diff options
| author | Alexander Potapenko <glider@google.com> | 2026-02-13 10:54:10 +0100 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2026-02-24 11:13:25 -0800 |
| commit | 09833d99db36d74456a4d13eb29c32d56ff8f2b6 (patch) | |
| tree | 269802372892995151f6753a0a0061ac0a278a16 | |
| parent | 6de23f81a5e08be8fbf5e8d7e9febc72a5b5f27f (diff) | |
mm/kfence: disable KFENCE upon KASAN HW tags enablement
KFENCE does not currently support KASAN hardware tags. As a result, the
two features are incompatible when enabled simultaneously.
Given that MTE provides deterministic protection and KFENCE is a
sampling-based debugging tool, prioritize the stronger hardware
protections. Disable KFENCE initialization and free the pre-allocated
pool if KASAN hardware tags are detected to ensure the system maintains
the security guarantees provided by MTE.
Link: https://lkml.kernel.org/r/20260213095410.1862978-1-glider@google.com
Fixes: 0ce20dd84089 ("mm: add Kernel Electric-Fence infrastructure")
Signed-off-by: Alexander Potapenko <glider@google.com>
Suggested-by: Marco Elver <elver@google.com>
Reviewed-by: Marco Elver <elver@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Ernesto Martinez Garcia <ernesto.martinezgarcia@tugraz.at>
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: Kees Cook <kees@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
| -rw-r--r-- | mm/kfence/core.c | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/mm/kfence/core.c b/mm/kfence/core.c index b4ea3262c925..b5aedf505cec 100644 --- a/mm/kfence/core.c +++ b/mm/kfence/core.c @@ -13,6 +13,7 @@ #include <linux/hash.h> #include <linux/irq_work.h> #include <linux/jhash.h> +#include <linux/kasan-enabled.h> #include <linux/kcsan-checks.h> #include <linux/kfence.h> #include <linux/kmemleak.h> @@ -917,6 +918,20 @@ void __init kfence_alloc_pool_and_metadata(void) return; /* + * If KASAN hardware tags are enabled, disable KFENCE, because it + * does not support MTE yet. + */ + if (kasan_hw_tags_enabled()) { + pr_info("disabled as KASAN HW tags are enabled\n"); + if (__kfence_pool) { + memblock_free(__kfence_pool, KFENCE_POOL_SIZE); + __kfence_pool = NULL; + } + kfence_sample_interval = 0; + return; + } + + /* * If the pool has already been initialized by arch, there is no need to * re-allocate the memory pool. */ |