Commit e3100c82 authored Feb 27, 2008 by Thomas Gleixner Committed by Ingo Molnar Apr 17, 2008

x86: check physical address range in ioremap

Roland Dreier reported in http://lkml.org/lkml/2008/2/27/194



[ 8425.915139] BUG: unable to handle kernel paging request at ffffc20001a0a000
[ 8425.919087] IP: [<ffffffff8021dacc>] clflush_cache_range+0xc/0x25
[ 8425.919087] PGD 1bf80e067 PUD 1bf80f067 PMD 1bb497067 PTE 80000047000ee17b

This is on a Intel machine with 36bit physical address space. The PTE
entry references 47000ee000, which is outside of it.

Add a check for the physical address space and warn/printk about the
stupid caller.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

parent b8c2d3df

arch/x86/mm/ioremap.c

+19 −0

Original line number	Diff line number	Diff line
		@@ -35,6 +35,18 @@ unsigned long __phys_addr(unsigned long x)
		}
		EXPORT_SYMBOL(__phys_addr);

		static inline int phys_addr_valid(unsigned long addr)
		{
		return addr < (1UL << boot_cpu_data.x86_phys_bits);
		}

		#else

		static inline int phys_addr_valid(unsigned long addr)
		{
		return 1;
		}

		#endif

		int page_is_ram(unsigned long pagenr)
		@@ -118,6 +130,13 @@ static void __iomem *__ioremap(resource_size_t phys_addr, unsigned long size,
		if (!size \|\| last_addr < phys_addr)
		return NULL;

		if (!phys_addr_valid(phys_addr)) {
		printk(KERN_WARNING "ioremap: invalid physical address %lx\n",
		phys_addr);
		WARN_ON_ONCE(1);
		return NULL;
		}

		/*
		* Don't remap the low PCI/ISA area, it's always mapped..
		*/