* [PATCH] powerpc: Make alignment exception always check exception table (#2)
2006-11-01 3:09 [PATCH] powerpc: Make alignment exception always check exception table Benjamin Herrenschmidt
@ 2006-11-01 3:42 ` Benjamin Herrenschmidt
2006-11-01 4:11 ` [PATCH] powerpc: Make alignment exception always check exception table (#3) Benjamin Herrenschmidt
2006-11-01 6:34 ` [PATCH] powerpc: Make alignment exception always check exception table Greg KH
2 siblings, 0 replies; 5+ messages in thread
From: Benjamin Herrenschmidt @ 2006-11-01 3:42 UTC (permalink / raw)
To: Paul Mackerras; +Cc: linuxppc-dev list, Greg KH
The alignment exception used to only check the exception table for
-EFAULT, not for other errors. That opens an oops window if we can
coerce the kernel into getting an alignment exception for other reasons
in what would normally be a user-protected accessor, which can be done
via some of the futex ops. This fixes it by always checking the
exception tables.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
---
Paul: this version also fixes arch/ppc
This is 2.6.19 material and should probably go into stable as well.
(Greg: take it if paulus acks it and it applies :)
Index: linux-work/arch/powerpc/kernel/traps.c
===================================================================
--- linux-work.orig/arch/powerpc/kernel/traps.c 2006-10-23 14:41:37.000000000 +1000
+++ linux-work/arch/powerpc/kernel/traps.c 2006-10-30 13:59:41.000000000 +1100
@@ -843,7 +843,7 @@ void __kprobes program_check_exception(s
void alignment_exception(struct pt_regs *regs)
{
- int fixed = 0;
+ int sig, fixed = 0;
/* we don't implement logging of alignment exceptions */
if (!(current->thread.align_ctl & PR_UNALIGN_SIGBUS))
@@ -856,15 +856,11 @@ void alignment_exception(struct pt_regs
}
/* Operand address was bad */
- if (fixed == -EFAULT) {
- if (user_mode(regs))
- _exception(SIGSEGV, regs, SEGV_ACCERR, regs->dar);
- else
- /* Search exception table */
- bad_page_fault(regs, regs->dar, SIGSEGV);
- return;
- }
- _exception(SIGBUS, regs, BUS_ADRALN, regs->dar);
+ sig = fixed == -EFAULT ? SIGSEGV : SIGBUS;
+ if (user_mode(regs))
+ _exception(sig, regs, SEGV_ACCERR, regs->dar);
+ else
+ bad_page_fault(regs, regs->dar, sig);
}
void StackOverflow(struct pt_regs *regs)
Index: linux-work/arch/ppc/kernel/traps.c
===================================================================
--- linux-work.orig/arch/ppc/kernel/traps.c 2006-10-06 13:47:55.000000000 +1000
+++ linux-work/arch/ppc/kernel/traps.c 2006-11-01 14:39:44.000000000 +1100
@@ -708,7 +708,7 @@ void single_step_exception(struct pt_reg
void alignment_exception(struct pt_regs *regs)
{
- int fixed;
+ int sig, fixed = 0;
fixed = fix_alignment(regs);
if (fixed == 1) {
@@ -716,15 +716,11 @@ void alignment_exception(struct pt_regs
emulate_single_step(regs);
return;
}
- if (fixed == -EFAULT) {
- /* fixed == -EFAULT means the operand address was bad */
- if (user_mode(regs))
- _exception(SIGSEGV, regs, SEGV_ACCERR, regs->dar);
- else
- bad_page_fault(regs, regs->dar, SIGSEGV);
- return;
- }
- _exception(SIGBUS, regs, BUS_ADRALN, regs->dar);
+ sig = fixed == -EFAULT ? SIGSEGV : SIGBUS;
+ if (user_mode(regs))
+ _exception(sig, regs, SEGV_ACCERR, regs->dar);
+ else
+ bad_page_fault(regs, regs->dar, sig);
}
void StackOverflow(struct pt_regs *regs)
^ permalink raw reply [flat|nested] 5+ messages in thread* [PATCH] powerpc: Make alignment exception always check exception table (#3)
2006-11-01 3:09 [PATCH] powerpc: Make alignment exception always check exception table Benjamin Herrenschmidt
2006-11-01 3:42 ` [PATCH] powerpc: Make alignment exception always check exception table (#2) Benjamin Herrenschmidt
@ 2006-11-01 4:11 ` Benjamin Herrenschmidt
2006-11-01 6:34 ` [PATCH] powerpc: Make alignment exception always check exception table Greg KH
2 siblings, 0 replies; 5+ messages in thread
From: Benjamin Herrenschmidt @ 2006-11-01 4:11 UTC (permalink / raw)
To: Paul Mackerras; +Cc: linuxppc-dev list, Greg KH
The alignment exception used to only check the exception table for
-EFAULT, not for other errors. That opens an oops window if we can
coerce the kernel into getting an alignment exception for other reasons
in what would normally be a user-protected accessor, which can be done
via some of the futex ops. This fixes it by always checking the
exception tables.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
---
Paul: this version sets the correct si_code
This is 2.6.19 material and should probably go into stable as well.
(Greg: take it if paulus acks it and it applies :)
Index: linux-work/arch/powerpc/kernel/traps.c
===================================================================
--- linux-work.orig/arch/powerpc/kernel/traps.c 2006-11-01 14:59:07.000000000 +1100
+++ linux-work/arch/powerpc/kernel/traps.c 2006-11-01 15:01:06.000000000 +1100
@@ -843,7 +843,7 @@ void __kprobes program_check_exception(s
void alignment_exception(struct pt_regs *regs)
{
- int fixed = 0;
+ int sig, code, fixed = 0;
/* we don't implement logging of alignment exceptions */
if (!(current->thread.align_ctl & PR_UNALIGN_SIGBUS))
@@ -857,14 +857,16 @@ void alignment_exception(struct pt_regs
/* Operand address was bad */
if (fixed == -EFAULT) {
- if (user_mode(regs))
- _exception(SIGSEGV, regs, SEGV_ACCERR, regs->dar);
- else
- /* Search exception table */
- bad_page_fault(regs, regs->dar, SIGSEGV);
- return;
+ sig = SIGSEGV;
+ code = SEGV_ACCERR;
+ } else {
+ sig = SIGBUS;
+ code = BUS_ADRALN;
}
- _exception(SIGBUS, regs, BUS_ADRALN, regs->dar);
+ if (user_mode(regs))
+ _exception(sig, regs, code, regs->dar);
+ else
+ bad_page_fault(regs, regs->dar, sig);
}
void StackOverflow(struct pt_regs *regs)
Index: linux-work/arch/ppc/kernel/traps.c
===================================================================
--- linux-work.orig/arch/ppc/kernel/traps.c 2006-11-01 14:59:07.000000000 +1100
+++ linux-work/arch/ppc/kernel/traps.c 2006-11-01 15:01:32.000000000 +1100
@@ -708,7 +708,7 @@ void single_step_exception(struct pt_reg
void alignment_exception(struct pt_regs *regs)
{
- int fixed;
+ int sig, code, fixed = 0;
fixed = fix_alignment(regs);
if (fixed == 1) {
@@ -717,14 +717,16 @@ void alignment_exception(struct pt_regs
return;
}
if (fixed == -EFAULT) {
- /* fixed == -EFAULT means the operand address was bad */
- if (user_mode(regs))
- _exception(SIGSEGV, regs, SEGV_ACCERR, regs->dar);
- else
- bad_page_fault(regs, regs->dar, SIGSEGV);
- return;
+ sig = SIGSEGV;
+ code = SEGV_ACCERR;
+ } else {
+ sig = SIGBUS;
+ code = BUS_ADRALN;
}
- _exception(SIGBUS, regs, BUS_ADRALN, regs->dar);
+ if (user_mode(regs))
+ _exception(sig, regs, code, regs->dar);
+ else
+ bad_page_fault(regs, regs->dar, sig);
}
void StackOverflow(struct pt_regs *regs)
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH] powerpc: Make alignment exception always check exception table
2006-11-01 3:09 [PATCH] powerpc: Make alignment exception always check exception table Benjamin Herrenschmidt
2006-11-01 3:42 ` [PATCH] powerpc: Make alignment exception always check exception table (#2) Benjamin Herrenschmidt
2006-11-01 4:11 ` [PATCH] powerpc: Make alignment exception always check exception table (#3) Benjamin Herrenschmidt
@ 2006-11-01 6:34 ` Greg KH
2006-11-01 20:43 ` Benjamin Herrenschmidt
2 siblings, 1 reply; 5+ messages in thread
From: Greg KH @ 2006-11-01 6:34 UTC (permalink / raw)
To: Benjamin Herrenschmidt; +Cc: linuxppc-dev list, Paul Mackerras
On Wed, Nov 01, 2006 at 02:09:30PM +1100, Benjamin Herrenschmidt wrote:
> The alignment exception used to only check the exception table for
> -EFAULT, not for other errors. That opens an oops window if we can
> coerce the kernel into getting an alignment exception for other reasons
> in what would normally be a user-protected accessor, which can be done
> via some of the futex ops. This fixes it by always checking the
> exception tables.
>
> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> ---
>
> This is 2.6.19 material and should probably go into stable as well.
> (Greg: take it if paulus acks it and it applies :)
Please forward the final patch (which ever version it is :) to the
stable@kernel.org address when this goes into mainline.
thanks,
greg k-h
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] powerpc: Make alignment exception always check exception table
2006-11-01 6:34 ` [PATCH] powerpc: Make alignment exception always check exception table Greg KH
@ 2006-11-01 20:43 ` Benjamin Herrenschmidt
0 siblings, 0 replies; 5+ messages in thread
From: Benjamin Herrenschmidt @ 2006-11-01 20:43 UTC (permalink / raw)
To: Greg KH; +Cc: linuxppc-dev list, Paul Mackerras
On Tue, 2006-10-31 at 22:34 -0800, Greg KH wrote:
> On Wed, Nov 01, 2006 at 02:09:30PM +1100, Benjamin Herrenschmidt wrote:
> > The alignment exception used to only check the exception table for
> > -EFAULT, not for other errors. That opens an oops window if we can
> > coerce the kernel into getting an alignment exception for other reasons
> > in what would normally be a user-protected accessor, which can be done
> > via some of the futex ops. This fixes it by always checking the
> > exception tables.
> >
> > Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> > ---
> >
> > This is 2.6.19 material and should probably go into stable as well.
> > (Greg: take it if paulus acks it and it applies :)
>
> Please forward the final patch (which ever version it is :) to the
> stable@kernel.org address when this goes into mainline.
Ok, will do. I wan't sure what the proper procedure was.
Cheers,
Ben.
^ permalink raw reply [flat|nested] 5+ messages in thread