Messages in this thread | | | From | Lu Baolu <> | Subject | [PATCH 0/2] iommu/vt-d: Fix lockdep splat in intel_iommu_init() | Date | Tue, 27 Sep 2022 13:31:07 +0800 |
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Hi folks,
As commit c919739ce472 ("iommu/vt-d: Handle race between registration and device probe") highlights, a lockdep splat issue happens after moving iommu probing device process into iommu_device_register().
This is due to a conflict that get_resv_regions wants hold the dmar_global_lock, but it's also possible to be called from within a section where intel_iommu_init() already holds the lock.
Historically, before commit 5f64ce5411b46 ("iommu/vt-d: Duplicate iommu_resv_region objects per device list"), the rcu_lock is used in get_resv_regions. This commit converted it to dmar_global_lock in order to allowing sleeping in iommu_alloc_resv_region().
This aims to fix the lockdep issue by making iommu_alloc_resv_region() available in critical section and rolling dmar_global_lock back to rcu lock in get_resv_regions of the Intel IOMMU driver.
Best regards, baolu
Lu Baolu (2): iommu: Add gfp parameter to iommu_alloc_resv_region iommu/vt-d: Use rcu_lock in get_resv_regions
include/linux/iommu.h | 2 +- drivers/acpi/arm64/iort.c | 3 ++- drivers/iommu/amd/iommu.c | 7 ++++--- drivers/iommu/apple-dart.c | 2 +- drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 2 +- drivers/iommu/arm/arm-smmu/arm-smmu.c | 2 +- drivers/iommu/intel/iommu.c | 12 +++++++----- drivers/iommu/iommu.c | 7 ++++--- drivers/iommu/mtk_iommu.c | 3 ++- drivers/iommu/virtio-iommu.c | 9 ++++++--- 10 files changed, 29 insertions(+), 20 deletions(-)
-- 2.34.1
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