The patch titled
Subject: kasan: don't tag stacks allocated with pagealloc
has been added to the -mm tree. Its filename is
kasan-dont-tag-stacks-allocated-with-pagealloc.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/kasan-dont-tag-stacks-allocated-with-pagealloc.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/kasan-dont-tag-stacks-allocated-with-pagealloc.patch
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------------------------------------------------------
From: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Subject: kasan: don't tag stacks allocated with pagealloc
Patch series "kasan: support stack instrumentation for tag-based mode".
This patch (of 4):
Prepare Software Tag-Based KASAN for stack tagging support.
With Tag-Based KASAN when kernel stacks are allocated via pagealloc (which
happens when CONFIG_VMAP_STACK is not enabled), they get tagged. KASAN
instrumentation doesn't expect the sp register to be tagged, and this
leads to false-positive reports.
Fix by resetting the tag of kernel stack pointers after allocation.
Link: http://lkml.kernel.org/r/cover.1596199677.git.andreyknvl@xxxxxxxxxx
Link: http://lkml.kernel.org/r/01c678b877755bcf29009176592402cdf6f2cb15.1596199677.git.andreyknvl@xxxxxxxxxx
Link: https://bugzilla.kernel.org/show_bug.cgi?id=203497
Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Cc: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx>
Cc: Alexander Potapenko <glider@xxxxxxxxxx>
Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Cc: Marco Elver <elver@xxxxxxxxxx>
Cc: Walter Wu <walter-zh.wu@xxxxxxxxxxxx>
Cc: Elena Petrova <lenaptr@xxxxxxxxxx>
Cc: Vincenzo Frascino <vincenzo.frascino@xxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/fork.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
--- a/kernel/fork.c~kasan-dont-tag-stacks-allocated-with-pagealloc
+++ a/kernel/fork.c
@@ -261,7 +261,7 @@ static unsigned long *alloc_thread_stack
THREAD_SIZE_ORDER);
if (likely(page)) {
- tsk->stack = page_address(page);
+ tsk->stack = kasan_reset_tag(page_address(page));
return tsk->stack;
}
return NULL;
@@ -302,6 +302,7 @@ static unsigned long *alloc_thread_stack
{
unsigned long *stack;
stack = kmem_cache_alloc_node(thread_stack_cache, THREADINFO_GFP, node);
+ stack = kasan_reset_tag(stack);
tsk->stack = stack;
return stack;
}
_
Patches currently in -mm which might be from andreyknvl@xxxxxxxxxx are
kasan-dont-tag-stacks-allocated-with-pagealloc.patch
kasan-arm64-dont-instrument-functions-that-enable-kasan.patch
kasan-allow-enabling-stack-tagging-for-tag-based-mode.patch
kasan-adjust-kasan_stack_oob-for-tag-based-mode.patch
