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Commit 3b17979b authored by Jeremy Fitzhardinge's avatar Jeremy Fitzhardinge Committed by Linus Torvalds
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[PATCH] Fix kunmap_atomic's use of kpte_clear_flush() 



kunmap_atomic() will call kpte_clear_flush with vaddr/ptep arguments which
don't correspond if the vaddr is just a normal lowmem address (ie, not in
the KMAP area).  This patch makes sure that the pte is only cleared if kmap
area was actually used for the mapping.

Signed-off-by: default avatarJeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
Cc: Zachary Amsden <zach@vmware.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent ad76fb6b

arch/i386/mm/highmem.c

+8 −10
Original line number Diff line number Diff line
@@ -50,22 +50,20 @@ void kunmap_atomic(void *kvaddr, enum km_type type) 
	unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;

	enum fixed_addresses idx = type + KM_TYPE_NR*smp_processor_id();



#ifdef CONFIG_DEBUG_HIGHMEM

	if (vaddr >= PAGE_OFFSET && vaddr < (unsigned long)high_memory) {

		pagefault_enable();

		return;

	}



	if (vaddr != __fix_to_virt(FIX_KMAP_BEGIN+idx))

		BUG();

#endif

	/*

	 * Force other mappings to Oops if they'll try to access this pte

	 * without first remap it.  Keeping stale mappings around is a bad idea

	 * also, in case the page changes cacheability attributes or becomes

	 * a protected page in a hypervisor.

	 */

	if (vaddr == __fix_to_virt(FIX_KMAP_BEGIN+idx))

		kpte_clear_flush(kmap_pte-idx, vaddr);

	else {

#ifdef CONFIG_DEBUG_HIGHMEM

		BUG_ON(vaddr < PAGE_OFFSET);

		BUG_ON(vaddr >= (unsigned long)high_memory);

#endif

	}



	pagefault_enable();

}