From: Lu Baolu <baolu.lu@linux.intel.com>
To: Joerg Roedel <joro@8bytes.org>, Kevin Tian <kevin.tian@intel.com>,
Will Deacon <will@kernel.org>,
Robin Murphy <robin.murphy@arm.com>
Cc: iommu@lists.linux.dev, linux-kernel@vger.kernel.org,
Lu Baolu <baolu.lu@linux.intel.com>
Subject: [PATCH 0/2] iommu/vt-d: Fix lockdep splat in intel_iommu_init()
Date: Tue, 27 Sep 2022 13:31:07 +0800 [thread overview]
Message-ID: <20220927053109.4053662-1-baolu.lu@linux.intel.com> (raw)
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
next reply other threads:[~2022-09-27 5:37 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-27 5:31 Lu Baolu [this message]
2022-09-27 5:31 ` [PATCH 1/2] iommu: Add gfp parameter to iommu_alloc_resv_region Lu Baolu
2022-09-27 5:31 ` [PATCH 2/2] iommu/vt-d: Use rcu_lock in get_resv_regions Lu Baolu
2022-09-30 2:23 ` [PATCH 0/2] iommu/vt-d: Fix lockdep splat in intel_iommu_init() Baolu Lu
2022-10-18 21:57 ` Alex Williamson
2022-10-19 0:49 ` Baolu Lu
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