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From: Joerg Roedel <joro-zLv9SwRftAIdnm+yROfE0A@public.gmane.org>
To: Gregor Dick <gdick-s/n/eUQHGBpZroRs9YW3xA@public.gmane.org>
Cc: iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org,
	Kieran Mansley <kmansley-s/n/eUQHGBpZroRs9YW3xA@public.gmane.org>
Subject: Re: PROBLEM: Deadlock in attach_device() in AMD IOMMU driver
Date: Tue, 5 May 2015 17:33:44 +0200	[thread overview]
Message-ID: <20150505153344.GR15736@8bytes.org> (raw)
In-Reply-To: <5548D814.6020807-s/n/eUQHGBpZroRs9YW3xA@public.gmane.org>

On Tue, May 05, 2015 at 03:47:48PM +0100, Gregor Dick wrote:
> Hi Joerg,
> 
> On 05/05/15 15:41, Joerg Roedel wrote:
> >Do you see a real deadlock or only the lockdep warning? In the code it
> >looks like virtfn_add() takes the sriov->lock of the physical device
> >while pci_enable_ats() (when called from there) takes the sriov->lock of
> >the virtual function. In this case it couldn't deadlock.
> 
> The thread does deadlock. It looks like pci_enable_ats() takes
> dev->physfn->sriov->lock, where dev is the VF. I'd understood this to be
> a lock protecting SR-IOV state for all VFs configured on the PF (but I'm
> not familiar with the code at all!).

Okay, I'll have a look into the SLES12 kernel sources to check there.
Can you reproduce this with a recent upstream kernel?


	Joerg

  parent reply	other threads:[~2015-05-05 15:33 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-05-05  9:24 PROBLEM: Deadlock in attach_device() in AMD IOMMU driver Gregor Dick
     [not found] ` <55488C3D.50509-s/n/eUQHGBpZroRs9YW3xA@public.gmane.org>
2015-05-05 14:41   ` Joerg Roedel
     [not found]     ` <20150505144159.GI15736-zLv9SwRftAIdnm+yROfE0A@public.gmane.org>
2015-05-05 14:47       ` Gregor Dick
     [not found]         ` <5548D814.6020807-s/n/eUQHGBpZroRs9YW3xA@public.gmane.org>
2015-05-05 15:33           ` Joerg Roedel [this message]
     [not found]             ` <20150505153344.GR15736-zLv9SwRftAIdnm+yROfE0A@public.gmane.org>
2015-05-06 11:44               ` Gregor Dick
     [not found]                 ` <5549FEA1.9080801-s/n/eUQHGBpZroRs9YW3xA@public.gmane.org>
2015-05-11 10:15                   ` Joerg Roedel

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