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authorDave Jiang <dave.jiang@intel.com>2019-05-21 15:30:15 +0800
committerJoerg Roedel <jroedel@suse.de>2019-05-27 16:32:43 +0200
commit7560cc3ca7d9d11555f80c830544e463fcdb28b8 (patch)
tree4dbbd621caa750f194003731655fc8e4577415f4 /drivers/iommu
parent24f307d8abf79486dd3c1b645037df7d91602aaa (diff)
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iommu/vt-d: Fix lock inversion between iommu->lock and device_domain_lock
Lockdep debug reported lock inversion related with the iommu code caused by dmar_insert_one_dev_info() grabbing the iommu->lock and the device_domain_lock out of order versus the code path in iommu_flush_dev_iotlb(). Expanding the scope of the iommu->lock and reversing the order of lock acquisition fixes the issue. [ 76.238180] dsa_bus wq0.0: dsa wq wq0.0 disabled [ 76.248706] [ 76.250486] ======================================================== [ 76.257113] WARNING: possible irq lock inversion dependency detected [ 76.263736] 5.1.0-rc5+ #162 Not tainted [ 76.267854] -------------------------------------------------------- [ 76.274485] systemd-journal/521 just changed the state of lock: [ 76.280685] 0000000055b330f5 (device_domain_lock){..-.}, at: iommu_flush_dev_iotlb.part.63+0x29/0x90 [ 76.290099] but this lock took another, SOFTIRQ-unsafe lock in the past: [ 76.297093] (&(&iommu->lock)->rlock){+.+.} [ 76.297094] [ 76.297094] [ 76.297094] and interrupts could create inverse lock ordering between them. [ 76.297094] [ 76.314257] [ 76.314257] other info that might help us debug this: [ 76.321448] Possible interrupt unsafe locking scenario: [ 76.321448] [ 76.328907] CPU0 CPU1 [ 76.333777] ---- ---- [ 76.338642] lock(&(&iommu->lock)->rlock); [ 76.343165] local_irq_disable(); [ 76.349422] lock(device_domain_lock); [ 76.356116] lock(&(&iommu->lock)->rlock); [ 76.363154] <Interrupt> [ 76.366134] lock(device_domain_lock); [ 76.370548] [ 76.370548] *** DEADLOCK *** Fixes: 745f2586e78e ("iommu/vt-d: Simplify function get_domain_for_dev()") Signed-off-by: Dave Jiang <dave.jiang@intel.com> Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com> Signed-off-by: Joerg Roedel <jroedel@suse.de>
Diffstat (limited to 'drivers/iommu')
-rw-r--r--drivers/iommu/intel-iommu.c7
1 files changed, 4 insertions, 3 deletions
diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index a209199f3af6..91f4912c09c6 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -2512,6 +2512,7 @@ static struct dmar_domain *dmar_insert_one_dev_info(struct intel_iommu *iommu,
}
}
+ spin_lock(&iommu->lock);
spin_lock_irqsave(&device_domain_lock, flags);
if (dev)
found = find_domain(dev);
@@ -2527,17 +2528,16 @@ static struct dmar_domain *dmar_insert_one_dev_info(struct intel_iommu *iommu,
if (found) {
spin_unlock_irqrestore(&device_domain_lock, flags);
+ spin_unlock(&iommu->lock);
free_devinfo_mem(info);
/* Caller must free the original domain */
return found;
}
- spin_lock(&iommu->lock);
ret = domain_attach_iommu(domain, iommu);
- spin_unlock(&iommu->lock);
-
if (ret) {
spin_unlock_irqrestore(&device_domain_lock, flags);
+ spin_unlock(&iommu->lock);
free_devinfo_mem(info);
return NULL;
}
@@ -2547,6 +2547,7 @@ static struct dmar_domain *dmar_insert_one_dev_info(struct intel_iommu *iommu,
if (dev)
dev->archdata.iommu = info;
spin_unlock_irqrestore(&device_domain_lock, flags);
+ spin_unlock(&iommu->lock);
/* PASID table is mandatory for a PCI device in scalable mode. */
if (dev && dev_is_pci(dev) && sm_supported(iommu)) {