lkml.org 
[lkml]   [2007]   [Mar]   [1]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: + fully-honor-vdso_enabled.patch added to -mm tree
John Reiser 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.

Note also that load_elf_binary does

arch_setup_additional_pages()
create_elf_tables()

, looks like application can crash after exec if vdso_enabled changes from 0
to 1 in between.

Could you please explain if I missed something?

Oleg.

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2007-03-01 18:53    [W:0.181 / U:0.244 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site