On 16/08/2018 12:04:13+0200, Greg Kroah-Hartman wrote: > On Thu, Aug 16, 2018 at 10:34:38AM +0200, Alexandre Belloni wrote: > > On 16/08/2018 10:01:12+0200, Greg Kroah-Hartman wrote: > > > On Thu, Aug 16, 2018 at 09:39:41AM +0200, Alexandre Belloni wrote: > > > > When both uio and the uio drivers are built in the kernel, it is > > > > possible > > > > for a driver to register devices before the uio class is registered. > > > > > > How does this happen? The link order should solve this issue, right? > > > > > > > Sure, if we can ensure uio_init() is called before any driver calls > > uio_register_device() then this would not happen. However, I'm not sure > > how you would want to achieve that. > > That is the job of the link order, does this not work properly today? > How have you triggered this so that you could test your patch? >
I have a (not yet upstreamed) MFD driver in drivers/mfd that is registering the uio device. It mostly look like uio_pci_generic.c. When compiling both as builtin, it will crash that way. There are no link dependency between uio_init and uio_register_device calls so I guess the linker can't reorder that properly. -- Alexandre Belloni, Bootlin Embedded Linux and Kernel engineering https://bootlin.com