* [PATCH][v3.2] Revert: x86, 64bit, mm: Mark data/bss/brk to nx
@ 2015-01-19 21:49 Steven Rostedt
2015-01-19 22:07 ` Ben Hutchings
0 siblings, 1 reply; 5+ messages in thread
From: Steven Rostedt @ 2015-01-19 21:49 UTC (permalink / raw)
To: Ben Hutchings; +Cc: LKML, stable, Yinghai Lu, H. Peter Anvin
Testing v3.2-rt I found that after merging the latest v3.2 stable tree,
hotplug stopped working. I tested the latest v3.2 stable, and it was
not working there either. I bisected it down to:
commit e105c8187b7101e8a8a54ac0218c9d9c9463c636
Author: Yinghai Lu <yinghai@kernel.org>
Date: Thu Jan 24 12:20:13 2013 -0800
x86, 64bit, mm: Mark data/bss/brk to nx
commit 72212675d1c96f5db8ec6fb35701879911193158 upstream.
Simply doing:
# echo 0 > /sys/devices/system/cpu/cpu1/online
# echo 1 > /sys/devices/system/cpu/cpu1/online
caused the system to reboot.
After reverting that commit, hotplug works again on the v3.2 stable
tree.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index 266f71719e42..783eba48d00c 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -778,7 +778,6 @@ void mark_rodata_ro(void)
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;
- unsigned long all_end;
printk(KERN_INFO "Write protecting the kernel read-only data: %luk\n",
(end - start) >> 10);
@@ -787,8 +786,8 @@ void mark_rodata_ro(void)
kernel_set_to_readonly = 1;
/*
- * The rodata/data/bss/brk section (but not the kernel text!)
- * should also be not-executable.
+ * The rodata section (but not the kernel text!) should also be
+ * not-executable.
*
* We align all_end to PMD_SIZE because the existing mapping
* is a full PMD. If we would align _brk_end to PAGE_SIZE we
@@ -798,8 +797,7 @@ void mark_rodata_ro(void)
* Any PMD which was setup after the one which covers _brk_end
* has been zapped already via cleanup_highmem().
*/
- all_end = roundup((unsigned long)_brk_end, PMD_SIZE);
- set_memory_nx(rodata_start, (all_end - rodata_start) >> PAGE_SHIFT);
+ set_memory_nx(rodata_start, (end - rodata_start) >> PAGE_SHIFT);
rodata_test();
^ permalink raw reply related [flat|nested] 5+ messages in thread* Re: [PATCH][v3.2] Revert: x86, 64bit, mm: Mark data/bss/brk to nx
2015-01-19 21:49 [PATCH][v3.2] Revert: x86, 64bit, mm: Mark data/bss/brk to nx Steven Rostedt
@ 2015-01-19 22:07 ` Ben Hutchings
2015-01-19 22:19 ` Steven Rostedt
0 siblings, 1 reply; 5+ messages in thread
From: Ben Hutchings @ 2015-01-19 22:07 UTC (permalink / raw)
To: Steven Rostedt; +Cc: LKML, stable, Yinghai Lu, H. Peter Anvin
[-- Attachment #1: Type: text/plain, Size: 2461 bytes --]
On Mon, 2015-01-19 at 16:49 -0500, Steven Rostedt wrote:
> Testing v3.2-rt I found that after merging the latest v3.2 stable tree,
> hotplug stopped working. I tested the latest v3.2 stable, and it was
> not working there either. I bisected it down to:
>
> commit e105c8187b7101e8a8a54ac0218c9d9c9463c636
> Author: Yinghai Lu <yinghai@kernel.org>
> Date: Thu Jan 24 12:20:13 2013 -0800
>
> x86, 64bit, mm: Mark data/bss/brk to nx
>
> commit 72212675d1c96f5db8ec6fb35701879911193158 upstream.
>
> Simply doing:
>
> # echo 0 > /sys/devices/system/cpu/cpu1/online
> # echo 1 > /sys/devices/system/cpu/cpu1/online
>
> caused the system to reboot.
>
> After reverting that commit, hotplug works again on the v3.2 stable
> tree.
Yes, I know this needs fixing. It also broke suspend/resume on SMP
machines since that involves offlining and onlining CPUs 1-n.
Ben.
> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
> ---
> diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
> index 266f71719e42..783eba48d00c 100644
> --- a/arch/x86/mm/init_64.c
> +++ b/arch/x86/mm/init_64.c
> @@ -778,7 +778,6 @@ void mark_rodata_ro(void)
> 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;
> - unsigned long all_end;
>
> printk(KERN_INFO "Write protecting the kernel read-only data: %luk\n",
> (end - start) >> 10);
> @@ -787,8 +786,8 @@ void mark_rodata_ro(void)
> kernel_set_to_readonly = 1;
>
> /*
> - * The rodata/data/bss/brk section (but not the kernel text!)
> - * should also be not-executable.
> + * The rodata section (but not the kernel text!) should also be
> + * not-executable.
> *
> * We align all_end to PMD_SIZE because the existing mapping
> * is a full PMD. If we would align _brk_end to PAGE_SIZE we
> @@ -798,8 +797,7 @@ void mark_rodata_ro(void)
> * Any PMD which was setup after the one which covers _brk_end
> * has been zapped already via cleanup_highmem().
> */
> - all_end = roundup((unsigned long)_brk_end, PMD_SIZE);
> - set_memory_nx(rodata_start, (all_end - rodata_start) >> PAGE_SHIFT);
> + set_memory_nx(rodata_start, (end - rodata_start) >> PAGE_SHIFT);
>
> rodata_test();
>
--
Ben Hutchings
Larkinson's Law: All laws are basically false.
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^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH][v3.2] Revert: x86, 64bit, mm: Mark data/bss/brk to nx
2015-01-19 22:07 ` Ben Hutchings
@ 2015-01-19 22:19 ` Steven Rostedt
2015-01-20 16:06 ` Ben Hutchings
0 siblings, 1 reply; 5+ messages in thread
From: Steven Rostedt @ 2015-01-19 22:19 UTC (permalink / raw)
To: Ben Hutchings; +Cc: LKML, stable, Yinghai Lu, H. Peter Anvin
On Mon, 19 Jan 2015 22:07:11 +0000
Ben Hutchings <ben@decadent.org.uk> wrote:
> Yes, I know this needs fixing. It also broke suspend/resume on SMP
> machines since that involves offlining and onlining CPUs 1-n.
OK, as long as you know. Also, have you seen my other patch?
http://marc.info/?l=linux-kernel&m=142150909924885
-- Steve
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH][v3.2] Revert: x86, 64bit, mm: Mark data/bss/brk to nx
2015-01-19 22:19 ` Steven Rostedt
@ 2015-01-20 16:06 ` Ben Hutchings
2015-01-20 16:12 ` Steven Rostedt
0 siblings, 1 reply; 5+ messages in thread
From: Ben Hutchings @ 2015-01-20 16:06 UTC (permalink / raw)
To: Steven Rostedt; +Cc: LKML, stable, Yinghai Lu, H. Peter Anvin
[-- Attachment #1: Type: text/plain, Size: 588 bytes --]
On Mon, 2015-01-19 at 17:19 -0500, Steven Rostedt wrote:
> On Mon, 19 Jan 2015 22:07:11 +0000
> Ben Hutchings <ben@decadent.org.uk> wrote:
>
> > Yes, I know this needs fixing. It also broke suspend/resume on SMP
> > machines since that involves offlining and onlining CPUs 1-n.
>
> OK, as long as you know. Also, have you seen my other patch?
>
> http://marc.info/?l=linux-kernel&m=142150909924885
Yes, I saw that and have filed it away for whenever I start working on
the next 3.2 release.
Ben.
--
Ben Hutchings
Larkinson's Law: All laws are basically false.
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^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH][v3.2] Revert: x86, 64bit, mm: Mark data/bss/brk to nx
2015-01-20 16:06 ` Ben Hutchings
@ 2015-01-20 16:12 ` Steven Rostedt
0 siblings, 0 replies; 5+ messages in thread
From: Steven Rostedt @ 2015-01-20 16:12 UTC (permalink / raw)
To: Ben Hutchings; +Cc: LKML, stable, Yinghai Lu, H. Peter Anvin
On Tue, 20 Jan 2015 16:06:06 +0000
Ben Hutchings <ben@decadent.org.uk> wrote:
> On Mon, 2015-01-19 at 17:19 -0500, Steven Rostedt wrote:
> > On Mon, 19 Jan 2015 22:07:11 +0000
> > Ben Hutchings <ben@decadent.org.uk> wrote:
> >
> > > Yes, I know this needs fixing. It also broke suspend/resume on SMP
> > > machines since that involves offlining and onlining CPUs 1-n.
> >
> > OK, as long as you know. Also, have you seen my other patch?
> >
> > http://marc.info/?l=linux-kernel&m=142150909924885
>
> Yes, I saw that and have filed it away for whenever I start working on
> the next 3.2 release.
OK,
I'm going to hold off releasing another 3.2-rt until then.
-- Steve
^ permalink raw reply [flat|nested] 5+ messages in thread
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2015-01-19 21:49 [PATCH][v3.2] Revert: x86, 64bit, mm: Mark data/bss/brk to nx Steven Rostedt
2015-01-19 22:07 ` Ben Hutchings
2015-01-19 22:19 ` Steven Rostedt
2015-01-20 16:06 ` Ben Hutchings
2015-01-20 16:12 ` Steven Rostedt
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