From 4c5502b1c5744b2090414e1b80ca6388d5c46e06 Mon Sep 17 00:00:00 2001 From: Suresh Siddha Date: Mon, 16 Mar 2009 17:04:53 -0700 Subject: [PATCH] x86, x2apic: fix lock ordering during IRQ migration Impact: fix potential deadlock on x2apic fix "hard-safe -> hard-unsafe lock order detected" with irq_2_ir_lock On x2apic enabled system: [ INFO: hard-safe -> hard-unsafe lock order detected ] 2.6.27-03151-g4480f15b #1 ------------------------------------------------------ swapper/1 [HC0[0]:SC0[0]:HE0:SE1] is trying to acquire: (irq_2_ir_lock){--..}, at: [] get_irte+0x2f/0x95 and this task is already holding: (&irq_desc_lock_class){+...}, at: [] setup_irq+0x67/0x281 which would create a new lock dependency: (&irq_desc_lock_class){+...} -> (irq_2_ir_lock){--..} but this new dependency connects a hard-irq-safe lock: (&irq_desc_lock_class){+...} ... which became hard-irq-safe at: [] 0xffffffffffffffff to a hard-irq-unsafe lock: (irq_2_ir_lock){--..} ... which became hard-irq-unsafe at: ... [] __lock_acquire+0x571/0x706 [] lock_acquire+0x55/0x71 [] _spin_lock+0x2c/0x38 [] alloc_irte+0x8a/0x14b [] setup_IO_APIC_irq+0x119/0x30e [] setup_IO_APIC+0x146/0x6e5 [] native_smp_prepare_cpus+0x24e/0x2e9 [] kernel_init+0x5a/0x176 [] child_rip+0xa/0x11 [] 0xffffffffffffffff Fix this theoretical lock order issue by using spin_lock_irqsave() instead of spin_lock() Signed-off-by: Suresh Siddha Signed-off-by: H. Peter Anvin --- drivers/pci/intr_remapping.c | 58 ++++++++++++++++++++---------------- 1 file changed, 33 insertions(+), 25 deletions(-) diff --git a/drivers/pci/intr_remapping.c b/drivers/pci/intr_remapping.c index 8e44db040db..5ffa65fffb6 100644 --- a/drivers/pci/intr_remapping.c +++ b/drivers/pci/intr_remapping.c @@ -117,21 +117,22 @@ int get_irte(int irq, struct irte *entry) { int index; struct irq_2_iommu *irq_iommu; + unsigned long flags; if (!entry) return -1; - spin_lock(&irq_2_ir_lock); + spin_lock_irqsave(&irq_2_ir_lock, flags); irq_iommu = valid_irq_2_iommu(irq); if (!irq_iommu) { - spin_unlock(&irq_2_ir_lock); + spin_unlock_irqrestore(&irq_2_ir_lock, flags); return -1; } index = irq_iommu->irte_index + irq_iommu->sub_handle; *entry = *(irq_iommu->iommu->ir_table->base + index); - spin_unlock(&irq_2_ir_lock); + spin_unlock_irqrestore(&irq_2_ir_lock, flags); return 0; } @@ -141,6 +142,7 @@ int alloc_irte(struct intel_iommu *iommu, int irq, u16 count) struct irq_2_iommu *irq_iommu; u16 index, start_index; unsigned int mask = 0; + unsigned long flags; int i; if (!count) @@ -170,7 +172,7 @@ int alloc_irte(struct intel_iommu *iommu, int irq, u16 count) return -1; } - spin_lock(&irq_2_ir_lock); + spin_lock_irqsave(&irq_2_ir_lock, flags); do { for (i = index; i < index + count; i++) if (table->base[i].present) @@ -182,7 +184,7 @@ int alloc_irte(struct intel_iommu *iommu, int irq, u16 count) index = (index + count) % INTR_REMAP_TABLE_ENTRIES; if (index == start_index) { - spin_unlock(&irq_2_ir_lock); + spin_unlock_irqrestore(&irq_2_ir_lock, flags); printk(KERN_ERR "can't allocate an IRTE\n"); return -1; } @@ -193,7 +195,7 @@ int alloc_irte(struct intel_iommu *iommu, int irq, u16 count) irq_iommu = irq_2_iommu_alloc(irq); if (!irq_iommu) { - spin_unlock(&irq_2_ir_lock); + spin_unlock_irqrestore(&irq_2_ir_lock, flags); printk(KERN_ERR "can't allocate irq_2_iommu\n"); return -1; } @@ -203,7 +205,7 @@ int alloc_irte(struct intel_iommu *iommu, int irq, u16 count) irq_iommu->sub_handle = 0; irq_iommu->irte_mask = mask; - spin_unlock(&irq_2_ir_lock); + spin_unlock_irqrestore(&irq_2_ir_lock, flags); return index; } @@ -223,30 +225,32 @@ int map_irq_to_irte_handle(int irq, u16 *sub_handle) { int index; struct irq_2_iommu *irq_iommu; + unsigned long flags; - spin_lock(&irq_2_ir_lock); + spin_lock_irqsave(&irq_2_ir_lock, flags); irq_iommu = valid_irq_2_iommu(irq); if (!irq_iommu) { - spin_unlock(&irq_2_ir_lock); + spin_unlock_irqrestore(&irq_2_ir_lock, flags); return -1; } *sub_handle = irq_iommu->sub_handle; index = irq_iommu->irte_index; - spin_unlock(&irq_2_ir_lock); + spin_unlock_irqrestore(&irq_2_ir_lock, flags); return index; } int set_irte_irq(int irq, struct intel_iommu *iommu, u16 index, u16 subhandle) { struct irq_2_iommu *irq_iommu; + unsigned long flags; - spin_lock(&irq_2_ir_lock); + spin_lock_irqsave(&irq_2_ir_lock, flags); irq_iommu = irq_2_iommu_alloc(irq); if (!irq_iommu) { - spin_unlock(&irq_2_ir_lock); + spin_unlock_irqrestore(&irq_2_ir_lock, flags); printk(KERN_ERR "can't allocate irq_2_iommu\n"); return -1; } @@ -256,7 +260,7 @@ int set_irte_irq(int irq, struct intel_iommu *iommu, u16 index, u16 subhandle) irq_iommu->sub_handle = subhandle; irq_iommu->irte_mask = 0; - spin_unlock(&irq_2_ir_lock); + spin_unlock_irqrestore(&irq_2_ir_lock, flags); return 0; } @@ -264,11 +268,12 @@ int set_irte_irq(int irq, struct intel_iommu *iommu, u16 index, u16 subhandle) int clear_irte_irq(int irq, struct intel_iommu *iommu, u16 index) { struct irq_2_iommu *irq_iommu; + unsigned long flags; - spin_lock(&irq_2_ir_lock); + spin_lock_irqsave(&irq_2_ir_lock, flags); irq_iommu = valid_irq_2_iommu(irq); if (!irq_iommu) { - spin_unlock(&irq_2_ir_lock); + spin_unlock_irqrestore(&irq_2_ir_lock, flags); return -1; } @@ -277,7 +282,7 @@ int clear_irte_irq(int irq, struct intel_iommu *iommu, u16 index) irq_iommu->sub_handle = 0; irq_2_iommu(irq)->irte_mask = 0; - spin_unlock(&irq_2_ir_lock); + spin_unlock_irqrestore(&irq_2_ir_lock, flags); return 0; } @@ -289,11 +294,12 @@ int modify_irte(int irq, struct irte *irte_modified) struct irte *irte; struct intel_iommu *iommu; struct irq_2_iommu *irq_iommu; + unsigned long flags; - spin_lock(&irq_2_ir_lock); + spin_lock_irqsave(&irq_2_ir_lock, flags); irq_iommu = valid_irq_2_iommu(irq); if (!irq_iommu) { - spin_unlock(&irq_2_ir_lock); + spin_unlock_irqrestore(&irq_2_ir_lock, flags); return -1; } @@ -306,7 +312,7 @@ int modify_irte(int irq, struct irte *irte_modified) __iommu_flush_cache(iommu, irte, sizeof(*irte)); rc = qi_flush_iec(iommu, index, 0); - spin_unlock(&irq_2_ir_lock); + spin_unlock_irqrestore(&irq_2_ir_lock, flags); return rc; } @@ -317,11 +323,12 @@ int flush_irte(int irq) int index; struct intel_iommu *iommu; struct irq_2_iommu *irq_iommu; + unsigned long flags; - spin_lock(&irq_2_ir_lock); + spin_lock_irqsave(&irq_2_ir_lock, flags); irq_iommu = valid_irq_2_iommu(irq); if (!irq_iommu) { - spin_unlock(&irq_2_ir_lock); + spin_unlock_irqrestore(&irq_2_ir_lock, flags); return -1; } @@ -330,7 +337,7 @@ int flush_irte(int irq) index = irq_iommu->irte_index + irq_iommu->sub_handle; rc = qi_flush_iec(iommu, index, irq_iommu->irte_mask); - spin_unlock(&irq_2_ir_lock); + spin_unlock_irqrestore(&irq_2_ir_lock, flags); return rc; } @@ -363,11 +370,12 @@ int free_irte(int irq) struct irte *irte; struct intel_iommu *iommu; struct irq_2_iommu *irq_iommu; + unsigned long flags; - spin_lock(&irq_2_ir_lock); + spin_lock_irqsave(&irq_2_ir_lock, flags); irq_iommu = valid_irq_2_iommu(irq); if (!irq_iommu) { - spin_unlock(&irq_2_ir_lock); + spin_unlock_irqrestore(&irq_2_ir_lock, flags); return -1; } @@ -387,7 +395,7 @@ int free_irte(int irq) irq_iommu->sub_handle = 0; irq_iommu->irte_mask = 0; - spin_unlock(&irq_2_ir_lock); + spin_unlock_irqrestore(&irq_2_ir_lock, flags); return rc; } -- 2.41.1