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iommu/vt-d: Fix RCU-list bugs in intel_iommu_init() 

commit 2d48ea0efb upstream.

There are several places traverse RCU-list without holding any lock in
intel_iommu_init(). Fix them by acquiring dmar_global_lock.

 WARNING: suspicious RCU usage
 -----------------------------
 drivers/iommu/intel-iommu.c:5216 RCU-list traversed in non-reader section!!

 other info that might help us debug this:

 rcu_scheduler_active = 2, debug_locks = 1
 no locks held by swapper/0/1.

 Call Trace:
  dump_stack+0xa0/0xea
  lockdep_rcu_suspicious+0x102/0x10b
  intel_iommu_init+0x947/0xb13
  pci_iommu_init+0x26/0x62
  do_one_initcall+0xfe/0x500
  kernel_init_freeable+0x45a/0x4f8
  kernel_init+0x11/0x139
  ret_from_fork+0x3a/0x50
 DMAR: Intel(R) Virtualization Technology for Directed I/O

Fixes: d8190dc638 ("iommu/vt-d: Enable DMA remapping after rmrr mapped")
Signed-off-by: Qian Cai <cai@lca.pw>
Acked-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
5.4-rM2-2.2.x-imx-squashed
Qian Cai 2020-03-05 15:00:46 -05:00 committed by Greg Kroah-Hartman
parent b8c3cbca80
commit 4f60640723
1 changed files with 4 additions and 1 deletions
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5
drivers/iommu/intel-iommu.c
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@ -5024,6 +5024,7 @@ int __init intel_iommu_init(void)
init_iommu_pm_ops();
down_read(&dmar_global_lock);
for_each_active_iommu(iommu, drhd) {
iommu_device_sysfs_add(&iommu->iommu, NULL,
intel_iommu_groups,
@ -5031,6 +5032,7 @@ int __init intel_iommu_init(void)
iommu_device_set_ops(&iommu->iommu, &intel_iommu_ops);
iommu_device_register(&iommu->iommu);
}
up_read(&dmar_global_lock);
bus_set_iommu(&pci_bus_type, &intel_iommu_ops);
if (si_domain && !hw_pass_through)
@ -5041,7 +5043,6 @@ int __init intel_iommu_init(void)
down_read(&dmar_global_lock);
if (probe_acpi_namespace_devices())
pr_warn("ACPI name space devices didn't probe correctly\n");
up_read(&dmar_global_lock);
/* Finally, we enable the DMA remapping hardware. */
for_each_iommu(iommu, drhd) {
@ -5050,6 +5051,8 @@ int __init intel_iommu_init(void)
iommu_disable_protect_mem_regions(iommu);
}
up_read(&dmar_global_lock);
pr_info("Intel(R) Virtualization Technology for Directed I/O\n");
intel_iommu_enabled = 1;