kasan: clean up kasan_requires_meta

Currently, for Generic KASAN mode, kasan_requires_meta is defined to
return kasan_stack_collection_enabled.

Even though the Generic mode does not support disabling stack trace
collection, kasan_requires_meta was implemented in this way to make it
easier to implement the disabling for the Generic mode in the future.

However, for the Generic mode, the per-object metadata also stores the
quarantine link.  So even if disabling stack collection is implemented,
the per-object metadata will still be required.

Fix kasan_requires_meta to return true for the Generic mode and update the
related comments.

This change does not fix any observable bugs but rather just brings the
code to a cleaner state.

Link: https://lkml.kernel.org/r/8086623407095ac1c82377a2107dcc5845f99cfa.1703188911.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Marco Elver <elver@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Andrey Konovalov 2023-12-21 21:04:46 +01:00 committed by Andrew Morton
parent c20e3feadd
commit 3067b919ed

View File

@ -101,21 +101,21 @@ static inline bool kasan_sample_page_alloc(unsigned int order)
#ifdef CONFIG_KASAN_GENERIC
/* Generic KASAN uses per-object metadata to store stack traces. */
/*
* Generic KASAN uses per-object metadata to store alloc and free stack traces
* and the quarantine link.
*/
static inline bool kasan_requires_meta(void)
{
/*
* Technically, Generic KASAN always collects stack traces right now.
* However, let's use kasan_stack_collection_enabled() in case the
* kasan.stacktrace command-line argument is changed to affect
* Generic KASAN.
*/
return kasan_stack_collection_enabled();
return true;
}
#else /* CONFIG_KASAN_GENERIC */
/* Tag-based KASAN modes do not use per-object metadata. */
/*
* Tag-based KASAN modes do not use per-object metadata: they use the stack
* ring to store alloc and free stack traces and do not use qurantine.
*/
static inline bool kasan_requires_meta(void)
{
return false;