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.
Bjorn
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