The vm pointer returned from amdgpu_vm_get_vm_from_pasid() is only valid while the lock is still being held. Once xa_unlock_irqrestore is called and returned, the pointer is no longer under lock and is subject to modification. Since, the caller still dereferences vm->task_info in amdgpu_vm_get_task_info_vm() after the lock is removed, this causes a use after unlock problem.
Remove the lifetime issue present in amdgpu_vm_get_task_info_pasid() through removing the amdgpu_vm_get_vm_from_pasid() function from amdgpu_vm.c and making the relevant code inline to hold the lock while it is still in use. Signed-off-by: Shahyan Soltani <[email protected]> --- drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c | 25 ++++++++++--------------- 1 file changed, 10 insertions(+), 15 deletions(-) diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c index 32719f31b6c9..180d694323e8 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c @@ -2460,19 +2460,6 @@ static void amdgpu_vm_destroy_task_info(struct kref *kref) kfree(ti); } -static inline struct amdgpu_vm * -amdgpu_vm_get_vm_from_pasid(struct amdgpu_device *adev, u32 pasid) -{ - struct amdgpu_vm *vm; - unsigned long flags; - - xa_lock_irqsave(&adev->vm_manager.pasids, flags); - vm = xa_load(&adev->vm_manager.pasids, pasid); - xa_unlock_irqrestore(&adev->vm_manager.pasids, flags); - - return vm; -} - /** * amdgpu_vm_put_task_info - reference down the vm task_info ptr * @@ -2519,8 +2506,16 @@ amdgpu_vm_get_task_info_vm(struct amdgpu_vm *vm) struct amdgpu_task_info * amdgpu_vm_get_task_info_pasid(struct amdgpu_device *adev, u32 pasid) { - return amdgpu_vm_get_task_info_vm( - amdgpu_vm_get_vm_from_pasid(adev, pasid)); + struct amdgpu_task_info *ti; + struct amdgpu_vm *vm; + unsigned long flags; + + xa_lock_irqsave(&adev->vm_manager.pasids, flags); + vm = xa_load(&adev->vm_manager.pasids, pasid); + ti = amdgpu_vm_get_task_info_vm(vm); + xa_unlock_irqrestore(&adev->vm_manager.pasids, flags); + + return ti; } static int amdgpu_vm_create_task_info(struct amdgpu_vm *vm) -- 2.54.0
