The patch titled
Subject: kasan, arm64: allow using KUnit tests with HW_TAGS mode
has been added to the -mm tree. Its filename is
kasan-arm64-allow-using-kunit-tests-with-hw_tags-mode.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/kasan-arm64-allow-using-kunit-tests-with-hw_tags-mode.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/kasan-arm64-allow-using-kunit-tests-with-hw_tags-mode.patch
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------------------------------------------------------
From: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Subject: kasan, arm64: allow using KUnit tests with HW_TAGS mode
On a high level, this patch allows running KUnit KASAN tests with the
hardware tag-based KASAN mode.
Internally, this change reenables tag checking at the end of each KASAN
test that triggers a tag fault and leads to tag checking being disabled.
Also simplify is_write calculation in report_tag_fault.
With this patch KASAN tests are still failing for the hardware tag-based
mode; fixes come in the next few patches.
Link: https://linux-review.googlesource.com/id/Id94dc9eccd33b23cda4950be408c27f879e474c8
Link: https://lkml.kernel.org/r/51b23112cf3fd62b8f8e9df81026fa2b15870501.1610733117.git.andreyknvl@xxxxxxxxxx
Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Reviewed-by: Catalin Marinas <catalin.marinas@xxxxxxx>
Reviewed-by: Vincenzo Frascino <vincenzo.frascino@xxxxxxx>
Cc: Alexander Potapenko <glider@xxxxxxxxxx>
Cc: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx>
Cc: Branislav Rankov <Branislav.Rankov@xxxxxxx>
Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Cc: Evgenii Stepanov <eugenis@xxxxxxxxxx>
Cc: Kevin Brodsky <kevin.brodsky@xxxxxxx>
Cc: Marco Elver <elver@xxxxxxxxxx>
Cc: Peter Collingbourne <pcc@xxxxxxxxxx>
Cc: Will Deacon <will.deacon@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/arm64/include/asm/memory.h | 1
arch/arm64/include/asm/mte-kasan.h | 12 +++++++
arch/arm64/kernel/mte.c | 12 +++++++
arch/arm64/mm/fault.c | 20 +++++++++---
lib/Kconfig.kasan | 4 +-
lib/test_kasan.c | 42 ++++++++++++++++++---------
mm/kasan/kasan.h | 9 +++++
7 files changed, 79 insertions(+), 21 deletions(-)
--- a/arch/arm64/include/asm/memory.h~kasan-arm64-allow-using-kunit-tests-with-hw_tags-mode
+++ a/arch/arm64/include/asm/memory.h
@@ -232,6 +232,7 @@ static inline const void *__tag_set(cons
#ifdef CONFIG_KASAN_HW_TAGS
#define arch_enable_tagging() mte_enable_kernel()
+#define arch_set_tagging_report_once(state) mte_set_report_once(state)
#define arch_init_tags(max_tag) mte_init_tags(max_tag)
#define arch_get_random_tag() mte_get_random_tag()
#define arch_get_mem_tag(addr) mte_get_mem_tag(addr)
--- a/arch/arm64/include/asm/mte-kasan.h~kasan-arm64-allow-using-kunit-tests-with-hw_tags-mode
+++ a/arch/arm64/include/asm/mte-kasan.h
@@ -32,6 +32,9 @@ void *mte_set_mem_tag_range(void *addr,
void mte_enable_kernel(void);
void mte_init_tags(u64 max_tag);
+void mte_set_report_once(bool state);
+bool mte_report_once(void);
+
#else /* CONFIG_ARM64_MTE */
static inline u8 mte_get_ptr_tag(void *ptr)
@@ -60,6 +63,15 @@ static inline void mte_init_tags(u64 max
{
}
+static inline void mte_set_report_once(bool state)
+{
+}
+
+static inline bool mte_report_once(void)
+{
+ return false;
+}
+
#endif /* CONFIG_ARM64_MTE */
#endif /* __ASSEMBLY__ */
--- a/arch/arm64/kernel/mte.c~kasan-arm64-allow-using-kunit-tests-with-hw_tags-mode
+++ a/arch/arm64/kernel/mte.c
@@ -25,6 +25,8 @@
u64 gcr_kernel_excl __ro_after_init;
+static bool report_fault_once = true;
+
static void mte_sync_page_tags(struct page *page, pte_t *ptep, bool check_swap)
{
pte_t old_pte = READ_ONCE(*ptep);
@@ -158,6 +160,16 @@ void mte_enable_kernel(void)
isb();
}
+void mte_set_report_once(bool state)
+{
+ WRITE_ONCE(report_fault_once, state);
+}
+
+bool mte_report_once(void)
+{
+ return READ_ONCE(report_fault_once);
+}
+
static void update_sctlr_el1_tcf0(u64 tcf0)
{
/* ISB required for the kernel uaccess routines */
--- a/arch/arm64/mm/fault.c~kasan-arm64-allow-using-kunit-tests-with-hw_tags-mode
+++ a/arch/arm64/mm/fault.c
@@ -302,12 +302,24 @@ static void die_kernel_fault(const char
static void report_tag_fault(unsigned long addr, unsigned int esr,
struct pt_regs *regs)
{
- bool is_write = ((esr & ESR_ELx_WNR) >> ESR_ELx_WNR_SHIFT) != 0;
+ static bool reported;
+ bool is_write;
+
+ if (READ_ONCE(reported))
+ return;
+
+ /*
+ * This is used for KASAN tests and assumes that no MTE faults
+ * happened before running the tests.
+ */
+ if (mte_report_once())
+ WRITE_ONCE(reported, true);
/*
* SAS bits aren't set for all faults reported in EL1, so we can't
* find out access size.
*/
+ is_write = !!(esr & ESR_ELx_WNR);
kasan_report(addr, 0, is_write, regs->pc);
}
#else
@@ -319,12 +331,8 @@ static inline void report_tag_fault(unsi
static void do_tag_recovery(unsigned long addr, unsigned int esr,
struct pt_regs *regs)
{
- static bool reported;
- if (!READ_ONCE(reported)) {
- report_tag_fault(addr, esr, regs);
- WRITE_ONCE(reported, true);
- }
+ report_tag_fault(addr, esr, regs);
/*
* Disable MTE Tag Checking on the local CPU for the current EL.
--- a/lib/Kconfig.kasan~kasan-arm64-allow-using-kunit-tests-with-hw_tags-mode
+++ a/lib/Kconfig.kasan
@@ -190,11 +190,11 @@ config KASAN_KUNIT_TEST
kernel debugging features like KASAN.
For more information on KUnit and unit tests in general, please refer
- to the KUnit documentation in Documentation/dev-tools/kunit
+ to the KUnit documentation in Documentation/dev-tools/kunit.
config TEST_KASAN_MODULE
tristate "KUnit-incompatible tests of KASAN bug detection capabilities"
- depends on m && KASAN
+ depends on m && KASAN && !KASAN_HW_TAGS
help
This is a part of the KASAN test suite that is incompatible with
KUnit. Currently includes tests that do bad copy_from/to_user
--- a/lib/test_kasan.c~kasan-arm64-allow-using-kunit-tests-with-hw_tags-mode
+++ a/lib/test_kasan.c
@@ -41,16 +41,20 @@ static bool multishot;
/*
* Temporarily enable multi-shot mode. Otherwise, KASAN would only report the
- * first detected bug and panic the kernel if panic_on_warn is enabled.
+ * 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)
{
multishot = kasan_save_enable_multi_shot();
+ hw_set_tagging_report_once(false);
return 0;
}
static void kasan_test_exit(struct kunit *test)
{
+ hw_set_tagging_report_once(true);
kasan_restore_multi_shot(multishot);
}
@@ -59,19 +63,31 @@ static void kasan_test_exit(struct kunit
* KASAN report; causes a test failure otherwise. This relies on a KUnit
* resource named "kasan_data". Do not use this name for KUnit resources
* outside of KASAN tests.
+ *
+ * For hardware tag-based KASAN, when a tag fault happens, tag checking is
+ * normally auto-disabled. When this happens, this test handler reenables
+ * tag checking. As tag checking can be only disabled or enabled per CPU, this
+ * handler disables migration (preemption).
*/
-#define KUNIT_EXPECT_KASAN_FAIL(test, expression) do { \
- fail_data.report_expected = true; \
- fail_data.report_found = false; \
- kunit_add_named_resource(test, \
- NULL, \
- NULL, \
- &resource, \
- "kasan_data", &fail_data); \
- expression; \
- KUNIT_EXPECT_EQ(test, \
- fail_data.report_expected, \
- fail_data.report_found); \
+#define KUNIT_EXPECT_KASAN_FAIL(test, expression) do { \
+ if (IS_ENABLED(CONFIG_KASAN_HW_TAGS)) \
+ migrate_disable(); \
+ fail_data.report_expected = true; \
+ fail_data.report_found = false; \
+ kunit_add_named_resource(test, \
+ NULL, \
+ NULL, \
+ &resource, \
+ "kasan_data", &fail_data); \
+ expression; \
+ KUNIT_EXPECT_EQ(test, \
+ fail_data.report_expected, \
+ fail_data.report_found); \
+ if (IS_ENABLED(CONFIG_KASAN_HW_TAGS)) { \
+ if (fail_data.report_found) \
+ hw_enable_tagging(); \
+ migrate_enable(); \
+ } \
} while (0)
#define KASAN_TEST_NEEDS_CONFIG_ON(test, config) do { \
--- a/mm/kasan/kasan.h~kasan-arm64-allow-using-kunit-tests-with-hw_tags-mode
+++ a/mm/kasan/kasan.h
@@ -280,6 +280,9 @@ static inline const void *arch_kasan_set
#ifndef arch_init_tags
#define arch_init_tags(max_tag)
#endif
+#ifndef arch_set_tagging_report_once
+#define arch_set_tagging_report_once(state)
+#endif
#ifndef arch_get_random_tag
#define arch_get_random_tag() (0xFF)
#endif
@@ -292,10 +295,16 @@ static inline const void *arch_kasan_set
#define hw_enable_tagging() arch_enable_tagging()
#define hw_init_tags(max_tag) arch_init_tags(max_tag)
+#define hw_set_tagging_report_once(state) arch_set_tagging_report_once(state)
#define hw_get_random_tag() arch_get_random_tag()
#define hw_get_mem_tag(addr) arch_get_mem_tag(addr)
#define hw_set_mem_tag_range(addr, size, tag) arch_set_mem_tag_range((addr), (size), (tag))
+#else /* CONFIG_KASAN_HW_TAGS */
+
+#define hw_enable_tagging()
+#define hw_set_tagging_report_once(state)
+
#endif /* CONFIG_KASAN_HW_TAGS */
#ifdef CONFIG_KASAN_SW_TAGS
_
Patches currently in -mm which might be from andreyknvl@xxxxxxxxxx are
kasan-fix-hw_tags-boot-parameters.patch
kasan-prefix-global-functions-with-kasan_.patch
kasan-clarify-hw_tags-impact-on-tbi.patch
kasan-clean-up-comments-in-tests.patch
kasan-add-macros-to-simplify-checking-test-constraints.patch
kasan-add-match-all-tag-tests.patch
kasan-arm64-allow-using-kunit-tests-with-hw_tags-mode.patch
kasan-rename-config_test_kasan_module.patch
kasan-add-compiler-barriers-to-kunit_expect_kasan_fail.patch
kasan-adapt-kmalloc_uaf2-test-to-hw_tags-mode.patch
kasan-fix-memory-corruption-in-kasan_bitops_tags-test.patch
kasan-move-_ret_ip_-to-inline-wrappers.patch
kasan-fix-bug-detection-via-ksize-for-hw_tags-mode.patch
kasan-add-proper-page-allocator-tests.patch
kasan-add-a-test-for-kmem_cache_alloc-free_bulk.patch
kasan-dont-run-tests-when-kasan-is-not-enabled.patch
