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| author | Andrey Konovalov <andreyknvl@google.com> | 2022-06-09 20:18:47 +0200 |
|---|---|---|
| committer | akpm <akpm@linux-foundation.org> | 2022-07-04 03:08:39 +0200 |
| commit | 6c2f761dad7851d8088b91063ccaea3c970efe78 (patch) | |
| tree | 31c0fc3824144a4bb907b88a8f3824e6d0f79b8c /mm/vmalloc.c | |
| parent | mm: introduce clear_highpage_kasan_tagged (diff) | |
| download | linux-6c2f761dad7851d8088b91063ccaea3c970efe78.tar.xz linux-6c2f761dad7851d8088b91063ccaea3c970efe78.zip | |
kasan: fix zeroing vmalloc memory with HW_TAGS
HW_TAGS KASAN skips zeroing page_alloc allocations backing vmalloc
mappings via __GFP_SKIP_ZERO. Instead, these pages are zeroed via
kasan_unpoison_vmalloc() by passing the KASAN_VMALLOC_INIT flag.
The problem is that __kasan_unpoison_vmalloc() does not zero pages when
either kasan_vmalloc_enabled() or is_vmalloc_or_module_addr() fail.
Thus:
1. Change __vmalloc_node_range() to only set KASAN_VMALLOC_INIT when
__GFP_SKIP_ZERO is set.
2. Change __kasan_unpoison_vmalloc() to always zero pages when the
KASAN_VMALLOC_INIT flag is set.
3. Add WARN_ON() asserts to check that KASAN_VMALLOC_INIT cannot be set
in other early return paths of __kasan_unpoison_vmalloc().
Also clean up the comment in __kasan_unpoison_vmalloc.
Link: https://lkml.kernel.org/r/4bc503537efdc539ffc3f461c1b70162eea31cf6.1654798516.git.andreyknvl@google.com
Fixes: 23689e91fb22 ("kasan, vmalloc: add vmalloc tagging for HW_TAGS")
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Cc: Marco Elver <elver@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to '')
| -rw-r--r-- | mm/vmalloc.c | 10 |
1 files changed, 5 insertions, 5 deletions
diff --git a/mm/vmalloc.c b/mm/vmalloc.c index 5977b178694d..37939f96d2f4 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -3161,15 +3161,15 @@ again: /* * Mark the pages as accessible, now that they are mapped. - * The init condition should match the one in post_alloc_hook() - * (except for the should_skip_init() check) to make sure that memory - * is initialized under the same conditions regardless of the enabled - * KASAN mode. + * The condition for setting KASAN_VMALLOC_INIT should complement the + * one in post_alloc_hook() with regards to the __GFP_SKIP_ZERO check + * to make sure that memory is initialized under the same conditions. * Tag-based KASAN modes only assign tags to normal non-executable * allocations, see __kasan_unpoison_vmalloc(). */ kasan_flags |= KASAN_VMALLOC_VM_ALLOC; - if (!want_init_on_free() && want_init_on_alloc(gfp_mask)) + if (!want_init_on_free() && want_init_on_alloc(gfp_mask) && + (gfp_mask & __GFP_SKIP_ZERO)) kasan_flags |= KASAN_VMALLOC_INIT; /* KASAN_VMALLOC_PROT_NORMAL already set if required. */ area->addr = kasan_unpoison_vmalloc(area->addr, real_size, kasan_flags); |