Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 4.4 29/38] iommu/vt-d: Fix dead-locks in disable_dmar_iommu() path | Date | Thu, 17 Nov 2016 11:33:07 +0100 |
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4.4-stable review patch. If anyone has any objections, please let me know.
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From: Joerg Roedel <jroedel@suse.de>
commit bea64033dd7b5fb6296eda8266acab6364ce1554 upstream.
It turns out that the disable_dmar_iommu() code-path tried to get the device_domain_lock recursivly, which will dead-lock when this code runs on dmar removal. Fix both code-paths that could lead to the dead-lock.
Fixes: 55d940430ab9 ('iommu/vt-d: Get rid of domain->iommu_lock') Signed-off-by: Joerg Roedel <jroedel@suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- drivers/iommu/intel-iommu.c | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-)
--- a/drivers/iommu/intel-iommu.c +++ b/drivers/iommu/intel-iommu.c @@ -1672,6 +1672,7 @@ static void disable_dmar_iommu(struct in if (!iommu->domains || !iommu->domain_ids) return; +again: spin_lock_irqsave(&device_domain_lock, flags); list_for_each_entry_safe(info, tmp, &device_domain_list, global) { struct dmar_domain *domain; @@ -1684,10 +1685,19 @@ static void disable_dmar_iommu(struct in domain = info->domain; - dmar_remove_one_dev_info(domain, info->dev); + __dmar_remove_one_dev_info(info); - if (!domain_type_is_vm_or_si(domain)) + if (!domain_type_is_vm_or_si(domain)) { + /* + * The domain_exit() function can't be called under + * device_domain_lock, as it takes this lock itself. + * So release the lock here and re-run the loop + * afterwards. + */ + spin_unlock_irqrestore(&device_domain_lock, flags); domain_exit(domain); + goto again; + } } spin_unlock_irqrestore(&device_domain_lock, flags);
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