kasan: remove vmalloc_percpu test

Commit 1a2473f0cbc0 ("kasan: improve vmalloc tests") added the
vmalloc_percpu KASAN test with the assumption that __alloc_percpu always
uses vmalloc internally, which is tagged by KASAN.

However, __alloc_percpu might allocate memory from the first per-CPU
chunk, which is not allocated via vmalloc().  As a result, the test might
fail.

Remove the test until proper KASAN annotation for the per-CPU allocated
are added; tracked in https://bugzilla.kernel.org/show_bug.cgi?id=215019.

Link: https://lkml.kernel.org/r/20241022160706.38943-1-andrey.konovalov@linux.dev
Fixes: 1a2473f0cbc0 ("kasan: improve vmalloc tests")
Signed-off-by: Andrey Konovalov <andreyknvl@gmail.com>
Reported-by: Samuel Holland <samuel.holland@sifive.com>
Link: https://lore.kernel.org/all/4a245fff-cc46-44d1-a5f9-fd2f1c3764ae@sifive.com/
Reported-by: Sabyrzhan Tasbolatov <snovitoll@gmail.com>
Link: https://lore.kernel.org/all/CACzwLxiWzNqPBp4C1VkaXZ2wDwvY3yZeetCi1TLGFipKW77drA@mail.gmail.com/
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Marco Elver <elver@google.com>
Cc: Sabyrzhan Tasbolatov <snovitoll@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/kasan/kasan_test_c.c b/mm/kasan/kasan_test_c.c
index a181e4780d9d35554c40a92089c7fa6a03d25f97..d8fb281e439d56a58d4934d43f7166ecec69cb06 100644 (file)
--- a/mm/kasan/kasan_test_c.c
+++ b/mm/kasan/kasan_test_c.c
@@ -1810,32 +1810,6 @@ static void vm_map_ram_tags(struct kunit *test)
        free_pages((unsigned long)p_ptr, 1);
 }
 
-static void vmalloc_percpu(struct kunit *test)
-{
-       char __percpu *ptr;
-       int cpu;
-
-       /*
-        * This test is specifically crafted for the software tag-based mode,
-        * the only tag-based mode that poisons percpu mappings.
-        */
-       KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_KASAN_SW_TAGS);
-
-       ptr = __alloc_percpu(PAGE_SIZE, PAGE_SIZE);
-
-       for_each_possible_cpu(cpu) {
-               char *c_ptr = per_cpu_ptr(ptr, cpu);
-
-               KUNIT_EXPECT_GE(test, (u8)get_tag(c_ptr), (u8)KASAN_TAG_MIN);
-               KUNIT_EXPECT_LT(test, (u8)get_tag(c_ptr), (u8)KASAN_TAG_KERNEL);
-
-               /* Make sure that in-bounds accesses don't crash the kernel. */
-               *c_ptr = 0;
-       }
-
-       free_percpu(ptr);
-}
-
 /*
  * Check that the assigned pointer tag falls within the [KASAN_TAG_MIN,
  * KASAN_TAG_KERNEL) range (note: excluding the match-all tag) for tag-based
@@ -2023,7 +1997,6 @@ static struct kunit_case kasan_kunit_test_cases[] = {
        KUNIT_CASE(vmalloc_oob),
        KUNIT_CASE(vmap_tags),
        KUNIT_CASE(vm_map_ram_tags),
-       KUNIT_CASE(vmalloc_percpu),
        KUNIT_CASE(match_all_not_assigned),
        KUNIT_CASE(match_all_ptr_tag),
        KUNIT_CASE(match_all_mem_tag),