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mm/memblock.c: skip kmemleak for kasan_init()

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Kmemleak does not play well with KASAN (tested on both HPE Apollo 70 and
Huawei TaiShan 2280 aarch64 servers).

After calling start_kernel()->setup_arch()->kasan_init(), kmemleak early
log buffer went from something like 280 to 260000 which caused kmemleak
disabled and crash dump memory reservation failed.  The multitude of
kmemleak_alloc() calls is from nested loops while KASAN is setting up full
memory mappings, so let early kmemleak allocations skip those
memblock_alloc_internal() calls came from kasan_init() given that those
early KASAN memory mappings should not reference to other memory.  Hence,
no kmemleak false positives.

kasan_init
  kasan_map_populate [1]
    kasan_pgd_populate [2]
      kasan_pud_populate [3]
        kasan_pmd_populate [4]
          kasan_pte_populate [5]
            kasan_alloc_zeroed_page
              memblock_alloc_try_nid
                memblock_alloc_internal
                  kmemleak_alloc

[1] for_each_memblock(memory, reg)
[2] while (pgdp++, addr = next, addr != end)
[3] while (pudp++, addr = next, addr != end && pud_none(READ_ONCE(*pudp)))
[4] while (pmdp++, addr = next, addr != end && pmd_none(READ_ONCE(*pmdp)))
[5] while (ptep++, addr = next, addr != end && pte_none(READ_ONCE(*ptep)))

Link: http://lkml.kernel.org/r/1543442925-17794-1-git-send-email-cai@gmx.us
Signed-off-by: Qian Cai <cai@gmx.us>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Qian Cai 2018-12-28 00:36:29 -08:00 committed by Linus Torvalds
parent 65c7878413
commit fed84c7852
3 changed files with 13 additions and 9 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

2
arch/arm64/mm/kasan_init.c
View file

@ -39,7 +39,7 @@ static phys_addr_t __init kasan_alloc_zeroed_page(int node)
{
void *p = memblock_alloc_try_nid(PAGE_SIZE, PAGE_SIZE,
__pa(MAX_DMA_ADDRESS),
MEMBLOCK_ALLOC_ACCESSIBLE, node);
MEMBLOCK_ALLOC_KASAN, node);
return __pa(p);
}

1
include/linux/memblock.h
View file

@ -319,6 +319,7 @@ static inline int memblock_get_region_node(const struct memblock_region *r)
/* Flags for memblock allocation APIs */
#define MEMBLOCK_ALLOC_ANYWHERE (~(phys_addr_t)0)
#define MEMBLOCK_ALLOC_ACCESSIBLE 0
#define MEMBLOCK_ALLOC_KASAN 1
/* We are using top down, so it is safe to use 0 here */
#define MEMBLOCK_LOW_LIMIT 0

19
mm/memblock.c
View file

@ -262,7 +262,8 @@ phys_addr_t __init_memblock memblock_find_in_range_node(phys_addr_t size,
phys_addr_t kernel_end, ret;
/* pump up @end */
if (end == MEMBLOCK_ALLOC_ACCESSIBLE)
if (end == MEMBLOCK_ALLOC_ACCESSIBLE ||
end == MEMBLOCK_ALLOC_KASAN)
end = memblock.current_limit;
/* avoid allocating the first page */
@ -1419,13 +1420,15 @@ static void * __init memblock_alloc_internal(
done:
ptr = phys_to_virt(alloc);
/*
* The min_count is set to 0 so that bootmem allocated blocks
* are never reported as leaks. This is because many of these blocks
* are only referred via the physical address which is not
* looked up by kmemleak.
*/
kmemleak_alloc(ptr, size, 0, 0);
/* Skip kmemleak for kasan_init() due to high volume. */
if (max_addr != MEMBLOCK_ALLOC_KASAN)
/*
* The min_count is set to 0 so that bootmem allocated
* blocks are never reported as leaks. This is because many
* of these blocks are only referred via the physical
* address which is not looked up by kmemleak.
*/
kmemleak_alloc(ptr, size, 0, 0);
return ptr;
}