From 902baf61adf6b187f0a6b789e70d788ea71ff5bc Mon Sep 17 00:00:00 2001 From: Jacob Pan Date: Thu, 19 Mar 2020 21:32:30 -0700 Subject: iommu/vt-d: Fix mm reference leak Move canonical address check before mmget_not_zero() to avoid mm reference leak. Fixes: 9d8c3af31607 ("iommu/vt-d: IOMMU Page Request needs to check if address is canonical.") Signed-off-by: Jacob Pan Acked-by: Lu Baolu Signed-off-by: Joerg Roedel --- drivers/iommu/intel-svm.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) (limited to 'drivers/iommu') diff --git a/drivers/iommu/intel-svm.c b/drivers/iommu/intel-svm.c index d7f2a5358900..fc7d78876e02 100644 --- a/drivers/iommu/intel-svm.c +++ b/drivers/iommu/intel-svm.c @@ -611,14 +611,15 @@ static irqreturn_t prq_event_thread(int irq, void *d) * any faults on kernel addresses. */ if (!svm->mm) goto bad_req; - /* If the mm is already defunct, don't handle faults. */ - if (!mmget_not_zero(svm->mm)) - goto bad_req; /* If address is not canonical, return invalid response */ if (!is_canonical_address(address)) goto bad_req; + /* If the mm is already defunct, don't handle faults. */ + if (!mmget_not_zero(svm->mm)) + goto bad_req; + down_read(&svm->mm->mmap_sem); vma = find_extend_vma(svm->mm, address); if (!vma || address < vma->vm_start) -- cgit