Only force RO in the advisory protection checks when all pages in the
range are RO. Previously it would trigger when any page in the range
was ro.
I believe this will make try_preserve_large_page much safer to use.
Signed-off-by: Andi Kleen <ak@suse.de>
---
arch/x86/mm/pageattr.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
Index: linux/arch/x86/mm/pageattr.c
===================================================================
--- linux.orig/arch/x86/mm/pageattr.c
+++ linux/arch/x86/mm/pageattr.c
@@ -193,14 +193,16 @@ advised_static_prot(pgprot_t prot, unsig
pgprot_t forbidden = __pgprot(0);
/* The .rodata section needs to be read-only */
- if (within_range(start, end, (unsigned long)__start_rodata,
- (unsigned long)__end_rodata))
+ if (within_range((unsigned long)__start_rodata,
+ (unsigned long)__end_rodata,
+ start, end))
pgprot_val(forbidden) |= _PAGE_RW;
/*
* Do the same for the x86-64 high kernel mapping
*/
- if (within_range(start, end, virt_to_highmap(__start_rodata),
- virt_to_highmap(__end_rodata)))
+ if (within_range(virt_to_highmap(__start_rodata),
+ virt_to_highmap(__end_rodata),
+ start, end))
pgprot_val(forbidden) |= _PAGE_RW;
prot = __pgprot(pgprot_val(prot) & ~pgprot_val(forbidden));
--
