loader crash / BTX halted on 9.0-RC2 DVD with AMD pseudo-RAID
lists at jnielsen.net
Wed Nov 23 03:18:57 UTC 2011
On Nov 22, 2011, at 10:26 AM, John Baldwin <jhb at freebsd.org> wrote:
> On Monday, November 21, 2011 1:45:36 pm John Nielsen wrote:
>> This weekend I downloaded the Freebsd 9.0 RC2 amd64 ISO image and burned it
> to a DVD. I have a computer that currently runs Windows 7 but I plan to
> install FreeBSD on it in the near future so I booted it up from the DVD to
> check the hardware/driver status. Much to my dismay, the boot loader crashed
> right away (register dump followed by "BTX halted") and the computer
> immediately rebooted. I took a video with my phone so I could capture the
> crash message, screenshot here:
>> I then tried tweaking a few BIOS settings and found that turning off the
> built-in pseudo-RAID allowed the DVD to boot normally. I changed the SATA type
> from "RAID" to "AHCI". Fortunately I plan to use the controller in AHCI mode
> for the FreeBSD installation so this won't end up being a problem for me, but
> I still thought it was worth reporting.
> Hmmm, so this is odd. It died with an Invalid TSS exception on the iret
> instruction at the end of the return-from-real-mode trampoline in BTX.
> Looking at the dump I noticed that PSL_NT is set in %eflags, so for some
> reason the iret was trying to do a nested task return. We shouldn't let
> that flag leak out of any real mode code. Try this patch perhaps:
Thanks for looking!
I put gptboot on a USB stick and tried it with and without the patch. Identical behavior in both cases to booting from the DVD (only faster)--BTX dump and an instant reboot. I didn't do a screen capture yet but will be happy to tomorrow if it will help.
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