From: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
[ 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@xxxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20200927062428.13713-1-baolu.lu@xxxxxxxxxxxxxxx
Signed-off-by: Joerg Roedel <jroedel@xxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
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);
--
2.25.1
