linux-kernel - Re: [PATCH] xtensa: improve stack dumping

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Message-ID: <CAMo8BfLmcCOAinyjB3iEuOF36TYBig=724=s9b6EKr3LzwF5QQ@mail.gmail.com>
Date:   Wed, 6 Nov 2019 16:21:51 -0800
From:   Max Filippov <jcmvbkbc@...il.com>
To:     Joe Perches <joe@...ches.com>
Cc:     "open list:TENSILICA XTENSA PORT (xtensa)" 
        <linux-xtensa@...ux-xtensa.org>, Chris Zankel <chris@...kel.net>,
        LKML <linux-kernel@...r.kernel.org>,
        Dmitry Safonov <dima@...sta.com>,
        Petr Mladek <pmladek@...e.com>
Subject: Re: [PATCH] xtensa: improve stack dumping

On Wed, Nov 6, 2019 at 2:34 PM Joe Perches <joe@...ches.com> wrote:
> > @@ -512,10 +510,12 @@ void show_stack(struct task_struct *task, unsigned long *sp)
> >       for (i = 0; i < kstack_depth_to_print; i++) {
> >               if (kstack_end(sp))
> >                       break;
> > -             pr_cont(" %08lx", *sp++);
> > +             sprintf(buf + (i % 8) * 9, " %08lx", *sp++);
> >               if (i % 8 == 7)
> > -                     pr_cont("\n");
> > +                     pr_info("%s\n", buf);
> >       }
> > +     if (i % 8)
> > +             pr_info("%s\n", buf);
>
> Could this be done using hex_dump_to_buffer
> by precalculating kstack_end ?

I've got this, but it doesn't look very attractive to me:

void show_stack(struct task_struct *task, unsigned long *sp)
{
        unsigned long *stack;
        int len;

        if (!sp)
                sp = stack_pointer(task);
        stack = sp;

        len = min((-(unsigned long)stack) & (THREAD_SIZE - 4),
                  kstack_depth_to_print * 4ul);

        pr_info("Stack:\n");

        for (; len > 0; len -= 32) {
                char buf[9 * 8 + 1];

                hex_dump_to_buffer(sp, min(len, 32), 32, 4,
                                   buf, sizeof(buf), false);
                pr_info(" %08lx:  %s\n", (unsigned long)sp, buf);
                sp += 8;
        }
        show_trace(task, stack);
}

-- 
Thanks.
-- Max