Re: [PATCH 0/3][RESEND] add support for never printing hashed addresses

Tetsuo Handa
2021-02-10T17:42:54Z

On 2021/02/11 1:54, Andy Shevchenko wrote:
> On Thu, Feb 11, 2021 at 01:39:41AM +0900, Tetsuo Handa wrote:
>> On 2021/02/11 1:18, Steven Rostedt wrote:
>>> The point of this exercise is to be able to debug the *same* kernel that
>>> someone is having issues with. And this is to facilitate that debugging.
>>
>> That's too difficult to use. If a problem is not reproducible, we will have
>> no choice but always specify "never hash pointers" command line option. If a
>> problem is reproducible, we can rebuild that kernel with "never hash pointers"
>> config option turned on.
>
> I think what you are targeting is something like dynamic debug approach where
> you can choose which prints to enable/disable and what enable/disable in them.

What I'm targeting is "zero interaction from kernel command line options" like
https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/drivers/usb/usbip?id=f1bdf414e7dd0cbc26460425719fc3ea479947a2 .

>
> In that case you specifically apply a command line option and enable only files
> / lines in the files.

While there is boot-config feature for specifying very long kernel command line
options, I can't enforce syzkaller users (including syzbot) to switch what to
enable/disable via kernel command line options. Let alone defining a kernel
command line option for single-purpose debug printk() changes like shown above.