[PATCH v5 1/3] driver-core: return EINVAL error instead of BUG_ON()

From: Florian Schmaus
Date: Wed May 16 2018 - 11:35:57 EST


I triggerd the BUG_ON() in driver_register() when booting a domU Xen
domain. Since there was no contextual information logged, I needed to
attach kgdb to determine the culprit (the wmi-bmof driver in my
case). The BUG_ON() was added in commit f48f3febb2cb ("driver-core: do
not register a driver with bus_type not registered").

Instead of running into a BUG_ON() we print an error message
identifying the, likely faulty, driver but continue booting.

Signed-off-by: Florian Schmaus <flo@xxxxxxxxxxxx>
---

Notes:
- Do not split long strings across lines.

drivers/base/driver.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/base/driver.c b/drivers/base/driver.c
index ba912558a510..16b81d1c6cb7 100644
--- a/drivers/base/driver.c
+++ b/drivers/base/driver.c
@@ -148,7 +148,11 @@ int driver_register(struct device_driver *drv)
int ret;
struct device_driver *other;

- BUG_ON(!drv->bus->p);
+ if (!drv->bus->p) {
+ pr_err("Driver '%s' was unable to register with bus_type '%s' because it was not initialized.\n",
+ drv->name, drv->bus->name);
+ return -EINVAL;
+ }

if ((drv->bus->probe && drv->probe) ||
(drv->bus->remove && drv->remove) ||
--
2.16.1