Xiaotian Feng a Ãcrit :
On Thu, Dec 23, 2010 at 5:35 AM, <Valdis.Kletnieks@xxxxxx> wrote:
On Wed, 22 Dec 2010 13:40:19 +0100, Ingo Molnar said:
* mat <castet.matthieu@xxxxxxx> wrote:
Le Wed, 8 Dec 2010 14:19:51 -0800,
Kees Cook <kees.cook@xxxxxxxxxxxxx> a Ãcrit :
On Fri, Nov 26, 2010 at 06:23:55PM +0100, mat wrote:
could you try the attached patch ?
on module load, we sort the __jump_table section. So we should make
it writable.
Matthieu
diff --git a/arch/x86/include/asm/jump_label.h
b/arch/x86/include/asm/jump_label.h index f52d42e..574dbc2 100644
--- a/arch/x86/include/asm/jump_label.h
+++ b/arch/x86/include/asm/jump_label.h
@@ -14,7 +14,7 @@
do
{ \ asm
goto("1:" \
JUMP_LABEL_INITIAL_NOP \
- ".pushsection __jump_table, \"a\" \n\t"\
+ ".pushsection __jump_table, \"aw\" \n\t"\
_ASM_PTR "1b, %l[" #label "], %c0 \n\t" \
".popsection \n\t" \
: : "i" (key) : : label);
\
Acked-by: Kees Cook <kees.cook@xxxxxxxxxxxxx>
Can this please get committed to tip?
I think it is not need anymore with Steven Rostedt patch [1]
Matthieu
[1]
Here we set the text read only before we call the notifiers. The
function tracer changes the calls to mcount into nops via a notifier
call so this must be done after the module notifiers.
What's the status of this bug?
If we still need the patch then please submit it standalone with a proper subject
line, with acks/signoffs added, etc.
Steve Rostedt's patch that moves the setting of the page permissions seems to
make this patch no longer necessary. I tripped over this same issue, but the
version in the latest -mmotm does not need it, as it includes Steve's fix.
I'm facing a boot failure (panic'ed on remove_jump_label_module_init)
on 2.6.37 (latest commit 3c0cb7c), which is 100% reproducible.
With this patch applied, I can boot my machine successfully, so I do
think this patch is needed.
Could you confirm that this patch fix the problem ?
Matthieu
>From 0eeba453aaba0ebff86f0a7ad9bfb8afbde0c0dc Mon Sep 17 00:00:00 2001
From: Matthieu CASTET <castet.matthieu@xxxxxxx>
Date: Thu, 20 Jan 2011 21:25:03 +0100
Subject: [PATCH] Fix jump table in module init section
If we use jump table in module init, there are marked
as removed in __jump_table section after init is done.
But we already applied ro permissions on the module, so
we can't modify a read only section (crash in
remove_jump_label_module_init).
Make the __jump_table section rw.
Signed-off-by: Matthieu CASTET <castet.matthieu@xxxxxxx>
---
arch/x86/include/asm/jump_label.h | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/arch/x86/include/asm/jump_label.h b/arch/x86/include/asm/jump_label.h
index f52d42e..574dbc2 100644
--- a/arch/x86/include/asm/jump_label.h
+++ b/arch/x86/include/asm/jump_label.h
@@ -14,7 +14,7 @@
do { \
asm goto("1:" \
JUMP_LABEL_INITIAL_NOP \
- ".pushsection __jump_table, \"a\" \n\t"\
+ ".pushsection __jump_table, \"aw\" \n\t"\
_ASM_PTR "1b, %l[" #label "], %c0 \n\t" \
".popsection \n\t" \
: : "i" (key) : : label); \
--
1.7.2.3
