Re: [PATCH 4/7] x86/dumpstack: If addr_limit is non-default, display it

From: Borislav Petkov
Date: Wed May 25 2016 - 07:39:35 EST


On Tue, May 24, 2016 at 03:48:41PM -0700, Andy Lutomirski wrote:
> This will help debug OOPSes related to USER_DS vs KERNEL_DS.
>
> Signed-off-by: Andy Lutomirski <luto@xxxxxxxxxx>
> ---
> arch/x86/kernel/dumpstack_32.c | 4 ++++
> arch/x86/kernel/dumpstack_64.c | 5 +++++
> 2 files changed, 9 insertions(+)
>
> diff --git a/arch/x86/kernel/dumpstack_32.c b/arch/x86/kernel/dumpstack_32.c
> index 464ffd69b92e..5dbb08fd8291 100644
> --- a/arch/x86/kernel/dumpstack_32.c
> +++ b/arch/x86/kernel/dumpstack_32.c
> @@ -124,8 +124,12 @@ show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs,
> void show_regs(struct pt_regs *regs)
> {
> int i;
> + struct thread_info *ti = current_thread_info();
>
> show_regs_print_info(KERN_EMERG);
> + if (ti->addr_limit.seg != TASK_SIZE_MAX)
> + printk(KERN_DEFAULT "task.addr_limit: 0x%lx\n",
> + ti->addr_limit.seg);

And, of course, that printk should be part of the printk in
show_regs_print_info() and not duplicated here and in dumpstack_64.c

--
Regards/Gruss,
Boris.

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