4.4-stable review patch. If anyone has any objections, please let me know.
------------------ From: Martin Wilck <[email protected]> commit 25cad69f21f5532d99e2ee73c8ab6512bcab614c upstream. Since b8b2c7d845d5, platform_drv_probe() is called for all platform devices. If drv->probe is NULL, and dev_pm_domain_attach() fails, platform_drv_probe() will return the error code from dev_pm_domain_attach(). This causes real_probe() to enter the "probe_failed" path and set dev->driver to NULL. Before b8b2c7d845d5, real_probe() would assume success if both dev->bus->probe and drv->probe were missing. As a result, a device and driver could be "bound" together just by matching their names; this doesn't work any more after b8b2c7d845d5. This may cause problems later for certain usage of platform_driver_register() and platform_device_register_simple(). I observed a panic while loading the tpm_tis driver with parameter "force=1" (i.e. registering tpm_tis as a platform driver), because tpm_tis_init's assumption that the device returned by platform_device_register_simple() was bound didn't hold any more (tpmm_chip_alloc() dereferences chip->pdev->driver, causing panic). This patch restores the previous (4.3.0 and earlier) behavior of platform_drv_probe() in the case when the associated platform driver has no "probe" function. Fixes: b8b2c7d845d5 ("base/platform: assert that dev_pm_domain callbacks are called unconditionally") Signed-off-by: Martin Wilck <[email protected]> Cc: Martin Fuzzey <[email protected]> Acked-by: Jarkko Sakkinen <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- drivers/base/platform.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) --- a/drivers/base/platform.c +++ b/drivers/base/platform.c @@ -513,10 +513,15 @@ static int platform_drv_probe(struct dev return ret; ret = dev_pm_domain_attach(_dev, true); - if (ret != -EPROBE_DEFER && drv->probe) { - ret = drv->probe(dev); - if (ret) - dev_pm_domain_detach(_dev, true); + if (ret != -EPROBE_DEFER) { + if (drv->probe) { + ret = drv->probe(dev); + if (ret) + dev_pm_domain_detach(_dev, true); + } else { + /* don't fail if just dev_pm_domain_attach failed */ + ret = 0; + } } if (drv->prevent_deferred_probe && ret == -EPROBE_DEFER) {
