Re: [PATCH] kprobes: Introduce is_kprobe_fault()

From: Harvey Harrison
Date: Thu Jan 03 2008 - 12:37:20 EST


On Thu, 2008-01-03 at 12:35 +0530, Ananth N Mavinakayanahalli wrote:
> On Wed, Jan 02, 2008 at 08:05:14PM -0800, Harvey Harrison wrote:
>
> Thanks for the cleanup...
>
> ...
>
> > diff --git a/arch/x86/mm/fault_32.c b/arch/x86/mm/fault_32.c
> > index a2273d4..f2e909b 100644
> > --- a/arch/x86/mm/fault_32.c
> > +++ b/arch/x86/mm/fault_32.c
> > @@ -33,28 +33,6 @@
> >
> > extern void die(const char *,struct pt_regs *,long);
> >
> > -#ifdef CONFIG_KPROBES
> > -static inline int notify_page_fault(struct pt_regs *regs)
> > -{
> > - int ret = 0;
> > -
> > - /* kprobe_running() needs smp_processor_id() */
> > - if (!user_mode_vm(regs)) {
> ^^^^^^^^^^^
> For x86_32, this check is important. See commit
> 6444541671bd821b950dbaafee70d65188198aa6 (Never allow int3 traps
> from V8086 mode to enter the kprobes handler) for precise reason why its
> user_mode_vm() and not user_mode() for x86_32.
>
> You'll need to make room for this check in the generic macro below...

Or just keep X86_32 using its existing notify_page_fault, everyone else
can use the new is_kprobe_fault. I'll wait for a bit and see if
the s390 or avr32 people respond before resending.

Harvey



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