Re: [patches] [PATCH] [15/50] x86_64: Return EINVAL forunknown addressin change_page_attr

[Jan Beulich]

This should be accompanied by

 			addr2 = __START_KERNEL_map + __pa(address);
 			/* Make sure the kernel mappings stay executable */
 			prot2 = pte_pgprot(pte_mkexec(pfn_pte(0, prot)));
-			err = __change_page_attr(addr2, pfn, prot2,
+			(void)__change_page_attr(addr2, pfn, prot2,
 						 kref_prot(addr2));
 		} 
 	} 	

as otherwise it is non-obvious why there's no check of err (which so far really
was missing). The reason this must be tolerated here is free_init_pages()/
free_initmem() removing the translation for the affected kernel image pages
altogether.

Jan

>>> Andi Kleen <ak@xxxxxxx> 22.09.07 00:32 >>>

Matches what i386 does and makes more sense.

Signed-off-by: Andi Kleen <ak@xxxxxxx>

---
 arch/x86_64/mm/pageattr.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

Index: linux/arch/x86_64/mm/pageattr.c
===================================================================
--- linux.orig/arch/x86_64/mm/pageattr.c
+++ linux/arch/x86_64/mm/pageattr.c
@@ -151,7 +151,9 @@ __change_page_attr(unsigned long address
 	pgprot_t ref_prot2;
 
 	kpte = lookup_address(address);
-	if (!kpte) return 0;
+	if (!kpte)
+		return -EINVAL;
+
 	kpte_page = virt_to_page(((unsigned long)kpte) & PAGE_MASK);
 	BUG_ON(PageCompound(kpte_page));
 	BUG_ON(PageLRU(kpte_page));
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