linux-kernel - Re: Problem with wake_up using real-time scheduling

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: Windows password security audit tool. GUI, reports in PDF.

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

Message-ID: <4A4ABE06.1030907@gmail.com>
Date:	Tue, 30 Jun 2009 19:38:14 -0600
From:	Robert Hancock <hancockrwd@...il.com>
To:	Zoltan Bus <zoltan.bus@...il.com>
CC:	linux-kernel@...r.kernel.org
Subject: Re: Problem with wake_up using real-time scheduling

On 06/30/2009 02:44 AM, Zoltan Bus wrote:
> Hello,
>
> I have a problem on kernel 2.6.26.3. I have a real-time task which
> uses the select system call to poll my audio driver. The sleeping task
> is waken up by wake_up() from an interrupt handler.
> The problem is, that the wake_up() function  sometimes does not wake
> up the task if real-time priority is used.
>
> The try_to_wake_up() returns from the out_running section, because of the check
>
>        if (p->se.on_rq)
>                goto out_running;
>
> There are no other tasks running when the poll function is called.
>
> Is this a known problem? Is it fixed somehow in newer versions?
> Unfortunately I do not have the possibility to change the newest kernel version.
> I am a newbie at linux, thank you very much for your help.

Most likely there is something you're doing wrong in your driver, we 
would have to see the source code to give many useful suggestions..
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/