Date: Wed, 09 Jun 2004 04:21:38 -0700 From: Sean McNeil <sean@mcneil.com> To: Marcel Moolenaar <marcel@xcllnt.net> Cc: Daniel Eischen <eischen@vigrid.com> Subject: Re: All my amd64 problems appear to be KSE Message-ID: <1086780098.95500.4.camel@server.mcneil.com> In-Reply-To: <20040605194113.GA26707@dhcp50.pn.xcllnt.net> References: <1086458607.18813.37.camel@server.mcneil.com> <Pine.GSO.4.10.10406051518530.29855-100000@pcnet5.pcnet.com> <20040605194113.GA26707@dhcp50.pn.xcllnt.net>
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On Sat, 2004-06-05 at 12:41, Marcel Moolenaar wrote: > On Sat, Jun 05, 2004 at 03:21:29PM -0400, Daniel Eischen wrote: > > > > > > I suppose it is really libreadline at fault here and it should check > > > SA_SIGINFO. Do you think there might be others that don't check either? > > > > I don't know; perhaps. > > > > > Why doesn't this show an issue in i386? Is it just luck that info has > > > been null and not caused a bad dereference? > > > > When I write signal handlers, I usually check info and ucp to > > make sure they are not null before using them. Actually, I > > rarely use them anyways so it doesn't matter if they are null > > or not. > > Nevertheless, libpthread has a signal handler that takes 3 arguments > and it apparently gets called from other signal handlers (chaining) > that do not always pass along the full context; just the signal number > in this case. Consequently, info and ucp can be garbage as is the case > here. This is a general problem and potentionally causes failures on > all platforms, not just amd64. > > I tend to give blame to libreadline here, but I don't have a clear or > even complete picture of it all, so I might actually miss a vital > precondition that's being violated and that would clear libreadline... This really isn't libreadline's fault, but it is an issue. They should check to see if the signal hander/action has SA_SIGINFO. The problem I saw should never have happened. It came about because of a symbol binding issue. Removing an incorrect usage of libpthread by libdb41 resolved the issue. In the long run, it would be nice to fix this as there may be a time when someone installs an SA_SIGINFO handler before libreadline is initialized. Cheers, Sean
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