From aeaacc3001449d44b4ab7da56331121d1f3b137b Mon Sep 17 00:00:00 2001 From: Fan Wu Date: Thu, 16 Jul 2026 11:32:30 +0000 Subject: [PATCH] media: ti: vpe: quiesce overflow recovery before freeing streams The VIP overflow recovery worker is armed from the hardirq handler when a FIFO overflow is detected, and the list-complete path looks the stream up through the VPDMA list private pointer. Both keep touching stream, port and device state; the recovery worker also resets the parser and VPDMA, repopulates the descriptor list, and re-enables the per-list IRQs. vip_stop_streaming() masks and clears the per-list IRQs, but it neither synchronizes the hardirq handler nor disables recovery_work. An overflow IRQ that has already queued recovery_work, or a list-complete IRQ in flight when the stream is torn down, can therefore still dereference the stream after its resources are released: the descriptor list is freed by vip_release_stream() on file release, and the stream itself by free_stream() on unbind/remove. Drain the recovery worker and the IRQ handler at both teardown points through a shared vip_quiesce_stream() helper, before any stream-owned resource is released. disable_work_sync() cancels pending recovery_work, drains a running instance, and raises its disable depth, so a subsequent schedule_work() issued by a racing IRQ handler is rejected at the workqueue scheduler: recovery_work cannot be requeued after disable_work_sync() takes effect. The worker may still re-enable the per-list IRQs before disable_work_sync() returns; disable_irqs() then masks those sources and synchronize_irq() waits for any in-flight handler that still dereferences stream state. In vip_stop_streaming() the helper runs before the parser is stopped, since a worker drained by disable_work_sync() may re-enable the parser before exiting and would otherwise undo the stop. recovery_work is created disabled and enabled in vip_start_streaming() before IRQs, pairing the enable with the teardown disable across the streaming lifecycle. This issue was found by an in-house static analysis tool and confirmed by manual code review. Fixes: fc2873aa4a21 ("media: ti: vpe: Add the VIP driver") Cc: stable@vger.kernel.org Assisted-by: Codex:gpt-5.6 Signed-off-by: Fan Wu Reviewed-by: Yemike Abhilash Chandra Tested-by: Yemike Abhilash Chandra Signed-off-by: Hans Verkuil --- drivers/media/platform/ti/vpe/vip.c | 37 +++++++++++++++++++++++++---- 1 file changed, 33 insertions(+), 4 deletions(-) diff --git a/drivers/media/platform/ti/vpe/vip.c b/drivers/media/platform/ti/vpe/vip.c index e56a95f53ea9..ccb688f4d7af 100644 --- a/drivers/media/platform/ti/vpe/vip.c +++ b/drivers/media/platform/ti/vpe/vip.c @@ -815,6 +815,22 @@ static void clear_irqs(struct vip_dev *dev, int irq_num, int list_num) vpdma_clear_list_stat(dev->shared->vpdma, irq_num, dev->slice_id); } +/* + * Quiesce recovery work and per-list IRQs before releasing stream resources. + * disable_work_sync() prevents the overflow handler from requeueing recovery + * work. Mask and synchronize IRQs afterwards because a running worker may + * have re-enabled them before exiting. + */ +static void vip_quiesce_stream(struct vip_stream *stream) +{ + struct vip_dev *dev = stream->port->dev; + + disable_work_sync(&stream->recovery_work); + disable_irqs(dev, dev->slice_id, stream->list_num); + clear_irqs(dev, dev->slice_id, stream->list_num); + synchronize_irq(dev->irq); +} + static void populate_desc_list(struct vip_stream *stream) { struct vip_port *port = stream->port; @@ -2429,6 +2445,7 @@ static int vip_start_streaming(struct vb2_queue *vq, unsigned int count) goto err; stream->num_recovery = 0; + enable_work(&stream->recovery_work); clear_irqs(dev, dev->slice_id, stream->list_num); enable_irqs(dev, dev->slice_id, stream->list_num); @@ -2453,13 +2470,17 @@ static void vip_stop_streaming(struct vb2_queue *vq) struct vip_dev *dev = port->dev; int ret; + /* + * A running recovery worker may re-enable the parser, so quiesce it + * and its IRQ handler before stopping the parser or releasing the + * descriptor list. + */ + vip_quiesce_stream(stream); + vip_parser_stop_imm(port, true); vip_enable_parser(port, false); unset_fmt_params(stream); - disable_irqs(dev, dev->slice_id, stream->list_num); - clear_irqs(dev, dev->slice_id, stream->list_num); - if (port->subdev) { ret = v4l2_subdev_call(port->subdev, video, s_stream, 0); if (ret) @@ -3075,6 +3096,8 @@ static int alloc_stream(struct vip_port *port, int stream_id, int vfl_type) goto do_free_hwlist; INIT_WORK(&stream->recovery_work, vip_overflow_recovery_work); + /* Start disabled; vip_start_streaming() enables it before IRQs. */ + disable_work(&stream->recovery_work); INIT_LIST_HEAD(&stream->vidq); @@ -3140,6 +3163,13 @@ static void free_stream(struct vip_stream *stream) return; dev = stream->port->dev; + /* + * Quiesce the IRQ handler and recovery worker, then drop the stream + * from cap_streams[], before releasing stream-owned resources. + */ + vip_quiesce_stream(stream); + stream->port->cap_streams[stream->stream_id] = NULL; + /* Free up the Drop queue */ list_for_each_safe(pos, q, &stream->dropq) { buf = list_entry(pos, @@ -3151,7 +3181,6 @@ static void free_stream(struct vip_stream *stream) video_unregister_device(stream->vfd); vpdma_hwlist_release(dev->shared->vpdma, stream->list_num); - stream->port->cap_streams[stream->stream_id] = NULL; kfree(stream); }