6.6-stable review patch. If anyone has any objections, please let me know.
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From: Lucas De Marchi lucas.demarchi@intel.com
[ Upstream commit 8e1ddfada4530939a8cb64ee9251aef780474274 ]
When releasing a device, if the release action causes a group to be released, a warning is emitted because it can't find the group. This happens because devres_release_all() moves the entire list to a todo list and also move the group markers. Considering r* normal resource nodes and g1 a group resource node:
g1 -----------. v v r1 -> r2 -> g1[0] -> r3-> g[1] -> r4
After devres_release_all(), dev->devres_head becomes empty and the todo list it iterates on becomes:
g1 v r1 -> r2 -> r3-> r4 -> g1[0]
When a call to component_del() is made and takes down the aggregate device, a warning like this happen:
RIP: 0010:devres_release_group+0x362/0x530 ... Call Trace: <TASK> component_unbind+0x156/0x380 component_unbind_all+0x1d0/0x270 mei_component_master_unbind+0x28/0x80 [mei_hdcp] take_down_aggregate_device+0xc1/0x160 component_del+0x1c6/0x3e0 intel_hdcp_component_fini+0xf1/0x170 [xe] xe_display_fini+0x1e/0x40 [xe]
Because the devres group corresponding to the hdcp component cannot be found. Just ignore this corner case: if the dev->devres_head is empty and the caller is trying to remove a group, it's likely in the process of device cleanup so just ignore it instead of warning.
Acked-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Reviewed-by: Rodrigo Vivi rodrigo.vivi@intel.com Link: https://patchwork.freedesktop.org/patch/msgid/20250222001051.3012936-2-lucas... Signed-off-by: Lucas De Marchi lucas.demarchi@intel.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/base/devres.c | 7 +++++++ 1 file changed, 7 insertions(+)
diff --git a/drivers/base/devres.c b/drivers/base/devres.c index e9b0d94aeabd9..8a0f000221271 100644 --- a/drivers/base/devres.c +++ b/drivers/base/devres.c @@ -687,6 +687,13 @@ int devres_release_group(struct device *dev, void *id) spin_unlock_irqrestore(&dev->devres_lock, flags);
release_nodes(dev, &todo); + } else if (list_empty(&dev->devres_head)) { + /* + * dev is probably dying via devres_release_all(): groups + * have already been removed and are on the process of + * being released - don't touch and don't warn. + */ + spin_unlock_irqrestore(&dev->devres_lock, flags); } else { WARN_ON(1); spin_unlock_irqrestore(&dev->devres_lock, flags);