2005-09-08 16:38:41

by Tom Rini

Subject: [PATCH 2.6.13] x86_64: Add notify_die() to another spot in do_page_fault()

This adds a call to notify_die() in the "no context" portion of
do_page_fault() as someone on the chain might care and want to do a fixup.

---

linux-2.6.13-trini/arch/x86_64/mm/fault.c | 4 ++++
1 files changed, 4 insertions(+)

diff -puN arch/x86_64/mm/fault.c~x86_64-no_context_hook arch/x86_64/mm/fault.c
--- linux-2.6.13/arch/x86_64/mm/fault.c~x86_64-no_context_hook 2005-09-01 12:00:43.000000000 -0700
+++ linux-2.6.13-trini/arch/x86_64/mm/fault.c 2005-09-01 12:00:43.000000000 -0700
@@ -514,6 +514,10 @@ no_context:
if (is_errata93(regs, address))
return;

+ if (notify_die(DIE_PAGE_FAULT, "no context", regs, error_code, 14,
+ SIGSEGV) == NOTIFY_STOP)
+ return;
+
/*
* Oops. The kernel tried to access some bad page. We'll have to
* terminate things with extreme prejudice.

--
Tom Rini
http://gate.crashing.org/~trini/

2005-09-09 08:01:07

by Andi Kleen

Subject: Re: [PATCH 2.6.13] x86_64: Add notify_die() to another spot in do_page_fault()

On Thursday 08 September 2005 18:38, Tom Rini wrote:
> This adds a call to notify_die() in the "no context" portion of
> do_page_fault() as someone on the chain might care and want to do a fixup.
>
> ---
>
> linux-2.6.13-trini/arch/x86_64/mm/fault.c | 4 ++++
> 1 files changed, 4 insertions(+)
>
> diff -puN arch/x86_64/mm/fault.c~x86_64-no_context_hook
> arch/x86_64/mm/fault.c ---
> linux-2.6.13/arch/x86_64/mm/fault.c~x86_64-no_context_hook 2005-09-01
> 12:00:43.000000000 -0700 +++
> linux-2.6.13-trini/arch/x86_64/mm/fault.c 2005-09-01 12:00:43.000000000
> -0700 @@ -514,6 +514,10 @@ no_context:
> if (is_errata93(regs, address))
> return;
>
> + if (notify_die(DIE_PAGE_FAULT, "no context", regs, error_code, 14,
> + SIGSEGV) == NOTIFY_STOP)
> + return;
> +

But how would the chain users distingush this from the DIE_PAGE_FAULT
reported at the beginning of the page fault handler? I don't see how
it can work. If anything you would need a DIE_NO_CONTEXT or somesuch, no?

-Andi

2005-09-09 12:47:13

by Tom Rini

Subject: Re: [PATCH 2.6.13] x86_64: Add notify_die() to another spot in do_page_fault()

On Fri, Sep 09, 2005 at 10:01:00AM +0200, Andi Kleen wrote:
> On Thursday 08 September 2005 18:38, Tom Rini wrote:
> > This adds a call to notify_die() in the "no context" portion of
> > do_page_fault() as someone on the chain might care and want to do a fixup.
> >
> > ---
> >
> > linux-2.6.13-trini/arch/x86_64/mm/fault.c | 4 ++++
> > 1 files changed, 4 insertions(+)
> >
> > diff -puN arch/x86_64/mm/fault.c~x86_64-no_context_hook
> > arch/x86_64/mm/fault.c ---
> > linux-2.6.13/arch/x86_64/mm/fault.c~x86_64-no_context_hook 2005-09-01
> > 12:00:43.000000000 -0700 +++
> > linux-2.6.13-trini/arch/x86_64/mm/fault.c 2005-09-01 12:00:43.000000000
> > -0700 @@ -514,6 +514,10 @@ no_context:
> > if (is_errata93(regs, address))
> > return;
> >
> > + if (notify_die(DIE_PAGE_FAULT, "no context", regs, error_code, 14,
> > + SIGSEGV) == NOTIFY_STOP)
> > + return;
> > +
>
> But how would the chain users distingush this from the DIE_PAGE_FAULT
> reported at the beginning of the page fault handler? I don't see how
> it can work. If anything you would need a DIE_NO_CONTEXT or somesuch, no?

"no context" is passed to the functions as well, and in KGDB we strcmp
on that.

--
Tom Rini
http://gate.crashing.org/~trini/

2005-09-09 12:52:52

by Andi Kleen

Subject: Re: [PATCH 2.6.13] x86_64: Add notify_die() to another spot in do_page_fault()

On Friday 09 September 2005 14:47, Tom Rini wrote:

> "no context" is passed to the functions as well, and in KGDB we strcmp
> on that.

Please define a new DIE code instead.

-Andi