From: Lu Baolu baolu.lu@linux.intel.com
[ Upstream commit 1a3f2fd7fc4e8f24510830e265de2ffb8e3300d2 ]
Lock(&iommu->lock) without disabling irq causes lockdep warnings.
[ 12.703950] ======================================================== [ 12.703962] WARNING: possible irq lock inversion dependency detected [ 12.703975] 5.9.0-rc6+ #659 Not tainted [ 12.703983] -------------------------------------------------------- [ 12.703995] systemd-udevd/284 just changed the state of lock: [ 12.704007] ffffffffbd6ff4d8 (device_domain_lock){..-.}-{2:2}, at: iommu_flush_dev_iotlb.part.57+0x2e/0x90 [ 12.704031] but this lock took another, SOFTIRQ-unsafe lock in the past: [ 12.704043] (&iommu->lock){+.+.}-{2:2} [ 12.704045]
and interrupts could create inverse lock ordering between them.
[ 12.704073] other info that might help us debug this: [ 12.704085] Possible interrupt unsafe locking scenario:
[ 12.704097] CPU0 CPU1 [ 12.704106] ---- ---- [ 12.704115] lock(&iommu->lock); [ 12.704123] local_irq_disable(); [ 12.704134] lock(device_domain_lock); [ 12.704146] lock(&iommu->lock); [ 12.704158] <Interrupt> [ 12.704164] lock(device_domain_lock); [ 12.704174] *** DEADLOCK ***
Signed-off-by: Lu Baolu baolu.lu@linux.intel.com Link: https://lore.kernel.org/r/20200927062428.13713-1-baolu.lu@linux.intel.com Signed-off-by: Joerg Roedel jroedel@suse.de Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/iommu/intel/iommu.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c index fbe0b0cc56edf..24a84d294fd01 100644 --- a/drivers/iommu/intel/iommu.c +++ b/drivers/iommu/intel/iommu.c @@ -2617,7 +2617,7 @@ static struct dmar_domain *dmar_insert_one_dev_info(struct intel_iommu *iommu, }
/* Setup the PASID entry for requests without PASID: */ - spin_lock(&iommu->lock); + spin_lock_irqsave(&iommu->lock, flags); if (hw_pass_through && domain_type_is_si(domain)) ret = intel_pasid_setup_pass_through(iommu, domain, dev, PASID_RID2PASID); @@ -2627,7 +2627,7 @@ static struct dmar_domain *dmar_insert_one_dev_info(struct intel_iommu *iommu, else ret = intel_pasid_setup_second_level(iommu, domain, dev, PASID_RID2PASID); - spin_unlock(&iommu->lock); + spin_unlock_irqrestore(&iommu->lock, flags); if (ret) { dev_err(dev, "Setup RID2PASID failed\n"); dmar_remove_one_dev_info(dev);