[PATCH 2/2] riscv: Fix __show_regs printing formats

[John Ogness]

On 2020-11-26, John Ogness <john.ogness at linutronix.de> wrote:
> On 2020-11-26, Kefeng Wang <wangkefeng.wang at huawei.com> wrote:
>> On 2020/11/26 6:58, Atish Patra wrote:
>>> On Tue, Nov 24, 2020 at 3:17 AM Kefeng Wang <wangkefeng.wang at huawei.com> wrote:
>>>> Using printk directly and align the printing formats.
>>>>
>>> Why switch to printk ? IIRC, pr_* is preferred over printk for any new code.
>>
>> The stack output is strange, that is why I move to printk, and the old
>> kernel looks good.
>
> This is just a quick response to let you know I can reproduce the issue
> and I am investigating.
>
> @Petr: The proposed change and output difference is here [0].

This is a bug in continuous line handling. I have posted [0] a fix to
LKML.

Note that a pr_cont() message with a trailing newline will "terminate"
the continous line so that it can no longer be continued. Having a bunch
of:

    pr_cont("...\n");

lines is technically wrong. If you really want the full block to be a
single message, put the newline at the beginning of the pr_cont()
message or add some whitespace after a newline at the end. For example:

    pr_cont("\n....");
       or
    pr_cont("...\n ");

Although I would suggest making them separate printk calls. With
CONFIG_PRINTK_CALLER it is still possible to sort out simultaneous dumps
from multiple CPUs.

Thank you for reporting this!

John Ogness

[0] https://lkml.kernel.org/r/20201126114836.14750-1-john.ogness@linutronix.de