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Subject: Re: [PATCH] cxl: use pcibios_free_controller_deferred() when
 removing vPHBs
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Andrew Donnellan <andrew.donnellan@au1.ibm.com>,
 linuxppc-dev@lists.ozlabs.org
Cc: clombard@linux.vnet.ibm.com, linux-pci@vger.kernel.org,
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Date: Tue, 30 Aug 2016 12:36:05 +1000
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On Tue, 2016-08-30 at 11:58 +1000, Andrew Donnellan wrote:
> Hi stable team,
> 
> The following patch, which ended up upstream as 
> 6f38a8b9a45833495dc878c335c5431cd98a16ed:
> 
> On 18/08/16 17:35, Andrew Donnellan wrote:
> > 
> > When cxl removes a vPHB, it's possible that the pci_controller may be freed
> > before all references to the devices on the vPHB have been released. This
> > in turn causes an invalid memory access when the devices are eventually
> > released, as pcibios_release_device() attempts to call the phb's
> > release_device hook.
> > 
> > In cxl_pci_vphb_remove(), remove the existing call to
> > pcibios_free_controller(). Instead, use
> > pcibios_free_controller_deferred() to free the pci_controller after all
> > devices have been released. Export pci_set_host_bridge_release() so we can
> > do this.
> > 
> > Cc: stable@vger.kernel.org
> > > > Signed-off-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
> > 
> > ---
> > 
> > > > This patch requires http://patchwork.ozlabs.org/patch/658324/. It should go
> > through the powerpc tree.
> 
> This depends on 2dd9c11b9d4dfbd6c070eab7b81197f65e82f1a0 which didn't 
> end up being tagged as cc: stable. It also ended up being applied in the 
> wrong order in the powerpc/fixes tree...

My fault. Best at this point is to also apply 2dd9c11b9d4dfbd6c070eab7b81197f65e82f1a0
to stable.

Cheers,
Ben.