linuxsh-dev

Re: [linuxsh-dev] waitpid and 2.4.0 kernel

[Denis D. <dp...@al...>]

Hi Brian,

I put in about 2 days on this and have finally determined what is going on.
It seems the 2.4.0 kernel for the SH is starting up the init process with
SIG_CHLD set to SIG_IGN and not SIG_DFL. All child processes are getting
reaped by the init process rather than waiting around as zombies. This is
why pclose fails. 

The seems to be a 2.4.0 SH kernel problem but I could not find a way to fix
this. Instead I set SIG_CHLD to SIG_DFL in the busybox init program I am
using and all works correctly.

I suspect that this is fixed in the latest BusyBox release and broken in
0.48. Strange though?

Regards,
Denis.

----------
> From: Bryan Rittmeyer <br...@ix...>
> To: Denis Dowling <ddo...@po...>
> Cc: lin...@li...
> Subject: Re: [linuxsh-dev] waitpid and 2.4.0 kernel
> Date: Sunday, 14 January 2001 7:15
> 
> Denis Dowling wrote:
> 
> > I am trying to chace down a problem with popen() and pclose() using the
> > latest 2.4.0 kernel on the SuperH. I seems that waitpid is always
> > returning ECHILD even when the child process pid is correct and the
> > process has exited correctly. Is anyone else seeing this?
> 
> Yep. Interestingly enough, it shows up with the latest CVS version of
> BusyBox, but not with the 0.48 BusyBox release (or maybe vice versa, I
> don't remember exactly). I started noticing it after moving from -test10
> to 2.4.0, but I also changed binutils / gcc / glibc at the same time.
> Not precisely sure it's a kernel problem...
> 
> Regards,
> 
> Bryan
> 
> -- 
> Bryan Rittmeyer
> mailto:br...@ix...
> Ixia Communications
> 26601 W. Agoura Rd.
> Calabasas, CA 91302

Re: [linuxsh-dev] waitpid and 2.4.0 kernel

[Bryan R. <br...@ix...>]

Denis Dowling wrote:

> The seems to be a 2.4.0 SH kernel problem but I could not find a way to fix
> this. Instead I set SIG_CHLD to SIG_DFL in the busybox init program I am
> using and all works correctly.

Could you please supply me a patch for this?

> I suspect that this is fixed in the latest BusyBox release and broken in
> 0.48. Strange though?

Actually, I am still seeing this problem with 0.49pre BusyBox CVS and
2.4.0-pre2 LinuxSH CVS. For example:

[@(none) /]# mount -t ramfs ramfs mnt
mount: Mounting ramfs on mnt failed: No such device
sh: tcsetpgrp: Operation not permitted
sh: waitpid(56): No child processes
Process '/bin/busybox sh' (pid 11) exited.  Scheduling it for restart.

Please press Enter to activate this console. 


I don't think the "tcsetpgrp" complaint is related, but I did start
seeing it after moving up from 2.4.0-test10. Perhaps I need to upgrade
to glibc2.2?

Bryan

-- 
Bryan Rittmeyer
mailto:br...@ix...
Ixia Communications
26601 W. Agoura Rd.
Calabasas, CA 91302

Re: [linuxsh-dev] waitpid and 2.4.0 kernel

[Denis D. <ddo...@po...>]

Hi Brian,

I have attached the init patch for busybox. I am still using
busybox-0.47 but I suspect this patch will work with newer versions of
busybox. This patch makes init set the SIGCHLD handling to SIG_DFL. This
should not be needed but for some reason the 2.4.0 kernel is starting
the init process with SIGCHLD set to SIG_IGN.

Regards,
Denis.

PS: If you have the flash space I would replace busybox sh with a real
version of bash. It makes the target environment SO much more user
friendly.


Bryan Rittmeyer wrote:
> 
> Denis Dowling wrote:
> 
> > The seems to be a 2.4.0 SH kernel problem but I could not find a way to fix
> > this. Instead I set SIG_CHLD to SIG_DFL in the busybox init program I am
> > using and all works correctly.
> 
> Could you please supply me a patch for this?
> 
> > I suspect that this is fixed in the latest BusyBox release and broken in
> > 0.48. Strange though?
> 
> Actually, I am still seeing this problem with 0.49pre BusyBox CVS and
> 2.4.0-pre2 LinuxSH CVS. For example:
> 
> [@(none) /]# mount -t ramfs ramfs mnt
> mount: Mounting ramfs on mnt failed: No such device
> sh: tcsetpgrp: Operation not permitted
> sh: waitpid(56): No child processes
> Process '/bin/busybox sh' (pid 11) exited.  Scheduling it for restart.
> 
> Please press Enter to activate this console.
> 
> I don't think the "tcsetpgrp" complaint is related, but I did start
> seeing it after moving up from 2.4.0-test10. Perhaps I need to upgrade
> to glibc2.2?

Re: [linuxsh-dev] waitpid and 2.4.0 kernel

[Greg B. <gb...@po...>]

Denis Dowling wrote:
> 
> PS: If you have the flash space I would replace busybox sh with a real
> version of bash. It makes the target environment SO much more user
> friendly.

  Also, I found that the /etc/pcmcia scripts don't work at all
with busybox sh, they need a proper implementation of /bin/sh.

Greg.
-- 
These are my opinions not PPIs.