From: Lu Baolu baolu.lu@linux.intel.com
[ Upstream commit 420d42f6f9db27d88bc4f83e3e668fcdacbf7e29 ]
Lock(&iommu->lock) without disabling irq causes lockdep warnings.
======================================================== WARNING: possible irq lock inversion dependency detected 5.11.0-rc1+ #828 Not tainted -------------------------------------------------------- kworker/0:1H/120 just changed the state of lock: ffffffffad9ea1b8 (device_domain_lock){..-.}-{2:2}, at: iommu_flush_dev_iotlb.part.0+0x32/0x120 but this lock took another, SOFTIRQ-unsafe lock in the past: (&iommu->lock){+.+.}-{2:2}
and interrupts could create inverse lock ordering between them.
other info that might help us debug this: Possible interrupt unsafe locking scenario:
CPU0 CPU1 ---- ---- lock(&iommu->lock); local_irq_disable(); lock(device_domain_lock); lock(&iommu->lock); <Interrupt> lock(device_domain_lock);
*** DEADLOCK ***
Signed-off-by: Lu Baolu baolu.lu@linux.intel.com Link: https://lore.kernel.org/r/20201231005323.2178523-5-baolu.lu@linux.intel.com Signed-off-by: Will Deacon will@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/iommu/intel/svm.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-)
diff --git a/drivers/iommu/intel/svm.c b/drivers/iommu/intel/svm.c index 3242ebd0bca36..267001e8076cd 100644 --- a/drivers/iommu/intel/svm.c +++ b/drivers/iommu/intel/svm.c @@ -281,6 +281,7 @@ int intel_svm_bind_gpasid(struct iommu_domain *domain, struct device *dev, struct dmar_domain *dmar_domain; struct device_domain_info *info; struct intel_svm *svm = NULL; + unsigned long iflags; int ret = 0;
if (WARN_ON(!iommu) || !data) @@ -381,12 +382,12 @@ int intel_svm_bind_gpasid(struct iommu_domain *domain, struct device *dev, * each bind of a new device even with an existing PASID, we need to * call the nested mode setup function here. */ - spin_lock(&iommu->lock); + spin_lock_irqsave(&iommu->lock, iflags); ret = intel_pasid_setup_nested(iommu, dev, (pgd_t *)(uintptr_t)data->gpgd, data->hpasid, &data->vendor.vtd, dmar_domain, data->addr_width); - spin_unlock(&iommu->lock); + spin_unlock_irqrestore(&iommu->lock, iflags); if (ret) { dev_err_ratelimited(dev, "Failed to set up PASID %llu in nested mode, Err %d\n", data->hpasid, ret); @@ -486,6 +487,7 @@ intel_svm_bind_mm(struct device *dev, unsigned int flags, struct device_domain_info *info; struct intel_svm_dev *sdev; struct intel_svm *svm = NULL; + unsigned long iflags; int pasid_max; int ret;
@@ -605,14 +607,14 @@ intel_svm_bind_mm(struct device *dev, unsigned int flags, } }
- spin_lock(&iommu->lock); + spin_lock_irqsave(&iommu->lock, iflags); ret = intel_pasid_setup_first_level(iommu, dev, mm ? mm->pgd : init_mm.pgd, svm->pasid, FLPT_DEFAULT_DID, (mm ? 0 : PASID_FLAG_SUPERVISOR_MODE) | (cpu_feature_enabled(X86_FEATURE_LA57) ? PASID_FLAG_FL5LP : 0)); - spin_unlock(&iommu->lock); + spin_unlock_irqrestore(&iommu->lock, iflags); if (ret) { if (mm) mmu_notifier_unregister(&svm->notifier, mm); @@ -632,14 +634,14 @@ intel_svm_bind_mm(struct device *dev, unsigned int flags, * Binding a new device with existing PASID, need to setup * the PASID entry. */ - spin_lock(&iommu->lock); + spin_lock_irqsave(&iommu->lock, iflags); ret = intel_pasid_setup_first_level(iommu, dev, mm ? mm->pgd : init_mm.pgd, svm->pasid, FLPT_DEFAULT_DID, (mm ? 0 : PASID_FLAG_SUPERVISOR_MODE) | (cpu_feature_enabled(X86_FEATURE_LA57) ? PASID_FLAG_FL5LP : 0)); - spin_unlock(&iommu->lock); + spin_unlock_irqrestore(&iommu->lock, iflags); if (ret) { kfree(sdev); goto out;