off-by: Kent Gibson <warthog618@gmail.com> Link: https://lore.kernel.org/r/20240513160031.309139-1-warthog618@gmail.com Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
112 lines
3.6 KiB
C
112 lines
3.6 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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// SPDX-FileCopyrightText: 2024 Kent Gibson <warthog618@gmail.com>
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#include <glib.h>
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#include <gpiod.h>
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#include <poll.h>
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#include "gpiod-test.h"
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#include "gpiod-test-helpers.h"
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#include "gpiod-test-sim.h"
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#define GPIOD_TEST_GROUP "kernel-uapi"
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static gpointer falling_and_rising_edge_events(gpointer data)
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{
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GPIOSimChip *sim = data;
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/*
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* needs to be as long as several system timer ticks or resulting
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* pulse width is unreliable and may get filtered by debounce.
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*/
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g_usleep(50000);
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g_gpiosim_chip_set_pull(sim, 2, G_GPIOSIM_PULL_UP);
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g_usleep(50000);
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g_gpiosim_chip_set_pull(sim, 2, G_GPIOSIM_PULL_DOWN);
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return NULL;
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}
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GPIOD_TEST_CASE(enable_debounce_then_edge_detection)
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{
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static const guint offset = 2;
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g_autoptr(GPIOSimChip) sim = g_gpiosim_chip_new("num-lines", 8, NULL);
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g_autoptr(struct_gpiod_chip) chip = NULL;
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g_autoptr(struct_gpiod_line_settings) settings = NULL;
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g_autoptr(struct_gpiod_line_config) line_cfg = NULL;
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g_autoptr(struct_gpiod_line_request) request = NULL;
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g_autoptr(GThread) thread = NULL;
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g_autoptr(struct_gpiod_edge_event_buffer) buffer = NULL;
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struct gpiod_edge_event *event;
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guint64 ts_rising, ts_falling;
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gint ret;
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chip = gpiod_test_open_chip_or_fail(g_gpiosim_chip_get_dev_path(sim));
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settings = gpiod_test_create_line_settings_or_fail();
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line_cfg = gpiod_test_create_line_config_or_fail();
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buffer = gpiod_test_create_edge_event_buffer_or_fail(64);
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gpiod_line_settings_set_direction(settings, GPIOD_LINE_DIRECTION_INPUT);
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gpiod_line_settings_set_debounce_period_us(settings, 10);
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gpiod_test_line_config_add_line_settings_or_fail(line_cfg, &offset, 1,
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settings);
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request = gpiod_test_chip_request_lines_or_fail(chip, NULL, line_cfg);
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gpiod_line_settings_set_edge_detection(settings, GPIOD_LINE_EDGE_BOTH);
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gpiod_test_line_config_add_line_settings_or_fail(line_cfg, &offset, 1,
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settings);
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gpiod_test_line_request_reconfigure_lines_or_fail(request, line_cfg);
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thread = g_thread_new("request-release",
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falling_and_rising_edge_events, sim);
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g_thread_ref(thread);
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/* First event. */
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ret = gpiod_line_request_wait_edge_events(request, 1000000000);
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g_assert_cmpint(ret, >, 0);
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gpiod_test_join_thread_and_return_if_failed(thread);
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ret = gpiod_line_request_read_edge_events(request, buffer, 1);
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g_assert_cmpint(ret, ==, 1);
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gpiod_test_join_thread_and_return_if_failed(thread);
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g_assert_cmpuint(gpiod_edge_event_buffer_get_num_events(buffer), ==, 1);
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event = gpiod_edge_event_buffer_get_event(buffer, 0);
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g_assert_nonnull(event);
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gpiod_test_join_thread_and_return_if_failed(thread);
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g_assert_cmpint(gpiod_edge_event_get_event_type(event), ==,
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GPIOD_EDGE_EVENT_RISING_EDGE);
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g_assert_cmpuint(gpiod_edge_event_get_line_offset(event), ==, 2);
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ts_rising = gpiod_edge_event_get_timestamp_ns(event);
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/* Second event. */
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ret = gpiod_line_request_wait_edge_events(request, 1000000000);
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g_assert_cmpint(ret, >, 0);
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gpiod_test_join_thread_and_return_if_failed(thread);
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ret = gpiod_line_request_read_edge_events(request, buffer, 1);
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g_assert_cmpint(ret, ==, 1);
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gpiod_test_join_thread_and_return_if_failed(thread);
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g_assert_cmpuint(gpiod_edge_event_buffer_get_num_events(buffer), ==, 1);
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event = gpiod_edge_event_buffer_get_event(buffer, 0);
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g_assert_nonnull(event);
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gpiod_test_join_thread_and_return_if_failed(thread);
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g_assert_cmpint(gpiod_edge_event_get_event_type(event), ==,
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GPIOD_EDGE_EVENT_FALLING_EDGE);
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g_assert_cmpuint(gpiod_edge_event_get_line_offset(event), ==, 2);
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ts_falling = gpiod_edge_event_get_timestamp_ns(event);
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g_thread_join(thread);
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g_assert_cmpuint(ts_falling, >, ts_rising);
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}
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