Subject: Re: [PATCH] Correct cpu affinity for dlpar added cpus

From: Michael Ellerman <[email-masked]>
Date: Wed, 29 Apr 2015 14:53:27 +1000

Subject should be "powerpc/pseries: ..." please.

On Tue, 2015-04-28 at 10:37 -0500, Nathan Fontenot wrote:
> The incorrect ordering of operations during cpu dlpar causes the affinity
> of cpus being added to be invalid. Phyp does not assign affinity information
> for a cpu until the rtas set-indicator calls are made to set the isolation
> and allocation state. In the current code we call rtas configure-connector
> before making the set-indicator calls which results in invalid data in the
> ibm,associativity property for the cpu we're adding.

Invalid and benign? Or invalid and causes an oops or ..?

> This patch corrects the order of operations to make the set-indicator
> calls (done in acquire_drc) before calling configure-connector.

Which commit added the code and/or caused it to be wrong?

  https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/Documentation/SubmittingPatches#n187

While looking at the code I notice it looks like we leak a reference if
dlpar_configure_connector() fails:

	parent = of_find_node_by_path("/cpus");
	if (!parent)
		return -ENODEV;

	dn = dlpar_configure_connector(cpu_to_be32(drc_index), parent);
	if (!dn)
		return -EINVAL;

	of_node_put(parent);

Please send a separate patch to fix that.

cheers