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1eb69ded80
KUnit's try-catch infrastructure now uses vfork_done, which is always
set to a valid completion when a kthread is created, but which is set to
NULL once the thread terminates. This creates a race condition, where
the kthread exits before we can wait on it.
Keep a copy of vfork_done, which is taken before we wake_up_process()
and so valid, and wait on that instead.
Fixes: 93533996100c ("kunit: Handle test faults")
Reported-by: Linux Kernel Functional Testing <lkft@linaro.org>
Closes: https://lore.kernel.org/lkml/20240410102710.35911-1-naresh.kamboju@linaro.org/
Tested-by: Linux Kernel Functional Testing <lkft@linaro.org>
Acked-by: Mickaël Salaün <mic@digikod.net>
Signed-off-by: David Gow <davidgow@google.com>
Reviewed-by: Rae Moar <rmoar@google.com>
Tested-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
117 lines
3.4 KiB
C
117 lines
3.4 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* An API to allow a function, that may fail, to be executed, and recover in a
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* controlled manner.
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*
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* Copyright (C) 2019, Google LLC.
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* Author: Brendan Higgins <brendanhiggins@google.com>
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*/
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#include <kunit/test.h>
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#include <linux/completion.h>
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#include <linux/kernel.h>
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#include <linux/kthread.h>
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#include <linux/sched/task.h>
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#include "try-catch-impl.h"
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void __noreturn kunit_try_catch_throw(struct kunit_try_catch *try_catch)
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{
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try_catch->try_result = -EFAULT;
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kthread_exit(0);
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}
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EXPORT_SYMBOL_GPL(kunit_try_catch_throw);
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static int kunit_generic_run_threadfn_adapter(void *data)
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{
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struct kunit_try_catch *try_catch = data;
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try_catch->try_result = -EINTR;
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try_catch->try(try_catch->context);
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if (try_catch->try_result == -EINTR)
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try_catch->try_result = 0;
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return 0;
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}
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static unsigned long kunit_test_timeout(void)
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{
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/*
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* TODO(brendanhiggins@google.com): We should probably have some type of
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* variable timeout here. The only question is what that timeout value
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* should be.
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*
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* The intention has always been, at some point, to be able to label
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* tests with some type of size bucket (unit/small, integration/medium,
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* large/system/end-to-end, etc), where each size bucket would get a
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* default timeout value kind of like what Bazel does:
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* https://docs.bazel.build/versions/master/be/common-definitions.html#test.size
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* There is still some debate to be had on exactly how we do this. (For
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* one, we probably want to have some sort of test runner level
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* timeout.)
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*
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* For more background on this topic, see:
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* https://mike-bland.com/2011/11/01/small-medium-large.html
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*
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* If tests timeout due to exceeding sysctl_hung_task_timeout_secs,
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* the task will be killed and an oops generated.
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*/
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return 300 * msecs_to_jiffies(MSEC_PER_SEC); /* 5 min */
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}
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void kunit_try_catch_run(struct kunit_try_catch *try_catch, void *context)
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{
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struct kunit *test = try_catch->test;
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struct task_struct *task_struct;
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struct completion *task_done;
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int exit_code, time_remaining;
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try_catch->context = context;
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try_catch->try_result = 0;
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task_struct = kthread_create(kunit_generic_run_threadfn_adapter,
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try_catch, "kunit_try_catch_thread");
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if (IS_ERR(task_struct)) {
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try_catch->try_result = PTR_ERR(task_struct);
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try_catch->catch(try_catch->context);
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return;
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}
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get_task_struct(task_struct);
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/*
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* As for a vfork(2), task_struct->vfork_done (pointing to the
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* underlying kthread->exited) can be used to wait for the end of a
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* kernel thread. It is set to NULL when the thread exits, so we
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* keep a copy here.
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*/
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task_done = task_struct->vfork_done;
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wake_up_process(task_struct);
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time_remaining = wait_for_completion_timeout(task_done,
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kunit_test_timeout());
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if (time_remaining == 0) {
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try_catch->try_result = -ETIMEDOUT;
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kthread_stop(task_struct);
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}
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put_task_struct(task_struct);
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exit_code = try_catch->try_result;
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if (!exit_code)
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return;
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if (exit_code == -EFAULT)
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try_catch->try_result = 0;
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else if (exit_code == -EINTR) {
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if (test->last_seen.file)
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kunit_err(test, "try faulted: last line seen %s:%d\n",
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test->last_seen.file, test->last_seen.line);
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else
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kunit_err(test, "try faulted\n");
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} else if (exit_code == -ETIMEDOUT)
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kunit_err(test, "try timed out\n");
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else if (exit_code)
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kunit_err(test, "Unknown error: %d\n", exit_code);
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try_catch->catch(try_catch->context);
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}
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EXPORT_SYMBOL_GPL(kunit_try_catch_run);
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