+ kasan-fork-reset-pointer-tags-of-vmapped-stacks-fix.patch added to -mm tree

+ kasan-fork-reset-pointer-tags-of-vmapped-stacks-fix.patch added to -mm tree

[Andrew Morton]

The patch titled
     Subject: fix for "kasan, fork: reset pointer tags of vmapped stacks"
has been added to the -mm tree.  Its filename is
     kasan-fork-reset-pointer-tags-of-vmapped-stacks-fix.patch

This patch should soon appear at
    https://ozlabs.org/~akpm/mmots/broken-out/kasan-fork-reset-pointer-tags-of-vmapped-stacks-fix.patch
and later at
    https://ozlabs.org/~akpm/mmotm/broken-out/kasan-fork-reset-pointer-tags-of-vmapped-stacks-fix.patch

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------------------------------------------------------
From: Andrey Konovalov <andreyknvl@google.com>
Subject: fix for "kasan, fork: reset pointer tags of vmapped stacks"

That patch didn't update the case when a stack is retrived from
cached_stacks in alloc_thread_stack_node().  As cached_stacks stores
vm_structs and not stack pointers themselves, the pointer tag needs to be
reset there as well.

Link: https://lkml.kernel.org/r/f50c5f96ef896d7936192c888b0c0a7674e33184.1644943792.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Marco Elver <elver@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Collingbourne <pcc@google.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 kernel/fork.c |   10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

--- a/kernel/fork.c~kasan-fork-reset-pointer-tags-of-vmapped-stacks-fix
+++ a/kernel/fork.c
@@ -226,15 +226,17 @@ static unsigned long *alloc_thread_stack
 		if (!s)
 			continue;
 
-		/* Mark stack accessible for KASAN. */
+		/* Reset stack metadata. */
 		kasan_unpoison_range(s->addr, THREAD_SIZE);
 
+		stack = kasan_reset_tag(s->addr);
+
 		/* Clear stale pointers from reused stack. */
-		memset(s->addr, 0, THREAD_SIZE);
+		memset(stack, 0, THREAD_SIZE);
 
 		tsk->stack_vm_area = s;
-		tsk->stack = s->addr;
-		return s->addr;
+		tsk->stack = stack;
+		return stack;
 	}
 
 	/*
_

Patches currently in -mm which might be from andreyknvl@google.com are

kasan-test-prevent-cache-merging-in-kmem_cache_double_destroy.patch
kasan-page_alloc-deduplicate-should_skip_kasan_poison.patch
kasan-page_alloc-move-tag_clear_highpage-out-of-kernel_init_free_pages.patch
kasan-page_alloc-merge-kasan_free_pages-into-free_pages_prepare.patch
kasan-page_alloc-simplify-kasan_poison_pages-call-site.patch
kasan-page_alloc-init-memory-of-skipped-pages-on-free.patch
kasan-drop-skip_kasan_poison-variable-in-free_pages_prepare.patch
mm-clarify-__gfp_zerotags-comment.patch
kasan-only-apply-__gfp_zerotags-when-memory-is-zeroed.patch
kasan-page_alloc-refactor-init-checks-in-post_alloc_hook.patch
kasan-page_alloc-merge-kasan_alloc_pages-into-post_alloc_hook.patch
kasan-page_alloc-combine-tag_clear_highpage-calls-in-post_alloc_hook.patch
kasan-page_alloc-move-setpageskipkasanpoison-in-post_alloc_hook.patch
kasan-page_alloc-move-kernel_init_free_pages-in-post_alloc_hook.patch
kasan-page_alloc-rework-kasan_unpoison_pages-call-site.patch
kasan-clean-up-metadata-byte-definitions.patch
kasan-define-kasan_vmalloc_invalid-for-sw_tags.patch
kasan-x86-arm64-s390-rename-functions-for-modules-shadow.patch
kasan-vmalloc-drop-outdated-vm_kasan-comment.patch
kasan-reorder-vmalloc-hooks.patch
kasan-add-wrappers-for-vmalloc-hooks.patch
kasan-vmalloc-reset-tags-in-vmalloc-functions.patch
kasan-fork-reset-pointer-tags-of-vmapped-stacks.patch
kasan-arm64-reset-pointer-tags-of-vmapped-stacks.patch
kasan-fork-reset-pointer-tags-of-vmapped-stacks-fix.patch
kasan-vmalloc-add-vmalloc-tagging-for-sw_tags.patch
kasan-vmalloc-arm64-mark-vmalloc-mappings-as-pgprot_tagged.patch
kasan-vmalloc-unpoison-vm_alloc-pages-after-mapping.patch
kasan-mm-only-define-___gfp_skip_kasan_poison-with-hw_tags.patch
kasan-page_alloc-allow-skipping-unpoisoning-for-hw_tags.patch
kasan-page_alloc-allow-skipping-memory-init-for-hw_tags.patch
kasan-vmalloc-add-vmalloc-tagging-for-hw_tags.patch
kasan-vmalloc-only-tag-normal-vmalloc-allocations.patch
kasan-arm64-dont-tag-executable-vmalloc-allocations.patch
kasan-mark-kasan_arg_stacktrace-as-__initdata.patch
kasan-clean-up-feature-flags-for-hw_tags-mode.patch
kasan-add-kasanvmalloc-command-line-flag.patch
kasan-allow-enabling-kasan_vmalloc-and-sw-hw_tags.patch
arm64-select-kasan_vmalloc-for-sw-hw_tags-modes.patch
kasan-documentation-updates.patch
kasan-improve-vmalloc-tests.patch
kasan-improve-vmalloc-tests-fix-2.patch
kasan-test-support-async-again-and-asymm-modes-for-hw_tags.patch