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

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>

diff --git a/arch/arm64/mm/kasan_init.c b/arch/arm64/mm/kasan_init.c
index 3e142ad..4b55b15 100644 (file)
--- a/arch/arm64/mm/kasan_init.c
+++ b/arch/arm64/mm/kasan_init.c
@@ -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);
 }
 

diff --git a/include/linux/memblock.h b/include/linux/memblock.h
index 5f74ba6..64c41cf 100644 (file)
--- a/include/linux/memblock.h
+++ b/include/linux/memblock.h
@@ -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

diff --git a/mm/memblock.c b/mm/memblock.c
index f57d762..022d4cb 100644 (file)
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -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 @@ again:
 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;
 }