Re: [GIT pull] CPU hotplug updates for 4.9

[Thomas Gleixner]

Bart,

On Wed, 8 Mar 2017, Bart Van Assche wrote:

> Sorry but the cpuhp_issue_call() still occurs with Linus' latest tree
> (commit ec3b93ae0bf4 / Merge branch 'x86-urgent-for-linus' of
> git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip).
> 
> This morning I discovered that the hang only occurs if I/O AT support is
> enabled in the BIOS. I had enabled I/O AT support in the BIOS on February
> 23rd. With I/O AT support enabled the following warning appears during boot:

That's interesting, but I have no idea how that's related.

> WARNING: CPU: 8 PID: 596 at drivers/dma/ioat/dca.c:342 ioat_dca_init+0x185/0x190 [ioatdma]
> ioatdma 0000:00:04.0: APICID_TAG_MAP set incorrectly by BIOS, disabling DCA

..

> In contrast with previous tests this morning I have been able to reproduce
> this hang with kernel v4.10. So it's not a kernel v4.10 regression. But the
> hang did not occur in a test with kernel v4.9.7. I assume this means that
> the regression got introduced between the v4.9 and v4.10 kernels.

Is it always the x86_pkg_thermal init which locks up?

Thanks,

	tglx