Kernel thread in a driver: Unable to wake up thread if I quit the dev file and reopen it.

[Stephane Cerveau]

Hi all,

I found finally which CONFIG is involved in my problem. It was
CONFIG_ASH_JOB_CONTROL which need to be set.
Now my kernel driver can be add and removed and when I quit my app I can
relaunch it. My kernel thread is correctly awaken.
But I don't know why... I don't understand why this CONFIG is involved
in this use case.
IF someone knows why, I would be grateful to be informed ;)
Cheers.

Steph
 

-----Original Message-----
From: Denys Vlasenko [mailto:vda.linux at googlemail.com] 
Sent: Thursday, September 13, 2007 8:09 PM
To: busybox at busybox.net
Cc: Stephane Cerveau
Subject: Re: Kernel thread in a driver: Unable to wake up thread if I
quit the dev file and reopen it.

On Thursday 13 September 2007 17:28, Stephane Cerveau wrote:
> Hi,
>  
> I'm using busybox 1.1.0 and encounter a problem with a kernel thread 
> in a char driver.
> I have a char driver using a kernel thread awaken(it reads data in a
> registry) when it receive an interrupt signal.
> When I insert the driver (insmod) and read data in the dev file 
> (/dev/toto:name of my device), it's working well.
> But when i close the dev (quit my app) and relaunch my app. My driver 
> still receives interrupt but the kernel thread cant be awaken.
>  
> The reason I ask this question in busybox mailing list is that it 
> seems to depend on busybox config. Indeed I have another busybox 
> binary
> (1.1.3) where all is working fine. So I tried to update my busybox 
> 1.1.0 to 1.1.3 keeping my old config(I have to keep it) and its also 
> not working.
> So I would like to know if anyone know a config item in busybox which 
> can interfer with kernel thread or anything close to my problem.
> Any answer is welcome :p

Can you provide e.g. a strace of old and new programs, with new program
exhibitions a problem? (use -tt option to strace too).
--
vda