diff options
| author | Lu Baolu <baolu.lu@linux.intel.com> | 2022-10-19 03:44:45 +0300 |
|---|---|---|
| committer | Joerg Roedel <jroedel@suse.de> | 2022-10-21 11:49:34 +0300 |
| commit | bf638a6513dda3021e3e90bdacb71c606bd0c305 (patch) | |
| tree | 71cbea98fd5acdd92eadfaaca82f12a752f688cd /drivers/iommu | |
| parent | 0251d0107cfb0bb5ab2d3f97710487b9522db020 (diff) | |
| download | linux-bf638a6513dda3021e3e90bdacb71c606bd0c305.tar.xz | |
iommu/vt-d: Use rcu_lock in get_resv_regions
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 57365a04c921 ("iommu: Move bus setup to IOMMU
device registration"), 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 in get_resv_regions to avoid
the lockdep splat.
Fixes: 57365a04c921 ("iommu: Move bus setup to IOMMU device registration")
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Tested-by: Alex Williamson <alex.williamson@redhat.com>
Link: https://lore.kernel.org/r/20220927053109.4053662-3-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 | 6 |
1 files 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)) { |