Re: [RHEL6.8 PATCH 3/3] iommu/vt-d: Fix dmar_domain leak in iommu_attach_device

[Linda Knippers <lknipper@redhat.com>]

This mail was sent by mistake.
Please ignore.

Sorry for the noise.

-- ljk

On 11/12/2015 09:47 AM, Shuah Khan wrote:
> On Tue, Nov 10, 2015 at 1:12 PM, Linda Knippers <lknipper@redhat.com> wrote:
>> bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1053879
>>
>> This is a backport to RHEL6 of Myron's backport to RHEL7.
>> http://post-office.corp.redhat.com/archives/rhkernel-list/2015-January/msg00231.html
>>
>> As Myron notes, the helper functions in the upstream code aren't
>> present in RHEL6 or RHEL7 so this code is less readable.  Myron
>> didn't backport the helpers because he's planning to rebase the
>> code in RHEL7.2.  I didn't backport the helpers to not introduce
>> more change.
>>
>> Myron's comments:
>>
>> Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1109829
>> Upstream Status: 62c22167dd70b730f61c2b88f950e98154a87980
>> >From Joerg's iommu/fixes branch intended for v3.19 -
>> https://git.kernel.org/cgit/linux/kernel/git/joro/iommu.git/commit/?h=iommu/fixes&id=62c22167dd70b730f61c2b88f950e98154a87980
>>
>> Conflict:
>>   This patch has a dependency on upstream commit ab8dfe2 ("iommu/vt-d:
>>   Introduce helper functions to improve code readability") which was
>>   introduced during v3.17-rc1.  RHEL7 does not have that commit, and
>> thus
>>   does not have 'domain_type_is_vm_or_si()'.  As such, this back-port
>> uses
>>   the older method used prior to the introduction of
>>   'domain_type_is_vm_or_si() (see upstream commit ab8dfe2).
>>
>> commit 62c22167dd70b730f61c2b88f950e98154a87980
>> Author: Joerg Roedel <jroedel@suse.de>
>> Date:   Tue Dec 9 12:56:45 2014 +0100
>>
>>     iommu/vt-d: Fix dmar_domain leak in iommu_attach_device
>>
>>     Since commit 1196c2f a domain is only destroyed in the
>>     notifier path if it is hot-unplugged. This caused a
>>     domain leakage in iommu_attach_device when a driver was
>>     unbound from the device and bound to VFIO. In this case the
>>     device is attached to a new domain and unlinked from the old
>>     domain. At this point nothing points to the old domain
>>     anymore and its memory is leaked.
>>     Fix this by explicitly freeing the old domain in
>>     iommu_attach_domain.
> 
> There is a lot of information in this commit log that isn't appropriate
> for a commit log. This information is better fit in the section that goes
> in the throw away comments section of the patch. This commit message
> is rather confusing and could use some refining.
> 
> thanks,
> -- Shuah
>>
>> Fixes: 1196c2f (iommu/vt-d: Fix dmar_domain leak in iommu_attach_device)
>> Cc: <stable@vger.kernel.org> # v3.18
>> Tested-by: Jerry Hoemann <jerry.hoemann@hp.com>
>> Signed-off-by: Joerg Roedel <jroedel@suse.de>
>> Signed-off-by: Linda Knippers <lknipper@redhat.com>
>> ---
>>  drivers/pci/intel-iommu.c | 5 +++++
>>  1 file changed, 5 insertions(+)
>>
>> diff --git a/drivers/pci/intel-iommu.c b/drivers/pci/intel-iommu.c
>> index 1c04ed8..80bd6d76 100644
>> --- a/drivers/pci/intel-iommu.c
>> +++ b/drivers/pci/intel-iommu.c
>> @@ -3851,6 +3851,11 @@ static int intel_iommu_attach_device(struct iommu_domain *domain,
>>                                 domain_remove_one_dev_info(old_domain, pdev);
>>                         else
>>                                 domain_remove_dev_info(old_domain);
>> +
>> +                       if (!(old_domain->flags & DOMAIN_FLAG_VIRTUAL_MACHINE) &&
>> +                           !(old_domain->flags & DOMAIN_FLAG_STATIC_IDENTITY) &&
>> +                           list_empty(&old_domain->devices))
>> +                               domain_exit(old_domain);
>>                 }
>>         }
>>
>> --
>> 1.8.3.1
>>
>> --
>> To unsubscribe from this list: send the line "unsubscribe stable" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html