Re: -tip tree resume fail, bisect to 5bd5a45(x86: Add NXprotection for kernel data)

From: Peter Zijlstra
Date: Mon Nov 22 2010 - 08:03:28 EST


On Mon, 2010-11-22 at 15:23 +0800, Lin Ming wrote:
> Hi, all
>
> Current -tip tree(92c883a) fail to resume after suspend to mem.
> Bisect to commit 5bd5a45(x86: Add NX protection for kernel data).

Drad, if only I'd looked at LKML before I did the bisection myself..

> commit 5bd5a452662bc37c54fb6828db1a3faf87e6511c
> Author: Matthieu Castet <castet.matthieu@xxxxxxx>
> Date: Tue Nov 16 22:31:26 2010 +0100
>
> x86: Add NX protection for kernel data
>
>
> I did some debug and found the regression is caused by below line.
>
> - set_memory_nx(rodata_start, (end - rodata_start) >> PAGE_SHIFT);
> + set_memory_nx(rodata_start, (kernel_end - rodata_start) >> PAGE_SHIFT);


Confirmed, with that hunk reverted my machine works again..

---
arch/x86/mm/init_64.c | 3 +--
1 files changed, 1 insertions(+), 2 deletions(-)

diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index ce59c05..71a5929 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -788,7 +788,6 @@ void mark_rodata_ro(void)
unsigned long rodata_start =
((unsigned long)__start_rodata + PAGE_SIZE - 1) & PAGE_MASK;
unsigned long end = (unsigned long) &__end_rodata_hpage_align;
- unsigned long kernel_end = (((unsigned long)&__init_end + HPAGE_SIZE) & HPAGE_MASK);
unsigned long text_end = PAGE_ALIGN((unsigned long) &__stop___ex_table);
unsigned long rodata_end = PAGE_ALIGN((unsigned long) &__end_rodata);
unsigned long data_start = (unsigned long) &_sdata;
@@ -803,7 +802,7 @@ void mark_rodata_ro(void)
* The rodata section (but not the kernel text!) should also be
* not-executable.
*/
- set_memory_nx(rodata_start, (kernel_end - rodata_start) >> PAGE_SHIFT);
+ set_memory_nx(rodata_start, (end - rodata_start) >> PAGE_SHIFT);

rodata_test();


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