freebsd-5.4-stable panics

[Antoine Pelisse]

On 9/30/05, John Baldwin <jhb at freebsd.org> wrote:
>
> On Friday 30 September 2005 11:25 am, Antoine Pelisse wrote:
> > On 9/30/05, John Baldwin <jhb at freebsd.org> wrote:
> > > On Friday 30 September 2005 05:24 am, Antoine Pelisse wrote:
> > > > Hi Robert,
> > > > I don't think your patch is correct, the total linked list can be
> > > > broken
> > > >
> > > > while the lock is released, thus just passing the link may not be
> > > > enough I have submitted a PR[1] for this a month ago but nobody took
> > > > care of it yet Regards,
> > > > Antoine Pelisse
> > > >
> > > > [1] http://www.freebsd.org/cgi/query-pr.cgi?pr=kern/84684
> > >
> > > I think this patch looks ok. Robert, can you get the original panic on
> > > this
> > > thread tested against this patch?
> >
> > I had a small program which could reproduce this panic in 10 seconds, it
> > was basically creating empty threads and calling kvm_getprocs() in the
> same
> > time. Anyway the patch was able to stop the program from panicing.
> > The panic is also reproducible in RELENG_6 and HEAD IIRC.
>
> It turns out that the sysctl buffer is already wired in one of the two
> cases
> that this function is called, so I moved the wiring up to the upper layer
> in
> the other case and cut out a bunch of the locking gymnastics as a result.
> Can you try this patch?
>
> Index: kern_proc.c
> ===================================================================
> RCS file: /usr/cvs/src/sys/kern/kern_proc.c,v
> retrieving revision 1.231
> diff -u -r1.231 kern_proc.c
> --- kern_proc.c 27 Sep 2005 18:03:15 -0000 1.231
> +++ kern_proc.c 30 Sep 2005 17:04:57 -0000
> @@ -875,22 +875,16 @@
>
> if (flags & KERN_PROC_NOTHREADS) {
> fill_kinfo_proc(p, &kinfo_proc);
> - PROC_UNLOCK(p);
> error = SYSCTL_OUT(req, (caddr_t)&kinfo_proc,
> sizeof(kinfo_proc));
> - PROC_LOCK(p);
> } else {
> - _PHOLD(p);
> FOREACH_THREAD_IN_PROC(p, td) {
> fill_kinfo_thread(td, &kinfo_proc);
> - PROC_UNLOCK(p);
> error = SYSCTL_OUT(req, (caddr_t)&kinfo_proc,
> sizeof(kinfo_proc));
> - PROC_LOCK(p);
> if (error)
> break;
> }
> - _PRELE(p);
> }
> PROC_UNLOCK(p);
> if (error)
> @@ -932,6 +926,9 @@
> if (oid_number == KERN_PROC_PID) {
> if (namelen != 1)
> return (EINVAL);
> + error = sysctl_wire_old_buffer(req, 0);
> + if (error)
> + return (error);
> p = pfind((pid_t)name[0]);
> if (!p)
> return (ESRCH);
>
> --
> John Baldwin <jhb at FreeBSD.org> <>< http://www.FreeBSD.org/~jhb/
> "Power Users Use the Power to Serve" = http://www.FreeBSD.org
>
 Hi John,
 I'm sorry I can't test it right now, I'm in a foreign country for three
months and can only connect to the internet through the university
connection.
I'll be back home mid-december. Maybe Rob should take care of testing it.
 Regards,
Antoine Pelisse