Hello, Bjorn. On Thu, Jan 24, 2013 at 10:45:13AM -0700, Bjorn Helgaas wrote: > On Fri, Dec 28, 2012 at 6:50 AM, Joonsoo Kim <js1...@gmail.com> wrote: > > During early boot phase, PCI bus subsystem is not yet initialized. > > If panic is occured in early boot phase and panic_timeout is set, > > code flow go into emergency_restart() and hit mach_reboot_fixups(), then > > encounter another panic. When second panic, we can't hold a panic_lock, so > > code flow go into panic_smp_self_stop() which prevent system to restart. > > > > For avoid second panic, skip reboot_fixups in early boot phase. > > It makes panic_timeout works in early boot phase. > > > > Cc: Thomas Gleixner <t...@linutronix.de> > > Cc: Ingo Molnar <mi...@redhat.com> > > Cc: "H. Peter Anvin" <h...@zytor.com> > > Signed-off-by: Joonsoo Kim <js1...@gmail.com> > > > > diff --git a/arch/x86/kernel/reboot_fixups_32.c > > b/arch/x86/kernel/reboot_fixups_32.c > > index c8e41e9..b9b8ec9 100644 > > --- a/arch/x86/kernel/reboot_fixups_32.c > > +++ b/arch/x86/kernel/reboot_fixups_32.c > > @@ -89,6 +89,10 @@ void mach_reboot_fixups(void) > > if (in_interrupt()) > > return; > > > > + /* During early boot phase, PCI is not yet initialized */ > > + if (system_state == SYSTEM_BOOTING) > > + return; > > + > > for (i=0; i < ARRAY_SIZE(fixups_table); i++) { > > cur = &(fixups_table[i]); > > dev = pci_get_device(cur->vendor, cur->device, NULL); > > I guess you're saying that if we call pci_get_device() too early, it > panics? Did you figure out why that happens? > > If we call pci_get_device() before PCI has been initialized, it would > be good if it just returned NULL, indicating that we didn't find any > matching device. I looked briefly, and I thought that's what would > happen, but apparently I'm missing something.
In bus_find_device(), klist_iter_init_node() is called with @bus->p->klist_device. Before initialization, bus->p is NULL, so panic is occured. > Bjorn > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majord...@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/