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The test-klp-callbacks script includes a few tests which rely on kernel task timings that may not always execute as expected under system load. These may generate out of sequence kernel log messages that result in test failure. Instead of using sleep timing windows to orchestrate these tests, add a block_transition module parameter to communicate the test purpose and utilize flush_queue() to serialize the test module's task output. Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com> Reviewed-by: Petr Mladek <pmladek@suse.com> Acked-by: Miroslav Benes <mbenes@suse.cz> Signed-off-by: Petr Mladek <pmladek@suse.com> Link: https://lore.kernel.org/r/20200603182058.109470-2-ycote@redhat.com
62 lines
1.5 KiB
C
62 lines
1.5 KiB
C
// SPDX-License-Identifier: GPL-2.0
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// Copyright (C) 2018 Joe Lawrence <joe.lawrence@redhat.com>
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/sched.h>
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#include <linux/workqueue.h>
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#include <linux/delay.h>
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/* load/run-time control from sysfs writer */
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static bool block_transition;
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module_param(block_transition, bool, 0644);
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MODULE_PARM_DESC(block_transition, "block_transition (default=false)");
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static void busymod_work_func(struct work_struct *work);
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static DECLARE_WORK(work, busymod_work_func);
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static void busymod_work_func(struct work_struct *work)
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{
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pr_info("%s enter\n", __func__);
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while (READ_ONCE(block_transition)) {
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/*
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* Busy-wait until the sysfs writer has acknowledged a
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* blocked transition and clears the flag.
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*/
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msleep(20);
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}
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pr_info("%s exit\n", __func__);
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}
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static int test_klp_callbacks_busy_init(void)
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{
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pr_info("%s\n", __func__);
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schedule_work(&work);
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if (!block_transition) {
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/*
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* Serialize output: print all messages from the work
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* function before returning from init().
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*/
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flush_work(&work);
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}
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return 0;
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}
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static void test_klp_callbacks_busy_exit(void)
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{
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WRITE_ONCE(block_transition, false);
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flush_work(&work);
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pr_info("%s\n", __func__);
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}
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module_init(test_klp_callbacks_busy_init);
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module_exit(test_klp_callbacks_busy_exit);
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Joe Lawrence <joe.lawrence@redhat.com>");
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MODULE_DESCRIPTION("Livepatch test: busy target module");
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