[ Upstream commit a7755c3cfa5df755e39447b08c28203e011fb98c ]
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 Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/iommu/intel-iommu.c | 6 ++++++ 1 file changed, 6 insertions(+)
diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c index 10a45092d062..cb656f503604 100644 --- a/drivers/iommu/intel-iommu.c +++ b/drivers/iommu/intel-iommu.c @@ -3496,7 +3496,13 @@ 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; }