mm/memblock.c: skip kmemleak for kasan_init() (fed84c78) · Commits · 戴 / test

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>

arch/arm64/mm/kasan_init.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -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);
		}

include/linux/memblock.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -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

mm/memblock.c

+11 −8

Original line number	Diff line number	Diff line
		@@ -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 */
		@@ -1419,11 +1420,13 @@ again:
		done:
		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
		* 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.
		* 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);

Admin message