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Commit 88299f64 authored by Qian Cai's avatar Qian Cai Committed by Alistair Delva
Browse files

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

(Upstream commit fed84c78527009d4f799a3ed9a566502fa026d82).

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: default avatarQian Cai <cai@gmx.us>
Acked-by: default avatarCatalin 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: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
Change-Id: I2423d511c3938c882c738341673b13b3beff5475
Signed-off-by: default avatarAndrey Konovalov <andreyknvl@google.com>
Bug: 128674696
parent f7de9038

arch/arm64/mm/kasan_init.c

+1 −1
Original line number Original line Diff line number Diff line
@@ -40,7 +40,7 @@ static phys_addr_t __init kasan_alloc_zeroed_page(int node) 
{

{

	void *p = memblock_virt_alloc_try_nid(PAGE_SIZE, PAGE_SIZE,

	void *p = memblock_virt_alloc_try_nid(PAGE_SIZE, PAGE_SIZE,

					      __pa(MAX_DMA_ADDRESS),

					      __pa(MAX_DMA_ADDRESS),

					      MEMBLOCK_ALLOC_ACCESSIBLE, node);

					      MEMBLOCK_ALLOC_KASAN, node);

	return __pa(p);

	return __pa(p);

}

}

include/linux/memblock.h

+1 −0
Original line number Original line Diff line number Diff line
@@ -342,6 +342,7 @@ static inline bool memblock_bottom_up(void) 
/* Flags for memblock_alloc_base() amd __memblock_alloc_base() */

/* Flags for memblock_alloc_base() amd __memblock_alloc_base() */

#define MEMBLOCK_ALLOC_ANYWHERE	(~(phys_addr_t)0)

#define MEMBLOCK_ALLOC_ANYWHERE	(~(phys_addr_t)0)

#define MEMBLOCK_ALLOC_ACCESSIBLE	0

#define MEMBLOCK_ALLOC_ACCESSIBLE	0

#define MEMBLOCK_ALLOC_KASAN		1





phys_addr_t __init memblock_alloc_range(phys_addr_t size, phys_addr_t align,

phys_addr_t __init memblock_alloc_range(phys_addr_t size, phys_addr_t align,

					phys_addr_t start, phys_addr_t end,

					phys_addr_t start, phys_addr_t end,

mm/memblock.c

+11 −8
Original line number Original line Diff line number Diff line
@@ -253,7 +253,8 @@ phys_addr_t __init_memblock memblock_find_in_range_node(phys_addr_t size, 
	phys_addr_t kernel_end, ret;

	phys_addr_t kernel_end, ret;





	/* pump up @end */

	/* pump up @end */

	if (end == MEMBLOCK_ALLOC_ACCESSIBLE)

	if (end == MEMBLOCK_ALLOC_ACCESSIBLE ||

	    end == MEMBLOCK_ALLOC_KASAN)

		end = memblock.current_limit;

		end = memblock.current_limit;





	/* avoid allocating the first page */

	/* avoid allocating the first page */
@@ -1401,11 +1402,13 @@ static void * __init memblock_virt_alloc_internal( 
done:

done:

	ptr = phys_to_virt(alloc);

	ptr = phys_to_virt(alloc);





	/* 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

		 * The min_count is set to 0 so that bootmem allocated

	 * are never reported as leaks. This is because many of these blocks

		 * blocks are never reported as leaks. This is because many

	 * are only referred via the physical address which is not

		 * of these blocks are only referred via the physical

	 * looked up by kmemleak.

		 * address which is not looked up by kmemleak.

		 */

		 */

		kmemleak_alloc(ptr, size, 0, 0);

		kmemleak_alloc(ptr, size, 0, 0);