From: Jim Jagielski <jim@jaguNET.com>
Message-Id: <199812042332.SAA23318@devsys.jaguNET.com>
Subject: Re: Status bug FIX ??
To: new-httpd@apache.org
Date: Fri, 4 Dec 1998 18:32:04 -0500 (EST)
In-Reply-To: <Pine.LNX.3.96dg4.981204151404.30473j-100000@twinlark.arctic.org>
 from "Dean Gaudet" at Dec 4, 98 03:14:35 pm
Content-Type: text
Sender: new-httpd-owner@apache.org
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Reply-To: new-httpd@apache.org

Dean Gaudet wrote:
> 
> On Fri, 4 Dec 1998, Jim Jagielski wrote:
> 
> > Dean Gaudet wrote:
> > > 
> > > On Fri, 4 Dec 1998, Harrie Hazewinkel wrote:
> > > 
> > > > And since we only use the "server_hostname" of the server_rec
> > > > for "mod_status" I now use the "server_hostname" ptr directly
> > > > in the scoreboard.
> > > 
> > > That, too, breaks across restart.
> > > 
> > > Jim committed a fix which works in most cases, but still has a race
> > > condition.  The race condition is when a child is in the middle of serving
> > > a status request when a graceful restart happens, it will start reading
> > > server_rec's from children of the newer generation.
> > > 
> > 
> > Is that bad, ie: reading server_rec's from the _newer_ generation? At
> > least it's valid data. I had thought that the only problem was reading
> > server_rec info from the _previous_ generation, which would be bogus.
> > I admit that I hadn't considered the former...
> 
> Yup it's bad to read any pointer from another generation, newer or older,
> because the parent used to spawn the other child didn't have the same
> memory map.
> 

Gotcha. I had assumed that the memory would still be valid through
generations.

-- 
===========================================================================
   Jim Jagielski   |||   jim@jaguNET.com   |||   http://www.jaguNET.com/
            "That's no ordinary rabbit... that's the most foul,
            cruel and bad-tempered rodent you ever laid eyes on"