Commit acb9cd81 authored May 10, 2019 by qqzhou

arm: mm: init: check for upper PAGE_SHIFT bits in pfn_valid()



If the pfn passed is too big and invalid, the checks in
pfn_valid() will pass because it misses to check overflow.
This will cause that calculated page pointer is overflow and
invalid, then kernel panic happens. Add checks for pfn overflow
in pfn_valid().

Change-Id: I461fb5db8de52f2249b4f70f188d6c5bfe6902f4
Signed-off-by: qqzhou <qqzhou@codeaurora.org>

parent 4d705047

arch/arm/mm/init.c

+5 −1

Original line number	Diff line number	Diff line
		@@ -192,7 +192,11 @@ static void __init zone_sizes_init(unsigned long min, unsigned long max_low,
		#ifdef CONFIG_HAVE_ARCH_PFN_VALID
		int pfn_valid(unsigned long pfn)
		{
		return memblock_is_map_memory(__pfn_to_phys(pfn));
		phys_addr_t addr = __pfn_to_phys(pfn);

		if (__phys_to_pfn(addr) != pfn)
		return 0;
		return memblock_is_map_memory(addr);
		}
		EXPORT_SYMBOL(pfn_valid);
		#endif