* [PATCH 0/2] iommu/vt-d: Fix lockdep splat in intel_iommu_init()
@ 2022-09-27 5:31 Lu Baolu
2022-09-27 5:31 ` [PATCH 1/2] iommu: Add gfp parameter to iommu_alloc_resv_region Lu Baolu
` (4 more replies)
0 siblings, 5 replies; 6+ messages in thread
From: Lu Baolu @ 2022-09-27 5:31 UTC (permalink / raw)
To: Joerg Roedel, Kevin Tian, Will Deacon, Robin Murphy
Cc: iommu, linux-kernel, Lu Baolu
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
^ permalink raw reply [flat|nested] 6+ messages in thread* [PATCH 1/2] iommu: Add gfp parameter to iommu_alloc_resv_region 2022-09-27 5:31 [PATCH 0/2] iommu/vt-d: Fix lockdep splat in intel_iommu_init() Lu Baolu @ 2022-09-27 5:31 ` Lu Baolu 2022-09-27 5:31 ` [PATCH 2/2] iommu/vt-d: Use rcu_lock in get_resv_regions Lu Baolu ` (3 subsequent siblings) 4 siblings, 0 replies; 6+ messages in thread From: Lu Baolu @ 2022-09-27 5:31 UTC (permalink / raw) To: Joerg Roedel, Kevin Tian, Will Deacon, Robin Murphy Cc: iommu, linux-kernel, Lu Baolu Add gfp parameter to iommu_alloc_resv_region() for the callers to specify the memory allocation behavior. Thus iommu_alloc_resv_region() could also be available in critical contexts. Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com> --- 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 | 8 +++++--- drivers/iommu/iommu.c | 7 ++++--- drivers/iommu/mtk_iommu.c | 3 ++- drivers/iommu/virtio-iommu.c | 9 ++++++--- 10 files changed, 27 insertions(+), 18 deletions(-) diff --git a/include/linux/iommu.h b/include/linux/iommu.h index a325532aeab5..3c9da1f8979e 100644 --- a/include/linux/iommu.h +++ b/include/linux/iommu.h @@ -455,7 +455,7 @@ extern void iommu_set_default_translated(bool cmd_line); extern bool iommu_default_passthrough(void); extern struct iommu_resv_region * iommu_alloc_resv_region(phys_addr_t start, size_t length, int prot, - enum iommu_resv_type type); + enum iommu_resv_type type, gfp_t gfp); extern int iommu_get_group_resv_regions(struct iommu_group *group, struct list_head *head); diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c index ca2aed86b540..8059baf4ef27 100644 --- a/drivers/acpi/arm64/iort.c +++ b/drivers/acpi/arm64/iort.c @@ -1142,7 +1142,8 @@ static void iort_iommu_msi_get_resv_regions(struct device *dev, struct iommu_resv_region *region; region = iommu_alloc_resv_region(base + SZ_64K, SZ_64K, - prot, IOMMU_RESV_MSI); + prot, IOMMU_RESV_MSI, + GFP_KERNEL); if (region) list_add_tail(®ion->list, head); } diff --git a/drivers/iommu/amd/iommu.c b/drivers/iommu/amd/iommu.c index 65856e401949..d3b39d0416fa 100644 --- a/drivers/iommu/amd/iommu.c +++ b/drivers/iommu/amd/iommu.c @@ -2330,7 +2330,8 @@ static void amd_iommu_get_resv_regions(struct device *dev, type = IOMMU_RESV_RESERVED; region = iommu_alloc_resv_region(entry->address_start, - length, prot, type); + length, prot, type, + GFP_KERNEL); if (!region) { dev_err(dev, "Out of memory allocating dm-regions\n"); return; @@ -2340,14 +2341,14 @@ static void amd_iommu_get_resv_regions(struct device *dev, region = iommu_alloc_resv_region(MSI_RANGE_START, MSI_RANGE_END - MSI_RANGE_START + 1, - 0, IOMMU_RESV_MSI); + 0, IOMMU_RESV_MSI, GFP_KERNEL); if (!region) return; list_add_tail(®ion->list, head); region = iommu_alloc_resv_region(HT_RANGE_START, HT_RANGE_END - HT_RANGE_START + 1, - 0, IOMMU_RESV_RESERVED); + 0, IOMMU_RESV_RESERVED, GFP_KERNEL); if (!region) return; list_add_tail(®ion->list, head); diff --git a/drivers/iommu/apple-dart.c b/drivers/iommu/apple-dart.c index 4526575b999e..4f4a323be0d0 100644 --- a/drivers/iommu/apple-dart.c +++ b/drivers/iommu/apple-dart.c @@ -758,7 +758,7 @@ static void apple_dart_get_resv_regions(struct device *dev, region = iommu_alloc_resv_region(DOORBELL_ADDR, PAGE_SIZE, prot, - IOMMU_RESV_MSI); + IOMMU_RESV_MSI, GFP_KERNEL); if (!region) return; diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c index b788a38d8fdf..f1964261ceca 100644 --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c @@ -2757,7 +2757,7 @@ static void arm_smmu_get_resv_regions(struct device *dev, int prot = IOMMU_WRITE | IOMMU_NOEXEC | IOMMU_MMIO; region = iommu_alloc_resv_region(MSI_IOVA_BASE, MSI_IOVA_LENGTH, - prot, IOMMU_RESV_SW_MSI); + prot, IOMMU_RESV_SW_MSI, GFP_KERNEL); if (!region) return; diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.c b/drivers/iommu/arm/arm-smmu/arm-smmu.c index 6c1114a4d6cc..30dab1418e3f 100644 --- a/drivers/iommu/arm/arm-smmu/arm-smmu.c +++ b/drivers/iommu/arm/arm-smmu/arm-smmu.c @@ -1534,7 +1534,7 @@ static void arm_smmu_get_resv_regions(struct device *dev, int prot = IOMMU_WRITE | IOMMU_NOEXEC | IOMMU_MMIO; region = iommu_alloc_resv_region(MSI_IOVA_BASE, MSI_IOVA_LENGTH, - prot, IOMMU_RESV_SW_MSI); + prot, IOMMU_RESV_SW_MSI, GFP_KERNEL); if (!region) return; diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c index a8b36c3fddf1..d5965b4f8b60 100644 --- a/drivers/iommu/intel/iommu.c +++ b/drivers/iommu/intel/iommu.c @@ -4552,7 +4552,8 @@ static void intel_iommu_get_resv_regions(struct device *device, IOMMU_RESV_DIRECT_RELAXABLE : IOMMU_RESV_DIRECT; resv = iommu_alloc_resv_region(rmrr->base_address, - length, prot, type); + length, prot, type, + GFP_KERNEL); if (!resv) break; @@ -4567,7 +4568,8 @@ static void intel_iommu_get_resv_regions(struct device *device, if ((pdev->class >> 8) == PCI_CLASS_BRIDGE_ISA) { reg = iommu_alloc_resv_region(0, 1UL << 24, prot, - IOMMU_RESV_DIRECT_RELAXABLE); + IOMMU_RESV_DIRECT_RELAXABLE, + GFP_KERNEL); if (reg) list_add_tail(®->list, head); } @@ -4576,7 +4578,7 @@ static void intel_iommu_get_resv_regions(struct device *device, reg = iommu_alloc_resv_region(IOAPIC_RANGE_START, IOAPIC_RANGE_END - IOAPIC_RANGE_START + 1, - 0, IOMMU_RESV_MSI); + 0, IOMMU_RESV_MSI, GFP_KERNEL); if (!reg) return; list_add_tail(®->list, head); diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c index 4893c2429ca5..65a3b3d886dc 100644 --- a/drivers/iommu/iommu.c +++ b/drivers/iommu/iommu.c @@ -504,7 +504,7 @@ static int iommu_insert_resv_region(struct iommu_resv_region *new, LIST_HEAD(stack); nr = iommu_alloc_resv_region(new->start, new->length, - new->prot, new->type); + new->prot, new->type, GFP_KERNEL); if (!nr) return -ENOMEM; @@ -2579,11 +2579,12 @@ EXPORT_SYMBOL(iommu_put_resv_regions); struct iommu_resv_region *iommu_alloc_resv_region(phys_addr_t start, size_t length, int prot, - enum iommu_resv_type type) + enum iommu_resv_type type, + gfp_t gfp) { struct iommu_resv_region *region; - region = kzalloc(sizeof(*region), GFP_KERNEL); + region = kzalloc(sizeof(*region), gfp); if (!region) return NULL; diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c index 5a4e00e4bbbc..2ab2ecfe01f8 100644 --- a/drivers/iommu/mtk_iommu.c +++ b/drivers/iommu/mtk_iommu.c @@ -917,7 +917,8 @@ static void mtk_iommu_get_resv_regions(struct device *dev, continue; region = iommu_alloc_resv_region(resv->iova_base, resv->size, - prot, IOMMU_RESV_RESERVED); + prot, IOMMU_RESV_RESERVED, + GFP_KERNEL); if (!region) return; diff --git a/drivers/iommu/virtio-iommu.c b/drivers/iommu/virtio-iommu.c index b7c22802f57c..8b1b5c270e50 100644 --- a/drivers/iommu/virtio-iommu.c +++ b/drivers/iommu/virtio-iommu.c @@ -490,11 +490,13 @@ static int viommu_add_resv_mem(struct viommu_endpoint *vdev, fallthrough; case VIRTIO_IOMMU_RESV_MEM_T_RESERVED: region = iommu_alloc_resv_region(start, size, 0, - IOMMU_RESV_RESERVED); + IOMMU_RESV_RESERVED, + GFP_KERNEL); break; case VIRTIO_IOMMU_RESV_MEM_T_MSI: region = iommu_alloc_resv_region(start, size, prot, - IOMMU_RESV_MSI); + IOMMU_RESV_MSI, + GFP_KERNEL); break; } if (!region) @@ -909,7 +911,8 @@ static void viommu_get_resv_regions(struct device *dev, struct list_head *head) */ if (!msi) { msi = iommu_alloc_resv_region(MSI_IOVA_BASE, MSI_IOVA_LENGTH, - prot, IOMMU_RESV_SW_MSI); + prot, IOMMU_RESV_SW_MSI, + GFP_KERNEL); if (!msi) return; -- 2.34.1 ^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH 2/2] iommu/vt-d: Use rcu_lock in get_resv_regions 2022-09-27 5:31 [PATCH 0/2] iommu/vt-d: Fix lockdep splat in intel_iommu_init() Lu Baolu 2022-09-27 5:31 ` [PATCH 1/2] iommu: Add gfp parameter to iommu_alloc_resv_region Lu Baolu @ 2022-09-27 5:31 ` Lu Baolu 2022-09-30 2:23 ` [PATCH 0/2] iommu/vt-d: Fix lockdep splat in intel_iommu_init() Baolu Lu ` (2 subsequent siblings) 4 siblings, 0 replies; 6+ messages in thread From: Lu Baolu @ 2022-09-27 5:31 UTC (permalink / raw) To: Joerg Roedel, Kevin Tian, Will Deacon, Robin Murphy Cc: iommu, linux-kernel, Lu Baolu Commit 5f64ce5411b46 ("iommu/vt-d: Duplicate iommu_resv_region objects per device list") converted rcu_lock in get_resv_regions to dmar_global_lock to allow sleeping in iommu_alloc_resv_region(). This introduced possible recursive locking if get_resv_regions is called from within a section where intel_iommu_init() already holds dmar_global_lock. Especially after commit c919739ce4721 ("iommu/vt-d: Handle race between registration and device probe"), below lockdep splats could always be seen. ============================================ WARNING: possible recursive locking detected 6.0.0-rc4+ #325 Tainted: G I -------------------------------------------- swapper/0/1 is trying to acquire lock: ffffffffa8a18c90 (dmar_global_lock){++++}-{3:3}, at: intel_iommu_get_resv_regions+0x25/0x270 but task is already holding lock: ffffffffa8a18c90 (dmar_global_lock){++++}-{3:3}, at: intel_iommu_init+0x36d/0x6ea ... Call Trace: <TASK> dump_stack_lvl+0x48/0x5f __lock_acquire.cold.73+0xad/0x2bb lock_acquire+0xc2/0x2e0 ? intel_iommu_get_resv_regions+0x25/0x270 ? lock_is_held_type+0x9d/0x110 down_read+0x42/0x150 ? intel_iommu_get_resv_regions+0x25/0x270 intel_iommu_get_resv_regions+0x25/0x270 iommu_create_device_direct_mappings.isra.28+0x8d/0x1c0 ? iommu_get_dma_cookie+0x6d/0x90 bus_iommu_probe+0x19f/0x2e0 iommu_device_register+0xd4/0x130 intel_iommu_init+0x3e1/0x6ea ? iommu_setup+0x289/0x289 ? rdinit_setup+0x34/0x34 pci_iommu_init+0x12/0x3a do_one_initcall+0x65/0x320 ? rdinit_setup+0x34/0x34 ? rcu_read_lock_sched_held+0x5a/0x80 kernel_init_freeable+0x28a/0x2f3 ? rest_init+0x1b0/0x1b0 kernel_init+0x1a/0x130 ret_from_fork+0x1f/0x30 </TASK> This rolls back dmar_global_lock to rcu_lock to avoid the lockdep splat. Fixes: c919739ce4721 ("iommu/vt-d: Handle race between registration and device probe") Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com> --- drivers/iommu/intel/iommu.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c index d5965b4f8b60..b3cf0f991e29 100644 --- a/drivers/iommu/intel/iommu.c +++ b/drivers/iommu/intel/iommu.c @@ -4534,7 +4534,7 @@ static void intel_iommu_get_resv_regions(struct device *device, struct device *i_dev; int i; - down_read(&dmar_global_lock); + rcu_read_lock(); for_each_rmrr_units(rmrr) { for_each_active_dev_scope(rmrr->devices, rmrr->devices_cnt, i, i_dev) { @@ -4553,14 +4553,14 @@ static void intel_iommu_get_resv_regions(struct device *device, resv = iommu_alloc_resv_region(rmrr->base_address, length, prot, type, - GFP_KERNEL); + GFP_ATOMIC); if (!resv) break; list_add_tail(&resv->list, head); } } - up_read(&dmar_global_lock); + rcu_read_unlock(); #ifdef CONFIG_INTEL_IOMMU_FLOPPY_WA if (dev_is_pci(device)) { -- 2.34.1 ^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH 0/2] iommu/vt-d: Fix lockdep splat in intel_iommu_init() 2022-09-27 5:31 [PATCH 0/2] iommu/vt-d: Fix lockdep splat in intel_iommu_init() Lu Baolu 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 ` Baolu Lu 2022-10-18 21:57 ` Alex Williamson 2022-10-19 0:49 ` Baolu Lu 4 siblings, 0 replies; 6+ messages in thread From: Baolu Lu @ 2022-09-30 2:23 UTC (permalink / raw) To: Joerg Roedel, Kevin Tian, Will Deacon, Robin Murphy Cc: baolu.lu, iommu, linux-kernel On 9/27/22 1:31 PM, Lu Baolu wrote: > 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. A gentle ping. Any comments to this fix? It's better to work out a feasible solution before the users keep complaining. :-) Best regards, baolu ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH 0/2] iommu/vt-d: Fix lockdep splat in intel_iommu_init() 2022-09-27 5:31 [PATCH 0/2] iommu/vt-d: Fix lockdep splat in intel_iommu_init() Lu Baolu ` (2 preceding siblings ...) 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 4 siblings, 0 replies; 6+ messages in thread From: Alex Williamson @ 2022-10-18 21:57 UTC (permalink / raw) To: Lu Baolu Cc: Joerg Roedel, Kevin Tian, Will Deacon, Robin Murphy, iommu, linux-kernel On Tue, 27 Sep 2022 13:31:07 +0800 Lu Baolu <baolu.lu@linux.intel.com> wrote: > 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(-) Resolves the regression for me. Hopefully Joerg will queue this for 6.1-rc. Thanks! Tested-by: Alex Williamson <alex.williamson@redhat.com> ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH 0/2] iommu/vt-d: Fix lockdep splat in intel_iommu_init() 2022-09-27 5:31 [PATCH 0/2] iommu/vt-d: Fix lockdep splat in intel_iommu_init() Lu Baolu ` (3 preceding siblings ...) 2022-10-18 21:57 ` Alex Williamson @ 2022-10-19 0:49 ` Baolu Lu 4 siblings, 0 replies; 6+ messages in thread From: Baolu Lu @ 2022-10-19 0:49 UTC (permalink / raw) To: Joerg Roedel, Kevin Tian, Will Deacon, Robin Murphy Cc: baolu.lu, iommu, linux-kernel On 9/27/22 1:31 PM, Lu Baolu wrote: > 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 Patches has been queued for v6.1. https://lore.kernel.org/linux-iommu/20221019004447.4563-1-baolu.lu@linux.intel.com/ Best regards, baolu ^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2022-10-19 0:55 UTC | newest] Thread overview: 6+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2022-09-27 5:31 [PATCH 0/2] iommu/vt-d: Fix lockdep splat in intel_iommu_init() Lu Baolu 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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