Re: zsh 3.0.7 hogs memory

[James Kirkpatrick <jimkirk@uwyo.edu>]

Bart,

Of the three suggestions (attach dbx, add a TRAPHUP, recompile with patch)
I tried the TRAPHUP and that does indeed seem to solve the problem.
However, it seems more of an experiment than a true fix.

Does this give you enough to work towards a proper fix, or should I do
more to characterize the problem (e.g. try one of the other two
suggestions)?

Jim

On Wed, 24 Nov 1999, Bart Schaefer wrote:

> On Nov 23,  3:17pm, James Kirkpatrick wrote:
> } Subject: zsh 3.0.7 hogs memory
> }
> } It usually seems to happen to people running Pine (4.10).  My guess at
> } this point is that they dial in, start pine, and then either disconnect or
> } become disconnected.
> } 
> } One other clue:  This only started happening when I added the following to
> } /etc/zshenv:
> } 
> }   export HISTSIZE=200
> }   export HISTFILE=~/.zsh_history
> }   export SAVEHIST=200
> } 
> } Once I commented it out, the problem went away.  SO, I'm suspicious of
> } problems in exception handling (disconnect) with history files turned on.
> 
> (I'm going to assume that by "exceptions" you mean "signals".)
> 
> The relevant bits of code would be:
> 
> 	signals.c: 464: handler()
> 	builtin.c: 4761: zexit()
> 	hist.c: 1502-1584: savehistfile()
> and maybe
> 	signals.c: 543: killrunjobs()
> 
> The only thing I could guess that might be happening is:
> 
> handler(), invoked on SIGHUP, calls zexit(), which calls killrunjobs();
> killrunjobs() finds a job with group leader the current shell, and sends
> it a SIGHUP; this invokes handler() again, and we loop.
> 
> Now, it *should* be the case that during the handling of a SIGHUP, any
> additional SIGHUP is blocked.  The only possible connection I can come
> up with between this and savehistfile() is if the stdio operations that
> savehistfile() is using are somehow unblocking the signal, which seems
> *very* unlikely.
> 
> You could attach dbx or gdb to one of the runaway processes (the smallest
> one) and get a look at the stack.  Or (less helpful) you could try trapping
> the HUP signal by adding this to /etc/zshenv as well:
> 
> 	TRAPHUP() { exit 1 }
> 
> This will invoke zexit() in a slightly different way ("from_signal" will
> be false) and should avoid the SIGHUP loop I described, if in fact that
> is the problem.
> 
> Or you could assume that's the problem and try this patch:
> 
> Index: Src/signals.c
> ===================================================================
> @@ -540,7 +540,8 @@
>          if ((from_signal || i != thisjob) && (jobtab[i].stat & STAT_LOCKED) &&
>              !(jobtab[i].stat & STAT_NOPRINT) &&
>              !(jobtab[i].stat & STAT_STOPPED)) {
> -            if (killpg(jobtab[i].gleader, SIGHUP) != -1)
> +            if (jobtab[i].gleader != getpid() &&
> +		killpg(jobtab[i].gleader, SIGHUP) != -1)
>                  killed++;
>          }
>      if (killed)
> 
> I'll be a bit concerned about other signal-handling issues if that really
> does fix it, though.
> 
> -- 
> Bart Schaefer                                 Brass Lantern Enterprises
> http://www.well.com/user/barts              http://www.brasslantern.com