4.9-stable review patch. If anyone has any objections, please let me know.
------------------ From: Pan Bian <[email protected]> commit 73dbd4a4230216b6a5540a362edceae0c9b4876b upstream. In function amd_iommu_bind_pasid(), the control flow jumps to label out_free when pasid_state->mm and mm is NULL. And mmput(mm) is called. In function mmput(mm), mm is referenced without validation. This will result in a NULL dereference bug. This patch fixes the bug. Signed-off-by: Pan Bian <[email protected]> Fixes: f0aac63b873b ('iommu/amd: Don't hold a reference to mm_struct') Signed-off-by: Joerg Roedel <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- drivers/iommu/amd_iommu_v2.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/drivers/iommu/amd_iommu_v2.c +++ b/drivers/iommu/amd_iommu_v2.c @@ -695,9 +695,9 @@ out_clear_state: out_unregister: mmu_notifier_unregister(&pasid_state->mn, mm); + mmput(mm); out_free: - mmput(mm); free_pasid_state(pasid_state); out:
