Re: [PATCH v3 5/6] kunit: add ability to run tests after boot using debugfs

On Tue, 5 Dec 2023 at 06:19, Rae Moar rmoar@google.com wrote:

Add functionality to run built-in tests after boot by writing to a debugfs file.

Add a new debugfs file labeled "run" for each test suite to use for this purpose.

As an example, write to the file using the following:

echo "any string" > /sys/kernel/debugfs/kunit/<testsuite>/run

This will trigger the test suite to run and will print results to the kernel log.

To guard against running tests concurrently with this feature, add a mutex lock around running kunit. This supports the current practice of not allowing tests to be run concurrently on the same kernel.

This new functionality could be used to design a parameter injection feature in the future.

Signed-off-by: Rae Moar rmoar@google.com

This looks good to me.

A future feature which may be useful would be to support other kunit actions here (like list, list_attr), but that's probably worth leaving as a follow-up.

Reviewed-by: David Gow davidgow@google.com

Cheers, -- David

Changes since v2:

• Move resetting the log to test.c
• Add is_init attribute and patches to change linker sections to avoid re-running tests that use init data and functions

lib/kunit/debugfs.c | 68 +++++++++++++++++++++++++++++++++++++++++++++ lib/kunit/test.c | 10 +++++++ 2 files changed, 78 insertions(+)

diff --git a/lib/kunit/debugfs.c b/lib/kunit/debugfs.c index 270d185737e6..2e0a92a0c461 100644 --- a/lib/kunit/debugfs.c +++ b/lib/kunit/debugfs.c @@ -8,12 +8,14 @@ #include <linux/module.h>

#include <kunit/test.h> +#include <kunit/test-bug.h>

#include "string-stream.h" #include "debugfs.h"

#define KUNIT_DEBUGFS_ROOT "kunit" #define KUNIT_DEBUGFS_RESULTS "results" +#define KUNIT_DEBUGFS_RUN "run"

/*

• Create a debugfs representation of test suites:

@@ -21,6 +23,8 @@

• Path Semantics
• /sys/kernel/debug/kunit/<testsuite>/results Show results of last run for

•                                         testsuite
  

• • /sys/kernel/debug/kunit/<testsuite>/run Write to this file to trigger

• •                                         testsuite to run
    
  */

@@ -99,6 +103,51 @@ static int debugfs_results_open(struct inode *inode, struct file *file) return single_open(file, debugfs_print_results, suite); }

+/*

• • Print a usage message to the debugfs "run" file
• • (/sys/kernel/debug/kunit/<testsuite>/run) if opened.
• */

+static int debugfs_print_run(struct seq_file *seq, void *v) +{

•   struct kunit_suite *suite = (struct kunit_suite *)seq->private;
  

•   seq_puts(seq, "Write to this file to trigger the test suite to run.\n");
  

•   seq_printf(seq, "usage: echo \"any string\" > /sys/kernel/debugfs/kunit/%s/run\n",
  

•                   suite->name);
  

•   return 0;
  

+}

+/*

• • The debugfs "run" file (/sys/kernel/debug/kunit/<testsuite>/run)
• • contains no information. Write to the file to trigger the test suite
• • to run.
• */

+static int debugfs_run_open(struct inode *inode, struct file *file) +{

•   struct kunit_suite *suite;
  

•   suite = (struct kunit_suite *)inode->i_private;
  

•   return single_open(file, debugfs_print_run, suite);
  

+}

+/*

• • Trigger a test suite to run by writing to the suite's "run" debugfs
• • file found at: /sys/kernel/debug/kunit/<testsuite>/run
• • Note: what is written to this file will not be saved.
• */

+static ssize_t debugfs_run(struct file *file,

•           const char __user *buf, size_t count, loff_t *ppos)
  

+{

•   struct inode *f_inode = file->f_inode;
  

•   struct kunit_suite *suite = (struct kunit_suite *) f_inode->i_private;
  

•   __kunit_test_suites_init(&suite, 1);
  

•   return count;
  

+}

static const struct file_operations debugfs_results_fops = { .open = debugfs_results_open, .read = seq_read, @@ -106,10 +155,22 @@ static const struct file_operations debugfs_results_fops = { .release = debugfs_release, };

+static const struct file_operations debugfs_run_fops = {

•   .open = debugfs_run_open,
  

•   .read = seq_read,
  

•   .write = debugfs_run,
  

•   .llseek = seq_lseek,
  

•   .release = debugfs_release,
  

+};

void kunit_debugfs_create_suite(struct kunit_suite *suite) { struct kunit_case *test_case;

•   /* If suite log already allocated, do not create new debugfs files. */
  

•   if (suite->log)
  

•           return;
  

•   /* Allocate logs before creating debugfs representation. */
    suite->log = alloc_string_stream(GFP_KERNEL);
    string_stream_set_append_newlines(suite->log, true);
  

@@ -124,6 +185,13 @@ void kunit_debugfs_create_suite(struct kunit_suite *suite) debugfs_create_file(KUNIT_DEBUGFS_RESULTS, S_IFREG | 0444, suite->debugfs, suite, &debugfs_results_fops);

•   /* Do not create file to re-run test if test runs on init */
  

•   if (!suite->attr.is_init) {
  

•           debugfs_create_file(KUNIT_DEBUGFS_RUN, S_IFREG | 0644,
  

•                               suite->debugfs,
  

•                               suite, &debugfs_run_fops);
  

•   }
  

}

void kunit_debugfs_destroy_suite(struct kunit_suite *suite) diff --git a/lib/kunit/test.c b/lib/kunit/test.c index 8bae6e2bc6a0..58e46bb3b4c4 100644 --- a/lib/kunit/test.c +++ b/lib/kunit/test.c @@ -13,6 +13,7 @@ #include <linux/kernel.h> #include <linux/module.h> #include <linux/moduleparam.h> +#include <linux/mutex.h> #include <linux/panic.h> #include <linux/sched/debug.h> #include <linux/sched.h> @@ -22,6 +23,8 @@ #include "string-stream.h" #include "try-catch-impl.h"

+static DEFINE_MUTEX(kunit_run_lock);

/*

• Hook to fail the current test and print an error message to the log.

*/ @@ -654,6 +657,7 @@ static void kunit_init_suite(struct kunit_suite *suite) kunit_debugfs_create_suite(suite); suite->status_comment[0] = '\0'; suite->suite_init_err = 0;

•   string_stream_clear(suite->log);
  

}

bool kunit_enabled(void) @@ -670,6 +674,11 @@ int __kunit_test_suites_init(struct kunit_suite * const * const suites, int num_ return 0; }

•   /* Use mutex lock to guard against running tests concurrently. */
  

•   if (mutex_lock_interruptible(&kunit_run_lock)) {
  

•           pr_err("kunit: test interrupted\n");
  

•           return -EINTR;
  

•   }
    static_branch_inc(&kunit_running);
  
    for (i = 0; i < num_suites; i++) {
  

@@ -678,6 +687,7 @@ int __kunit_test_suites_init(struct kunit_suite * const * const suites, int num_ }

    static_branch_dec(&kunit_running);

•   mutex_unlock(&kunit_run_lock);
    return 0;
  

} EXPORT_SYMBOL_GPL(__kunit_test_suites_init); -- 2.43.0.rc2.451.g8631bc7472-goog