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kasan: switch kunit tests to console tracepoints

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Switch KUnit-compatible KASAN tests from using per-task KUnit resources to
console tracepoints.

This allows for two things:

1. Migrating tests that trigger a KASAN report in the context of a task
   other than current to KUnit framework.
   This is implemented in the patches that follow.

2. Parsing and matching the contents of KASAN reports.
   This is not yet implemented.

Link: https://lkml.kernel.org/r/9345acdd11e953b207b0ed4724ff780e63afeb36.1664298455.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Marco Elver <elver@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Andrey Konovalov 2022-09-27 19:09:09 +02:00 committed by Andrew Morton
parent a5454f9524
commit 7ce0ea19d5
4 changed files with 63 additions and 63 deletions
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2
lib/Kconfig.kasan
View File

@ -181,7 +181,7 @@ config KASAN_VMALLOC
config KASAN_KUNIT_TEST
tristate "KUnit-compatible tests of KASAN bug detection capabilities" if !KUNIT_ALL_TESTS
depends on KASAN && KUNIT
depends on KASAN && KUNIT && TRACEPOINTS
default KUNIT_ALL_TESTS
help
A KUnit-based KASAN test suite. Triggers different kinds of

8
mm/kasan/kasan.h
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@ -261,14 +261,6 @@ struct kasan_stack_ring {
#endif /* CONFIG_KASAN_SW_TAGS || CONFIG_KASAN_HW_TAGS */
#if IS_ENABLED(CONFIG_KASAN_KUNIT_TEST)
/* Used in KUnit-compatible KASAN tests. */
struct kunit_kasan_status {
bool report_found;
bool sync_fault;
};
#endif
#if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)
static inline const void *kasan_shadow_to_mem(const void *shadow_addr)

85
mm/kasan/kasan_test.c
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@ -5,8 +5,12 @@
* Author: Andrey Ryabinin <a.ryabinin@samsung.com>
*/
#define pr_fmt(fmt) "kasan_test: " fmt
#include <kunit/test.h>
#include <linux/bitops.h>
#include <linux/delay.h>
#include <linux/io.h>
#include <linux/kasan.h>
#include <linux/kernel.h>
#include <linux/mm.h>
@ -14,21 +18,28 @@
#include <linux/module.h>
#include <linux/printk.h>
#include <linux/random.h>
#include <linux/set_memory.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/tracepoint.h>
#include <linux/uaccess.h>
#include <linux/io.h>
#include <linux/vmalloc.h>
#include <linux/set_memory.h>
#include <trace/events/printk.h>
#include <asm/page.h>
#include <kunit/test.h>
#include "kasan.h"
#define OOB_TAG_OFF (IS_ENABLED(CONFIG_KASAN_GENERIC) ? 0 : KASAN_GRANULE_SIZE)
static bool multishot;
/* Fields set based on lines observed in the console. */
static struct {
bool report_found;
bool async_fault;
} test_status;
/*
* Some tests use these global variables to store return values from function
* calls that could otherwise be eliminated by the compiler as dead code.
@ -36,35 +47,61 @@
void *kasan_ptr_result;
int kasan_int_result;
static struct kunit_resource resource;
static struct kunit_kasan_status test_status;
static bool multishot;
/* Probe for console output: obtains test_status lines of interest. */
static void probe_console(void *ignore, const char *buf, size_t len)
{
if (strnstr(buf, "BUG: KASAN: ", len))
WRITE_ONCE(test_status.report_found, true);
else if (strnstr(buf, "Asynchronous fault: ", len))
WRITE_ONCE(test_status.async_fault, true);
}
/*
* Temporarily enable multi-shot mode. Otherwise, KASAN would only report the
* first detected bug and panic the kernel if panic_on_warn is enabled. For
* hardware tag-based KASAN also allow tag checking to be reenabled for each
* test, see the comment for KUNIT_EXPECT_KASAN_FAIL().
*/
static int kasan_test_init(struct kunit *test)
static void register_tracepoints(struct tracepoint *tp, void *ignore)
{
check_trace_callback_type_console(probe_console);
if (!strcmp(tp->name, "console"))
WARN_ON(tracepoint_probe_register(tp, probe_console, NULL));
}
static void unregister_tracepoints(struct tracepoint *tp, void *ignore)
{
if (!strcmp(tp->name, "console"))
tracepoint_probe_unregister(tp, probe_console, NULL);
}
static int kasan_suite_init(struct kunit_suite *suite)
{
if (!kasan_enabled()) {
kunit_err(test, "can't run KASAN tests with KASAN disabled");
pr_err("Can't run KASAN tests with KASAN disabled");
return -1;
}
/*
* Temporarily enable multi-shot mode. Otherwise, KASAN would only
* report the first detected bug and panic the kernel if panic_on_warn
* is enabled.
*/
multishot = kasan_save_enable_multi_shot();
test_status.report_found = false;
test_status.sync_fault = false;
kunit_add_named_resource(test, NULL, NULL, &resource,
"kasan_status", &test_status);
/*
* Because we want to be able to build the test as a module, we need to
* iterate through all known tracepoints, since the static registration
* won't work here.
*/
for_each_kernel_tracepoint(register_tracepoints, NULL);
return 0;
}
static void kasan_suite_exit(struct kunit_suite *suite)
{
kasan_restore_multi_shot(multishot);
for_each_kernel_tracepoint(unregister_tracepoints, NULL);
tracepoint_synchronize_unregister();
}
static void kasan_test_exit(struct kunit *test)
{
kasan_restore_multi_shot(multishot);
KUNIT_EXPECT_FALSE(test, test_status.report_found);
KUNIT_EXPECT_FALSE(test, READ_ONCE(test_status.report_found));
}
/**
@ -106,11 +143,12 @@ static void kasan_test_exit(struct kunit *test)
if (IS_ENABLED(CONFIG_KASAN_HW_TAGS) && \
kasan_sync_fault_possible()) { \
if (READ_ONCE(test_status.report_found) && \
READ_ONCE(test_status.sync_fault)) \
!READ_ONCE(test_status.async_fault)) \
kasan_enable_tagging(); \
migrate_enable(); \
} \
WRITE_ONCE(test_status.report_found, false); \
WRITE_ONCE(test_status.async_fault, false); \
} while (0)
#define KASAN_TEST_NEEDS_CONFIG_ON(test, config) do { \
@ -1447,9 +1485,10 @@ static struct kunit_case kasan_kunit_test_cases[] = {
static struct kunit_suite kasan_kunit_test_suite = {
.name = "kasan",
.init = kasan_test_init,
.test_cases = kasan_kunit_test_cases,
.exit = kasan_test_exit,
.suite_init = kasan_suite_init,
.suite_exit = kasan_suite_exit,
};
kunit_test_suite(kasan_kunit_test_suite);

31
mm/kasan/report.c
View File

@ -30,8 +30,6 @@
#include <asm/sections.h>
#include <kunit/test.h>
#include "kasan.h"
#include "../slab.h"
@ -114,41 +112,12 @@ EXPORT_SYMBOL_GPL(kasan_restore_multi_shot);
#endif
#if IS_ENABLED(CONFIG_KASAN_KUNIT_TEST)
static void update_kunit_status(bool sync)
{
struct kunit *test;
struct kunit_resource *resource;
struct kunit_kasan_status *status;
test = current->kunit_test;
if (!test)
return;
resource = kunit_find_named_resource(test, "kasan_status");
if (!resource) {
kunit_set_failure(test);
return;
}
status = (struct kunit_kasan_status *)resource->data;
WRITE_ONCE(status->report_found, true);
WRITE_ONCE(status->sync_fault, sync);
kunit_put_resource(resource);
}
#else
static void update_kunit_status(bool sync) { }
#endif
static DEFINE_SPINLOCK(report_lock);
static void start_report(unsigned long *flags, bool sync)
{
/* Respect the /proc/sys/kernel/traceoff_on_warning interface. */
disable_trace_on_warning();
/* Update status of the currently running KASAN test. */
update_kunit_status(sync);
/* Do not allow LOCKDEP mangling KASAN reports. */
lockdep_off();
/* Make sure we don't end up in loop. */