From ec3e837d8fd96c68599b2861dd412094b7bc335c Mon Sep 17 00:00:00 2001 From: Ilya Leoshkevich Date: Fri, 21 Jun 2024 13:34:55 +0200 Subject: kmsan: allow disabling KMSAN checks for the current task Like for KASAN, it's useful to temporarily disable KMSAN checks around, e.g., redzone accesses. Introduce kmsan_disable_current() and kmsan_enable_current(), which are similar to their KASAN counterparts. Make them reentrant in order to handle memory allocations in interrupt context. Repurpose the allow_reporting field for this. Link: https://lkml.kernel.org/r/20240621113706.315500-12-iii@linux.ibm.com Signed-off-by: Ilya Leoshkevich Reviewed-by: Alexander Potapenko Cc: Alexander Gordeev Cc: Christian Borntraeger Cc: Christoph Lameter Cc: David Rientjes Cc: Dmitry Vyukov Cc: Heiko Carstens Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com> Cc: Joonsoo Kim Cc: Cc: Marco Elver Cc: Mark Rutland Cc: Masami Hiramatsu (Google) Cc: Pekka Enberg Cc: Roman Gushchin Cc: Steven Rostedt (Google) Cc: Sven Schnelle Cc: Vasily Gorbik Cc: Vlastimil Babka Signed-off-by: Andrew Morton --- Documentation/dev-tools/kmsan.rst | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) (limited to 'Documentation') diff --git a/Documentation/dev-tools/kmsan.rst b/Documentation/dev-tools/kmsan.rst index 323eedad53cd..6a48d96c5c85 100644 --- a/Documentation/dev-tools/kmsan.rst +++ b/Documentation/dev-tools/kmsan.rst @@ -110,6 +110,13 @@ in the Makefile. Think of this as applying ``__no_sanitize_memory`` to every function in the file or directory. Most users won't need KMSAN_SANITIZE, unless their code gets broken by KMSAN (e.g. runs at early boot time). +KMSAN checks can also be temporarily disabled for the current task using +``kmsan_disable_current()`` and ``kmsan_enable_current()`` calls. Each +``kmsan_enable_current()`` call must be preceded by a +``kmsan_disable_current()`` call; these call pairs may be nested. One needs to +be careful with these calls, keeping the regions short and preferring other +ways to disable instrumentation, where possible. + Support ======= @@ -338,11 +345,11 @@ Per-task KMSAN state ~~~~~~~~~~~~~~~~~~~~ Every task_struct has an associated KMSAN task state that holds the KMSAN -context (see above) and a per-task flag disallowing KMSAN reports:: +context (see above) and a per-task counter disallowing KMSAN reports:: struct kmsan_context { ... - bool allow_reporting; + unsigned int depth; struct kmsan_context_state cstate; ... } -- cgit v1.2.3