On 2020/3/20 12:32, Jacob Pan wrote:
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 <jacob.jun....@linux.intel.com>
Acked-by: Lu Baolu <baolu...@linux.intel.com> Best regards, baolu
--- drivers/iommu/intel-svm.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/drivers/iommu/intel-svm.c b/drivers/iommu/intel-svm.c index 1483f1845762..56253c59ca10 100644 --- a/drivers/iommu/intel-svm.c +++ b/drivers/iommu/intel-svm.c @@ -861,14 +861,15 @@ 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)
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