On Wed, Nov 03, 2021 at 03:34:05PM +0200, Sakari Ailus wrote: > Printk modifier %pfw is used to print the full path of the device name. > This is obtained device by device until a device no longer has a parent. > > On ACPI getting the parent fwnode is done by calling acpi_get_parent() > which tries to down() a semaphore. But local IRQs are now disabled in > vprintk_store() before the mutex is acquired. This is obviously a problem. > > Luckily struct acpi_device has a parent field already. Use that field to > get the parent instead of relying on acpi_get_parent(). I think the best if Rafael can confirm that we may use it like this. If he approved, nothing would stop me to give you Reviewed-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxx> > Fixes: 002eb6ad0751 ("printk: track/limit recursion") > Cc: stable@xxxxxxxxxxxxxxx # v5.15 and up > Depends-on: ("ACPI: Make acpi_fwnode_handle safer") > Signed-off-by: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx> > --- > drivers/acpi/property.c | 12 ++++-------- > 1 file changed, 4 insertions(+), 8 deletions(-) > > diff --git a/drivers/acpi/property.c b/drivers/acpi/property.c > index e312ebaed8db4..7403ee2816eb8 100644 > --- a/drivers/acpi/property.c > +++ b/drivers/acpi/property.c > @@ -1089,16 +1089,12 @@ struct fwnode_handle *acpi_node_get_parent(const struct fwnode_handle *fwnode) > if (is_acpi_data_node(fwnode)) { > /* All data nodes have parent pointer so just return that */ > return to_acpi_data_node(fwnode)->parent; > - } else if (is_acpi_device_node(fwnode)) { > - acpi_handle handle, parent_handle; > + } > > - handle = to_acpi_device_node(fwnode)->handle; > - if (ACPI_SUCCESS(acpi_get_parent(handle, &parent_handle))) { > - struct acpi_device *adev; > + if (is_acpi_device_node(fwnode)) { > + struct acpi_device *device = to_acpi_device_node(fwnode); > > - if (!acpi_bus_get_device(parent_handle, &adev)) > - return acpi_fwnode_handle(adev); > - } > + return acpi_fwnode_handle(device->parent); > } > > return NULL; > -- > 2.30.2 > > -- With Best Regards, Andy Shevchenko