Re: [RFC PATCH v9 02/13] x86: always set IF before oopsing from page fault

[Andy Lutomirski <luto-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>]

On Wed, Apr 3, 2019 at 10:36 AM Khalid Aziz <khalid.aziz-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org> wrote:
>
> From: Tycho Andersen <tycho-E0fblnxP3wo@public.gmane.org>
>
> Oopsing might kill the task, via rewind_stack_do_exit() at the bottom, and
> that might sleep:
>


> diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
> index 9d5c75f02295..7891add0913f 100644
> --- a/arch/x86/mm/fault.c
> +++ b/arch/x86/mm/fault.c
> @@ -858,6 +858,12 @@ no_context(struct pt_regs *regs, unsigned long error_code,
>         /* Executive summary in case the body of the oops scrolled away */
>         printk(KERN_DEFAULT "CR2: %016lx\n", address);
>
> +       /*
> +        * We're about to oops, which might kill the task. Make sure we're
> +        * allowed to sleep.
> +        */
> +       flags |= X86_EFLAGS_IF;
> +
>         oops_end(flags, regs, sig);
>  }
>


NAK.  If there's a bug in rewind_stack_do_exit(), please fix it in
rewind_stack_do_exit().