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authorVasant Hegde <vasant.hegde@amd.com>2024-04-04 10:27:17 +0000
committerJoerg Roedel <jroedel@suse.de>2024-04-12 12:02:16 +0200
commit84b1cec4fac5889b6d138d4b5ff6f2d5ef126c5e (patch)
tree572a44e15f5c8952040017ace3befd6be8190b92
parentfec50db7033ea478773b159e0e2efb135270e3b7 (diff)
iommu/amd: Fix possible irq lock inversion dependency issue
LOCKDEP detector reported below warning: ---------------------------------------- [ 23.796949] ======================================================== [ 23.796950] WARNING: possible irq lock inversion dependency detected [ 23.796952] 6.8.0fix+ #811 Not tainted [ 23.796954] -------------------------------------------------------- [ 23.796954] kworker/0:1/8 just changed the state of lock: [ 23.796956] ff365325e084a9b8 (&domain->lock){..-.}-{3:3}, at: amd_iommu_flush_iotlb_all+0x1f/0x50 [ 23.796969] but this lock took another, SOFTIRQ-unsafe lock in the past: [ 23.796970] (pd_bitmap_lock){+.+.}-{3:3} [ 23.796972] and interrupts could create inverse lock ordering between them. [ 23.796973] other info that might help us debug this: [ 23.796974] Chain exists of: &domain->lock --> &dev_data->lock --> pd_bitmap_lock [ 23.796980] Possible interrupt unsafe locking scenario: [ 23.796981] CPU0 CPU1 [ 23.796982] ---- ---- [ 23.796983] lock(pd_bitmap_lock); [ 23.796985] local_irq_disable(); [ 23.796985] lock(&domain->lock); [ 23.796988] lock(&dev_data->lock); [ 23.796990] <Interrupt> [ 23.796991] lock(&domain->lock); Fix this issue by disabling interrupt when acquiring pd_bitmap_lock. Note that this is temporary fix. We have a plan to replace custom bitmap allocator with IDA allocator. Fixes: 87a6f1f22c97 ("iommu/amd: Introduce per-device domain ID to fix potential TLB aliasing issue") Reviewed-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com> Signed-off-by: Vasant Hegde <vasant.hegde@amd.com> Link: https://lore.kernel.org/r/20240404102717.6705-1-vasant.hegde@amd.com Signed-off-by: Joerg Roedel <jroedel@suse.de>
-rw-r--r--drivers/iommu/amd/iommu.c11
1 files changed, 7 insertions, 4 deletions
diff --git a/drivers/iommu/amd/iommu.c b/drivers/iommu/amd/iommu.c
index d35c1b8c8e65..e692217fcb28 100644
--- a/drivers/iommu/amd/iommu.c
+++ b/drivers/iommu/amd/iommu.c
@@ -1692,26 +1692,29 @@ int amd_iommu_complete_ppr(struct pci_dev *pdev, u32 pasid,
static u16 domain_id_alloc(void)
{
+ unsigned long flags;
int id;
- spin_lock(&pd_bitmap_lock);
+ spin_lock_irqsave(&pd_bitmap_lock, flags);
id = find_first_zero_bit(amd_iommu_pd_alloc_bitmap, MAX_DOMAIN_ID);
BUG_ON(id == 0);
if (id > 0 && id < MAX_DOMAIN_ID)
__set_bit(id, amd_iommu_pd_alloc_bitmap);
else
id = 0;
- spin_unlock(&pd_bitmap_lock);
+ spin_unlock_irqrestore(&pd_bitmap_lock, flags);
return id;
}
static void domain_id_free(int id)
{
- spin_lock(&pd_bitmap_lock);
+ unsigned long flags;
+
+ spin_lock_irqsave(&pd_bitmap_lock, flags);
if (id > 0 && id < MAX_DOMAIN_ID)
__clear_bit(id, amd_iommu_pd_alloc_bitmap);
- spin_unlock(&pd_bitmap_lock);
+ spin_unlock_irqrestore(&pd_bitmap_lock, flags);
}
static void free_gcr3_tbl_level1(u64 *tbl)