Re: [PATCH 8/8] x86: I/O APIC: Timer through 8259A second-chance

From: Cyrill Gorcunov
Date: Thu Jun 05 2008 - 14:52:53 EST


[Maciej W. Rozycki - Thu, Jun 05, 2008 at 07:33:04PM +0100]
| On Thu, 5 Jun 2008, Ingo Molnar wrote:
|
| > NOTE: you need to copy out and use the boot parameters from the boot
| > log:
| >
| > [ 0.000000] Command line: root=/dev/sda6 console=ttyS0,115200
| > earlyprintk=se rial,ttyS0,115200 debug initcall_debug apic=verbose
| > sysrq_always_enabled ignore _loglevel selinux=0 nmi_watchdog=1
| > profile=0 maxcpus=1 nosmp no_hz=off highres =0 noapic nolapic_timer
| > hpet=disable idle=mwait
| >
| > as -tip testing occasionally randomizes boot parameters too. (to find
| > regressions like this) Let me know if you cannot reproduce this.
|
| Thanks. I figured out I cannot build an x86-64 kernel, because my i386
| compiler does not support the target. Probably because of target library
| dependencies at the time I built my compiler. I would have to build a
| bare-iron cross-compiler for the x86-64 which I'd rather not to just to
| fix this small problem -- it usually takes a few days to sort out all the
| pesky details when doing such a build from scratch, so it better be well
| justified.
|
| However, the reason is quite clear to me -- the command line specifies
| "noapic" among others (there is also "nosmp", but probably overridden by
| "maxcpus=1" -- I am afraid there is no clear precedence among these
| options), so the bug is the I/O APIC NMI watchdog is tried at all. This
| is also clearly seen from the log where the I/O APIC is not set up at all.
|
| A fix along the lines of what I implemented for "nosmp" in the
| "nosmp-watchdog" patch is needed which I will post shortly. It's needed
| both for the i386 and the x86-64 target; hopefully the latter does not
| differ too much from the former.
|
| Maciej
|

Since I've got the same hang by using qemu - i think i could test ;)

- Cyrill -
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