diff options
| author | Dave Jiang <dave.jiang@intel.com> | 2019-05-21 15:30:15 +0800 |
|---|---|---|
| committer | Joerg Roedel <jroedel@suse.de> | 2019-05-27 16:32:43 +0200 |
| commit | 7560cc3ca7d9d11555f80c830544e463fcdb28b8 (patch) | |
| tree | 4dbbd621caa750f194003731655fc8e4577415f4 /drivers/iommu | |
| parent | 24f307d8abf79486dd3c1b645037df7d91602aaa (diff) | |
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.c | 7 |
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)) { |