linux-kernel - Re: [PATCH v2] scheduler: enhancement to show_state

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Tue, 8 Aug 2017 18:36:41 +0800
From:   Yafang Shao <laoar.shao@...il.com>
To:     Peter Zijlstra <peterz@...radead.org>
Cc:     gregkh@...uxfoundation.org, jslaby@...e.com, mingo@...hat.com,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] scheduler: enhancement to show_state_filter

Hi Peter,

In oder to make it readable, I have comment in the patch why this
change is made,
    -               if (!state_filter || (p->state & state_filter))
    +               /* in case we want to set TASK_RUNNING specifically */
    +               if ((p->state != TASK_RUNNING ? p->state << 1 : 1)
& state_filter)
                            sched_show_task(p);

show_state_filter() is only used in SysRq,  in which we can dump all
tasks (with the key 't'), or uninterruptible tasks(with the key 'w').
I think we should also dump only running tasks (with a new key, or
something else).
But in order to introduce the new key, we should made this change first.

After this change got approved, I will try to make some changes in SysRq.

Thanks
Yafang


2017-08-08 18:24 GMT+08:00 Peter Zijlstra <peterz@...radead.org>:
> On Tue, Aug 08, 2017 at 04:50:23PM +0800, Yafang Shao wrote:
>> Hi Peter,
>>
>> The point is we call use it as bellow,
>>     show_state_filter(TASK_RUNNING);
>> because TASK_RUNNING is 0, that will dump all tasks.
>>
>> Under some circumstance, we need this to dump only tasks in TASK_RUNNING state.
>
> But the patch doesn't introduce any of that. It just makes the existing
> code unreadable.