Date: Mon, 28 Oct 1996 10:53:27 +0100 (MET) From: Luigi Rizzo <luigi@labinfo.iet.unipi.it> To: dg@root.com Cc: csubl@csv.warwick.ac.uk, questions@FreeBSD.ORG Subject: Re: String space limit? Message-ID: <199610280953.KAA01270@labinfo.iet.unipi.it> In-Reply-To: <199610270648.XAA10943@root.com> from "David Greenman" at Oct 26, 96 11:47:59 pm
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>
> >I've been adding a lot of stuff to my X start up script, and I've strted
> > getting 'cat: No such process' errors, followed by '/kernel: execve: failed
> > to allocate string space'. The cat: errors are from a shell script called
> > several times at startup and occasionally later. The script seems to work
> > later on - I must be running out of some temporary resource, but my shell
> > limits all seem OK and I've set maxusers 30 (I'm not sure exactly how many
> > processes that is, but I've had over 100.)
> >
> >So what eactly am I running out of, and how can I get rid of the errors?
>
> You should always mention which version of FreeBSD the problem pertains
> to. The failure you're seeing is caused by more than 16 processes trying
> to exec simultaneously and running out of a kernel resource because of it.
> This failure case was eliminated in FreeBSD 2.1.5 (by adding code to block
> the process until the resource becomes available), so I would guess that
> you're using FreeBSD 2.1.0 or earlier.
I have to fix this on a system, and cannot upgrade to 2.1.5R.
I have looked at the diffs between 1.21.4.1 (2.1R) and 1.21.4.6 (I
believe it is 2.1.5R). Looks like much of the difference comes from
a renaming of variables; other than that, the code looks simpler.
Since I am not too familiar with kernel functions, would the
following work ?
--- src/sys/kern/kern_exec.c 1995/08/31 10:00:43 1.21.4.1
+++ src/sys/kern/kern_exec.c 1996/06/04 02:11:37 1.21.4.6
/*
* Allocate temporary demand zeroed space for argument and
* environment strings
*/
- iparams->stringbase = (char *)vm_map_min(exec_map);
- error = vm_map_find(exec_map, NULL, 0, (vm_offset_t *)&iparams->stringbase,
- ARG_MAX, TRUE);
- if (error) {
- log(LOG_WARNING, "execve: failed to allocate string space\n");
- return (error);
- }
-
+ iparams->stringbase = (char *)kmem_alloc_wait(exec_map, ARG_MAX);
if (!iparams->stringbase) {
error = ENOMEM;
goto exec_fail;
}
Thanks
Luigi
====================================================================
Luigi Rizzo Dip. di Ingegneria dell'Informazione
email: luigi@iet.unipi.it Universita' di Pisa
tel: +39-50-568533 via Diotisalvi 2, 56126 PISA (Italy)
fax: +39-50-568522 http://www.iet.unipi.it/~luigi/
====================================================================
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