The patch titled
Subject: kasan, fork: reset pointer tags of vmapped stacks
has been removed from the -mm tree. Its filename was
kasan-fork-reset-pointer-tags-of-vmapped-stacks.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Subject: kasan, fork: reset pointer tags of vmapped stacks
Once tag-based KASAN modes start tagging vmalloc() allocations, kernel
stacks start getting tagged if CONFIG_VMAP_STACK is enabled.
Reset the tag of kernel stack pointers after allocation in
alloc_thread_stack_node().
For SW_TAGS KASAN, when CONFIG_KASAN_STACK is enabled, the instrumentation
can't handle the SP register being tagged.
For HW_TAGS KASAN, there's no instrumentation-related issues. However,
the impact of having a tagged SP register needs to be properly evaluated,
so keep it non-tagged for now.
Note, that the memory for the stack allocation still gets tagged to catch
vmalloc-into-stack out-of-bounds accesses.
Link: https://lkml.kernel.org/r/c6c96f012371ecd80e1936509ebcd3b07a5956f7.1643047180.git.andreyknvl@xxxxxxxxxx
Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Reviewed-by: Alexander Potapenko <glider@xxxxxxxxxx>
Acked-by: Marco Elver <elver@xxxxxxxxxx>
Cc: Andrey Ryabinin <ryabinin.a.a@xxxxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Cc: Evgenii Stepanov <eugenis@xxxxxxxxxx>
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Cc: Peter Collingbourne <pcc@xxxxxxxxxx>
Cc: Vincenzo Frascino <vincenzo.frascino@xxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/fork.c | 2 ++
1 file changed, 2 insertions(+)
--- a/kernel/fork.c~kasan-fork-reset-pointer-tags-of-vmapped-stacks
+++ a/kernel/fork.c
@@ -326,6 +326,8 @@ static int alloc_thread_stack_node(struc
* so cache the vm_struct.
*/
tsk->stack_vm_area = vm;
+ if (stack)
+ stack = kasan_reset_tag(stack);
tsk->stack = stack;
return 0;
}
_
Patches currently in -mm which might be from andreyknvl@xxxxxxxxxx are
stacktrace-add-interface-based-on-shadow-call-stack.patch
arm64-scs-save-scs_sp-values-per-cpu-when-switching-stacks.patch
arm64-implement-stack_trace_save_shadow.patch
kasan-use-stack_trace_save_shadow.patch
