David, it is possible that ksh93 has similar issues? I noticed that
even in ast-ksh.20130611 ksh93's job handling does not make use of the
siginfo data provided with the CHLD signal and polls the child process
list instead.

Ced

---------- Forwarded message ----------
From: Chet Ramey <[email protected]>
Date: 24 May 2013 16:00
Subject: Re: deadlock in waitchld()
To: Roman Rakus <[email protected]>
Cc: [email protected], [email protected]


On 5/24/13 9:30 AM, Roman Rakus wrote:
> The race is in do-while loop in wait_for(). At the start of wait_for() we
> are blocking SIGCHLD, however echo process ends during the loop and we
> don't register it (don't handle SIGCHLD, which is sent).
> Looking at the code, there is MUST_UNBLOCK_CHLD. May it make any harm to
> enable it by default?

I spent a lot of time looking at this yesterday, and I have it pretty much
fixed.  The problem is in the trap handling code, not wait_for().  The trap
problem ends up corrupting the jobs data structure, which is why wait_for
misbehaves.

Chet

--
``The lyf so short, the craft so long to lerne.'' - Chaucer
                 ``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, ITS, CWRU    [email protected]    http://cnswww.cns.cwru.edu/~chet/



-- 
Cedric Blancher <[email protected]>
Institute Pasteur
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