From 920fcc7adc73891a417857c7d6f026f854ec3b0f Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Fri, 14 Mar 2025 20:10:48 -0700 Subject: [PATCH] iommu/amd: Ensure GA log notifier callbacks finish running before module unload [ Upstream commit 94c721ea03c7078163f41dbaa101ac721ddac329 ] Synchronize RCU when unregistering KVM's GA log notifier to ensure all in-flight interrupt handlers complete before KVM-the module is unloaded. Signed-off-by: Sean Christopherson Link: https://lore.kernel.org/r/20250315031048.2374109-1-seanjc@google.com Signed-off-by: Joerg Roedel Signed-off-by: Sasha Levin --- drivers/iommu/amd/iommu.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/drivers/iommu/amd/iommu.c b/drivers/iommu/amd/iommu.c index 83c5d786686d..a5d6d786dba5 100644 --- a/drivers/iommu/amd/iommu.c +++ b/drivers/iommu/amd/iommu.c @@ -780,6 +780,14 @@ int amd_iommu_register_ga_log_notifier(int (*notifier)(u32)) { iommu_ga_log_notifier = notifier; + /* + * Ensure all in-flight IRQ handlers run to completion before returning + * to the caller, e.g. to ensure module code isn't unloaded while it's + * being executed in the IRQ handler. + */ + if (!notifier) + synchronize_rcu(); + return 0; } EXPORT_SYMBOL(amd_iommu_register_ga_log_notifier);