staging: media: tegra-video: fix infinite recursion regression
Since commit9bf19fbf0c
("media: v4l: async: Rework internal lists"), aka v6.6-rc1~97^2~198, probing the tegra-video VI driver causes infinite recursion due tegra_vi_graph_parse_one() calling itself until: [ 1.571168] Insufficient stack space to handle exception! ... [ 1.591416] Internal error: kernel stack overflow: 0 [#1] PREEMPT SMP ARM ... [ 3.861013] of_phandle_iterator_init from __of_parse_phandle_with_args+0x40/0xf0 [ 3.868497] __of_parse_phandle_with_args from of_fwnode_graph_get_remote_endpoint+0x68/0xa8 [ 3.876938] of_fwnode_graph_get_remote_endpoint from fwnode_graph_get_remote_port_parent+0x30/0x7c [ 3.885984] fwnode_graph_get_remote_port_parent from tegra_vi_graph_parse_one+0x7c/0x224 [ 3.894158] tegra_vi_graph_parse_one from tegra_vi_graph_parse_one+0x144/0x224 [ 3.901459] tegra_vi_graph_parse_one from tegra_vi_graph_parse_one+0x144/0x224 [ 3.908760] tegra_vi_graph_parse_one from tegra_vi_graph_parse_one+0x144/0x224 [ 3.916061] tegra_vi_graph_parse_one from tegra_vi_graph_parse_one+0x144/0x224 ... [ 4.857892] tegra_vi_graph_parse_one from tegra_vi_graph_parse_one+0x144/0x224 [ 4.865193] tegra_vi_graph_parse_one from tegra_vi_graph_parse_one+0x144/0x224 [ 4.872494] tegra_vi_graph_parse_one from tegra_vi_init+0x574/0x6d4 [ 4.878842] tegra_vi_init from host1x_device_init+0x84/0x15c [ 4.884594] host1x_device_init from host1x_video_probe+0xa0/0x114 [ 4.890770] host1x_video_probe from really_probe+0xe0/0x400 The reason is the mentioned commit changed tegra_vi_graph_find_entity() to search for an entity in the done notifier list: > @@ -1464,7 +1464,7 @@ tegra_vi_graph_find_entity(struct tegra_vi_channel *chan, > struct tegra_vi_graph_entity *entity; > struct v4l2_async_connection *asd; > > - list_for_each_entry(asd, &chan->notifier.asc_list, asc_entry) { > + list_for_each_entry(asd, &chan->notifier.done_list, asc_entry) { > entity = to_tegra_vi_graph_entity(asd); > if (entity->asd.match.fwnode == fwnode) > return entity; This is not always correct, being tegra_vi_graph_find_entity() called in three locations, in this order: 1. tegra_vi_graph_parse_one() -- called while probing 2. tegra_vi_graph_notify_bound() -- the .bound notifier op 3. tegra_vi_graph_build() -- called in the .complete notifier op Locations 1 and 2 are called before moving the entity from waiting_list to done_list, thus they won't find what they are looking for in done_list. Location 3 happens afterwards and thus it is not broken, however it means tegra_vi_graph_find_entity() should not search in the same list every time. The error appears at step 1: tegra_vi_graph_parse_one() iterates recursively until it finds the entity already notified, which now never happens. Fix by passing the specific notifier list pointer to tegra_vi_graph_find_entity() instead of the channel, so each caller can search in whatever list is correct. Also improve the tegra_vi_graph_find_entity() comment. Fixes:9bf19fbf0c
("media: v4l: async: Rework internal lists") Cc: Thierry Reding <thierry.reding@gmail.com> Cc: Jonathan Hunter <jonathanh@nvidia.com> Cc: Sowjanya Komatineni <skomatineni@nvidia.com> Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com> [Sakari Ailus: Wrapped some long lines.] Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
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@ -1455,17 +1455,18 @@ static int __maybe_unused vi_runtime_suspend(struct device *dev)
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}
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/*
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* Graph Management
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* Find the entity matching a given fwnode in an v4l2_async_notifier list
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*/
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static struct tegra_vi_graph_entity *
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tegra_vi_graph_find_entity(struct tegra_vi_channel *chan,
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tegra_vi_graph_find_entity(struct list_head *list,
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const struct fwnode_handle *fwnode)
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{
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struct tegra_vi_graph_entity *entity;
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struct v4l2_async_connection *asd;
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list_for_each_entry(asd, &chan->notifier.done_list, asc_entry) {
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list_for_each_entry(asd, list, asc_entry) {
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entity = to_tegra_vi_graph_entity(asd);
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if (entity->asd.match.fwnode == fwnode)
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return entity;
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}
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@ -1532,7 +1533,8 @@ static int tegra_vi_graph_build(struct tegra_vi_channel *chan,
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}
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/* find the remote entity from notifier list */
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ent = tegra_vi_graph_find_entity(chan, link.remote_node);
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ent = tegra_vi_graph_find_entity(&chan->notifier.done_list,
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link.remote_node);
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if (!ent) {
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dev_err(vi->dev, "no entity found for %pOF\n",
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to_of_node(link.remote_node));
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@ -1664,7 +1666,8 @@ static int tegra_vi_graph_notify_bound(struct v4l2_async_notifier *notifier,
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* Locate the entity corresponding to the bound subdev and store the
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* subdev pointer.
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*/
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entity = tegra_vi_graph_find_entity(chan, subdev->fwnode);
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entity = tegra_vi_graph_find_entity(&chan->notifier.waiting_list,
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subdev->fwnode);
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if (!entity) {
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dev_err(vi->dev, "no entity for subdev %s\n", subdev->name);
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return -EINVAL;
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@ -1713,7 +1716,8 @@ static int tegra_vi_graph_parse_one(struct tegra_vi_channel *chan,
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/* skip entities that are already processed */
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if (device_match_fwnode(vi->dev, remote) ||
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tegra_vi_graph_find_entity(chan, remote)) {
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tegra_vi_graph_find_entity(&chan->notifier.waiting_list,
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remote)) {
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fwnode_handle_put(remote);
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continue;
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}
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