diff options
| author | Andrey Konovalov <andreyknvl@google.com> | 2021-02-25 17:20:38 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2021-02-26 09:41:03 -0800 |
| commit | 7169487bc2a7c5732a6eeebc6dc3d1351d4a6350 (patch) | |
| tree | 2b762eb2a1e2173967fc1db818522d0bd4873c8f | |
| parent | c80a03664e154b7263af1c4dd53f42221d0c8283 (diff) | |
kasan: clarify that only first bug is reported in HW_TAGS
Hwardware tag-based KASAN only reports the first found bug. After that MTE
tag checking gets disabled. Clarify this in comments and documentation.
Link: https://lkml.kernel.org/r/00383ba88a47c3f8342d12263c24bdf95527b07d.1612546384.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 <aryabinin@virtuozzo.com>
Cc: Branislav Rankov <Branislav.Rankov@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Peter Collingbourne <pcc@google.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | Documentation/dev-tools/kasan.rst | 8 | ||||
| -rw-r--r-- | mm/kasan/hw_tags.c | 2 |
2 files changed, 7 insertions, 3 deletions
diff --git a/Documentation/dev-tools/kasan.rst b/Documentation/dev-tools/kasan.rst index cde14aeefca7..ddf4239a5890 100644 --- a/Documentation/dev-tools/kasan.rst +++ b/Documentation/dev-tools/kasan.rst @@ -155,7 +155,7 @@ Boot parameters ~~~~~~~~~~~~~~~ Hardware tag-based KASAN mode (see the section about various modes below) is -intended for use in production as a security mitigation. Therefore it supports +intended for use in production as a security mitigation. Therefore, it supports boot parameters that allow to disable KASAN competely or otherwise control particular KASAN features. @@ -165,7 +165,8 @@ particular KASAN features. traces collection (default: ``on``). - ``kasan.fault=report`` or ``=panic`` controls whether to only print a KASAN - report or also panic the kernel (default: ``report``). + report or also panic the kernel (default: ``report``). Note, that tag + checking gets disabled after the first reported bug. For developers ~~~~~~~~~~~~~~ @@ -295,6 +296,9 @@ Note, that enabling CONFIG_KASAN_HW_TAGS always results in in-kernel TBI being enabled. Even when kasan.mode=off is provided, or when the hardware doesn't support MTE (but supports TBI). +Hardware tag-based KASAN only reports the first found bug. After that MTE tag +checking gets disabled. + What memory accesses are sanitised by KASAN? -------------------------------------------- diff --git a/mm/kasan/hw_tags.c b/mm/kasan/hw_tags.c index b31aeef505dd..2aad21fda156 100644 --- a/mm/kasan/hw_tags.c +++ b/mm/kasan/hw_tags.c @@ -48,7 +48,7 @@ EXPORT_SYMBOL(kasan_flag_enabled); /* Whether to collect alloc/free stack traces. */ DEFINE_STATIC_KEY_FALSE(kasan_flag_stacktrace); -/* Whether panic or disable tag checking on fault. */ +/* Whether to panic or print a report and disable tag checking on fault. */ bool kasan_flag_panic __ro_after_init; /* kasan=off/on */ |