On Tue, 16 Nov 2021, Jan Beulich wrote:
> On 15.11.2021 23:27, Stefano Stabellini wrote:
> > From: Stefano Stabellini <stefano.stabellini@xxxxxxxxxx>
> >
> > In case of errors in xenbus_init (e.g. missing xen_store_gfn parameter),
> > we goto out_error but we forget to reset xen_store_domain_type to
> > XS_UNKNOWN. As a consequence xenbus_probe_initcall and other initcalls
> > will still try to initialize xenstore resulting into a crash at boot.
> >
> > [ 2.479830] Call trace:
> > [ 2.482314] xb_init_comms+0x18/0x150
> > [ 2.486354] xs_init+0x34/0x138
> > [ 2.489786] xenbus_probe+0x4c/0x70
> > [ 2.498432] xenbus_probe_initcall+0x2c/0x7c
> > [ 2.503944] do_one_initcall+0x54/0x1b8
> > [ 2.507358] kernel_init_freeable+0x1ac/0x210
> > [ 2.511617] kernel_init+0x28/0x130
> > [ 2.516112] ret_from_fork+0x10/0x20
> >
> > Cc: <Stable@xxxxxxxxxxxxxxx>
> > Cc: jbeulich@xxxxxxxx
> > Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxx>
>
> For the immediate purpose as described this looks okay, so
> Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>
Thank you!
> However, aren't there further pieces missing on this error patch:
> - clearing of xenstored_ready in case it got set,
> - rolling back xenstored_local_init() (XS_LOCAL) and xen_remap()
> (XS_HVM).
> And shouldn't xs_init() failure when called from xenbus_probe()
> also result in the driver not giving the appearance of being usable?
I prioritized this patch because I have a direct test case for this
issue and I can see that this patch solves it. But what you wrote is
true, and I can have a look in the following weeks.
> > --- a/drivers/xen/xenbus/xenbus_probe.c
> > +++ b/drivers/xen/xenbus/xenbus_probe.c
> > @@ -909,7 +909,7 @@ static struct notifier_block xenbus_resume_nb = {
> >
> > static int __init xenbus_init(void)
> > {
> > - int err = 0;
> > + int err;
> > uint64_t v = 0;
> > xen_store_domain_type = XS_UNKNOWN;
> >
>
> Minor remark: You may want to take the opportunity and add the
> missing blank line here to visually separate the assignment from
> the declarations.
>
> Jan
>
