On Thu, Mar 01, 2007 at 08:52:07PM +0300, Oleg Nesterov wrote:
> > --- a/arch/i386/kernel/sysenter.c~fully-honor-vdso_enabled
> > +++ a/arch/i386/kernel/sysenter.c
> > @@ -22,6 +22,8 @@
> > #include <asm/msr.h>
> > #include <asm/pgtable.h>
> > #include <asm/unistd.h>
> > +#include <asm/a.out.h>
> > +#include <asm/mman.h>
> >
> > /*
> > * Should the kernel map a VDSO page into processes and pass its
> > @@ -105,10 +107,25 @@ int arch_setup_additional_pages(struct l
> > {
> > struct mm_struct *mm = current->mm;
> > unsigned long addr;
> > + unsigned long flags;
> > int ret;
> >
> > + switch (vdso_enabled) {
> > + case 0: /* none */
> > + return 0;
>
> This means we don't initialize mm->context.vdso and ->sysenter_return.
>
> Is it ok? For example, setup_rt_frame() uses VDSO_SYM(&__kernel_rt_sigreturn),
> sysenter_past_esp pushes ->sysenter_return on stack.
>
The setup_rt_frame() case is fairly straightforward, both PPC and SH
already check to make sure there's a valid context before trying to use
VDSO_SYM(), I'm not sure why x86 doesn't.
Though I wonder if there's any point in checking binfmt->hasvdso here?
There shouldn't be a valid mm->context.vdso in the !hasvdso case..
Someone else will have to comment on ->sysenter_return.
Signed-off-by: Paul Mundt <[EMAIL PROTECTED]>
--
arch/i386/kernel/signal.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/i386/kernel/signal.c b/arch/i386/kernel/signal.c
index 4f99e87..f778d34 100644
--- a/arch/i386/kernel/signal.c
+++ b/arch/i386/kernel/signal.c
@@ -350,7 +350,7 @@ static int setup_frame(int sig, struct k_sigaction *ka,
goto give_sigsegv;
}
- if (current->binfmt->hasvdso)
+ if (current->binfmt->hasvdso && current->mm->context.vdso)
restorer = (void *)VDSO_SYM(&__kernel_sigreturn);
else
restorer = (void *)&frame->retcode;
-
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