Re: 4.15.17 regression: bisected: timeout during microcode update

[Vitezslav Samel <vitezslav@samel.cz>]

On Wed, Apr 18, 2018 at 06:53:30AM -0700, Raj, Ashok wrote:
> On Wed, Apr 18, 2018 at 02:22:12PM +0200, Borislav Petkov wrote:
> > On Wed, Apr 18, 2018 at 02:08:40PM +0200, Vitezslav Samel wrote:
> > > I switched to firmware-in-kernel early loading and that works OK.
> 
> firmware-in-kernel means you compile your microcode image in linux?

  Yes:

	CONFIG_FW_LOADER=y
	CONFIG_EXTRA_FIRMWARE="intel-ucode/06-3c-03"
	CONFIG_EXTRA_FIRMWARE_DIR="/lib/firmware"

> Can you tell me which distro you are using? The ones we used 
> doesn't do late-loading (i.e echo 1 > /sys/devices/system/cpu/microcode/reload)
> 
> I suspect that might be the problem. 

  Yes, this is it. I followed instructions included in current microcode
package downloaded from intel website and added "echo 1 > /sys/dev..."
to my Slackware's /etc/rc.d/rc.local.

> - Can you remove your builtin microcode, 
> - rename the /lib/firmware/intel-ucode so we don't find it during late loading. 
> - let the system boot completely
> - then rename the intel-ucode back for this test.
> - write 1 to reload and see if that update succeeds or fails?

  Just tested, it fails.

	Cheers,

		Vita

> > Ok, and keep using that from now on.
> > 
> > People should all move away from that late loading dance. I'm saying
> > that in case someone else reads this on lkml.
> > 
> > > But still, the reported issue is regression in 4.15.17 and 4.16+.
> > 
> > Oh, I know it is a regression.
> > 
> > @Ashok: anything particular about his microcode revision not being able
> > to stomach late loading?
> 
> nothing about the microcode itself comes to mind. I'm wondering if this 
> similar to the Arch linux that used late-load during booting might be an issue.