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authorLu Baolu <baolu.lu@linux.intel.com>2019-04-19 09:43:29 +0300
committerJoerg Roedel <jroedel@suse.de>2019-04-26 17:43:21 +0300
commita7755c3cfa5df755e39447b08c28203e011fb98c (patch)
tree02c761285bf1cd0b6eacf76f75bb5a55c29fdd12 /drivers/iommu
parent553d66cb1e8667aadb57e3804775c5ce1724a49b (diff)
downloadlinux-a7755c3cfa5df755e39447b08c28203e011fb98c.tar.xz
iommu/vt-d: Don't request page request irq under dmar_global_lock
Requesting page reqest irq under dmar_global_lock could cause potential lock race condition (caught by lockdep). [ 4.100055] ====================================================== [ 4.100063] WARNING: possible circular locking dependency detected [ 4.100072] 5.1.0-rc4+ #2169 Not tainted [ 4.100078] ------------------------------------------------------ [ 4.100086] swapper/0/1 is trying to acquire lock: [ 4.100094] 000000007dcbe3c3 (dmar_lock){+.+.}, at: dmar_alloc_hwirq+0x35/0x140 [ 4.100112] but task is already holding lock: [ 4.100120] 0000000060bbe946 (dmar_global_lock){++++}, at: intel_iommu_init+0x191/0x1438 [ 4.100136] which lock already depends on the new lock. [ 4.100146] the existing dependency chain (in reverse order) is: [ 4.100155] -> #2 (dmar_global_lock){++++}: [ 4.100169] down_read+0x44/0xa0 [ 4.100178] intel_irq_remapping_alloc+0xb2/0x7b0 [ 4.100186] mp_irqdomain_alloc+0x9e/0x2e0 [ 4.100195] __irq_domain_alloc_irqs+0x131/0x330 [ 4.100203] alloc_isa_irq_from_domain.isra.4+0x9a/0xd0 [ 4.100212] mp_map_pin_to_irq+0x244/0x310 [ 4.100221] setup_IO_APIC+0x757/0x7ed [ 4.100229] x86_late_time_init+0x17/0x1c [ 4.100238] start_kernel+0x425/0x4e3 [ 4.100247] secondary_startup_64+0xa4/0xb0 [ 4.100254] -> #1 (irq_domain_mutex){+.+.}: [ 4.100265] __mutex_lock+0x7f/0x9d0 [ 4.100273] __irq_domain_add+0x195/0x2b0 [ 4.100280] irq_domain_create_hierarchy+0x3d/0x40 [ 4.100289] msi_create_irq_domain+0x32/0x110 [ 4.100297] dmar_alloc_hwirq+0x111/0x140 [ 4.100305] dmar_set_interrupt.part.14+0x1a/0x70 [ 4.100314] enable_drhd_fault_handling+0x2c/0x6c [ 4.100323] apic_bsp_setup+0x75/0x7a [ 4.100330] x86_late_time_init+0x17/0x1c [ 4.100338] start_kernel+0x425/0x4e3 [ 4.100346] secondary_startup_64+0xa4/0xb0 [ 4.100352] -> #0 (dmar_lock){+.+.}: [ 4.100364] lock_acquire+0xb4/0x1c0 [ 4.100372] __mutex_lock+0x7f/0x9d0 [ 4.100379] dmar_alloc_hwirq+0x35/0x140 [ 4.100389] intel_svm_enable_prq+0x61/0x180 [ 4.100397] intel_iommu_init+0x1128/0x1438 [ 4.100406] pci_iommu_init+0x16/0x3f [ 4.100414] do_one_initcall+0x5d/0x2be [ 4.100422] kernel_init_freeable+0x1f0/0x27c [ 4.100431] kernel_init+0xa/0x110 [ 4.100438] ret_from_fork+0x3a/0x50 [ 4.100444] other info that might help us debug this: [ 4.100454] Chain exists of: dmar_lock --> irq_domain_mutex --> dmar_global_lock [ 4.100469] Possible unsafe locking scenario: [ 4.100476] CPU0 CPU1 [ 4.100483] ---- ---- [ 4.100488] lock(dmar_global_lock); [ 4.100495] lock(irq_domain_mutex); [ 4.100503] lock(dmar_global_lock); [ 4.100512] lock(dmar_lock); [ 4.100518] *** DEADLOCK *** Cc: Ashok Raj <ashok.raj@intel.com> Cc: Jacob Pan <jacob.jun.pan@linux.intel.com> Cc: Kevin Tian <kevin.tian@intel.com> Reported-by: Dave Jiang <dave.jiang@intel.com> Fixes: a222a7f0bb6c9 ("iommu/vt-d: Implement page request handling") Signed-off-by: Lu Baolu <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.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index d93c4bd7de75..52311a6d9d3f 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -3498,7 +3498,13 @@ domains_done:
#ifdef CONFIG_INTEL_IOMMU_SVM
if (pasid_supported(iommu) && ecap_prs(iommu->ecap)) {
+ /*
+ * Call dmar_alloc_hwirq() with dmar_global_lock held,
+ * could cause possible lock race condition.
+ */
+ up_write(&dmar_global_lock);
ret = intel_svm_enable_prq(iommu);
+ down_write(&dmar_global_lock);
if (ret)
goto free_iommu;
}