RE: [PATCH V15 06/14] drm/xe: Guard teardown paths against purged BOs

> -----Original Message-----
> From: Ghimiray, Himal Prasad <[email protected]>
> Sent: 12 August 2026 08:54
> To: Upadhyay, Tejas <[email protected]>; intel-
> [email protected]
> Subject: Re: [PATCH V15 06/14] drm/xe: Guard teardown paths against
> purged BOs
> 
> 
> 
> On 11-08-2026 18:10, Tejas Upadhyay wrote:
> > VRAM page offlining can purge BOs that are still referenced by page
> > tables, exec queues, and DMA-buf exports. Add xe_bo_is_purged() guards
> > in the teardown paths to prevent unpinning or mapping an
> > already-purged BO:
> >
> > - xe_bo_unpin_map_no_vm(): skip unpin if purged
> > - xe_dma_buf_map(): return -ENOENT early if purged
> > - xe_exec_queue_update_run_ticks(): skip LRC timestamp read if purged
> > - xe_pt_destroy(): skip unpin if purged
> >
> > Signed-off-by: Tejas Upadhyay <[email protected]>
> > ---
> >   drivers/gpu/drm/xe/xe_bo.h         | 3 ++-
> >   drivers/gpu/drm/xe/xe_dma_buf.c    | 3 +++
> >   drivers/gpu/drm/xe/xe_exec_queue.c | 8 ++++++--
> >   drivers/gpu/drm/xe/xe_pt.c         | 3 ++-
> >   4 files changed, 13 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/xe/xe_bo.h b/drivers/gpu/drm/xe/xe_bo.h
> > index eede678ad303..dfcd0e57073b 100644
> > --- a/drivers/gpu/drm/xe/xe_bo.h
> > +++ b/drivers/gpu/drm/xe/xe_bo.h
> > @@ -364,7 +364,8 @@ static inline void xe_bo_unpin_map_no_vm(struct
> xe_bo *bo)
> >   {
> >   	if (likely(bo)) {
> >   		xe_bo_lock(bo, false);
> > -		xe_bo_unpin(bo);
> > +		if (!xe_bo_is_purged(bo))
> > +			xe_bo_unpin(bo);
> >   		xe_bo_unlock(bo);
> >
> >   		xe_bo_put(bo);
> > diff --git a/drivers/gpu/drm/xe/xe_dma_buf.c
> > b/drivers/gpu/drm/xe/xe_dma_buf.c index bf0728838ead..5d9f1cd24b7f
> > 100644
> > --- a/drivers/gpu/drm/xe/xe_dma_buf.c
> > +++ b/drivers/gpu/drm/xe/xe_dma_buf.c
> > @@ -104,6 +104,9 @@ static struct sg_table *xe_dma_buf_map(struct
> dma_buf_attachment *attach,
> >   	struct sg_table *sgt;
> >   	int r = 0;
> >
> > +	if (xe_bo_is_purged(bo))
> > +		return ERR_PTR(-ENOENT);
> > +
> >   	if (!attach->peer2peer && !xe_bo_can_migrate(bo, XE_PL_TT))
> >   		return ERR_PTR(-EOPNOTSUPP);
> >
> > diff --git a/drivers/gpu/drm/xe/xe_exec_queue.c
> > b/drivers/gpu/drm/xe/xe_exec_queue.c
> > index d6c7f346f49b..5432710c1cfb 100644
> > --- a/drivers/gpu/drm/xe/xe_exec_queue.c
> > +++ b/drivers/gpu/drm/xe/xe_exec_queue.c
> > @@ -1575,8 +1575,12 @@ void xe_exec_queue_update_run_ticks(struct
> xe_exec_queue *q)
> >   	 * errors.
> >   	 */
> >   	lrc = q->lrc[0];
> > -	new_ts = xe_lrc_update_timestamp(lrc, &old_ts);
> > -	q->xef->run_ticks[q->class] += (new_ts - old_ts) * q->width;
> > +	xe_bo_lock(lrc->bo, false);
> > +	if (!xe_bo_is_purged(lrc->bo)) {
> > +		new_ts = xe_lrc_update_timestamp(lrc, &old_ts);
> > +		q->xef->run_ticks[q->class] += (new_ts - old_ts) * q->width;
> > +	}
> > +	xe_bo_unlock(lrc->bo);
> >
> >   	drm_dev_exit(idx);
> >   }
> > diff --git a/drivers/gpu/drm/xe/xe_pt.c b/drivers/gpu/drm/xe/xe_pt.c
> > index 5d990c1c3740..dbf1aa26a21b 100644
> > --- a/drivers/gpu/drm/xe/xe_pt.c
> > +++ b/drivers/gpu/drm/xe/xe_pt.c
> > @@ -212,7 +212,8 @@ void xe_pt_destroy(struct xe_pt *pt, u32 flags,
> struct llist_head *deferred)
> >   		return;
> >
> >   	XE_WARN_ON(!list_empty(&pt->bo->ttm.base.gpuva.list));
> 
> no dma_resv lock ?

Ack, lock is needed. Will take care in next rev.

Tejas
> 
> > -	xe_bo_unpin(pt->bo);
> > +	if (!xe_bo_is_purged(pt->bo))
> > +		xe_bo_unpin(pt->bo);
> 
> >   	xe_bo_put_deferred(pt->bo, deferred);
> >
> >   	if (pt->level > 0 && pt->num_live) {