Re: [PATCH] init/main.c: check for null pointer before calling initcall

[Abderrahmane Benbachir]

David Daney <ddaney@xxxxxxxxxxxxxxxxxx> a ÃcritÂ:

> On 10/27/2017 11:22 AM, Thomas Gleixner wrote:
> > On Fri, 27 Oct 2017, David Daney wrote:
> >
> > > On 10/27/2017 09:47 AM, Abderrahmane Benbachir wrote:
> > > > Simple check to prevent kernel panic when initcall does not exit
> > >
> > > Interesting, under what circumstances do you observe the panic?
> > >
> > > It would be best to include this information in the patch changelog.
> >
> > device_initcall(NULL);
> >
> > might do that, but then it rightfully crashes on boot.
>
> That was kind of my point.  The module loader case already checks  
> for a non-NULL pointer, and any NULLs in the in-kernel initializer  
> tables would indicate a bigger problem that should be fixed instead.
>
> David Daney

But this code can still be written :

static initcall_t __initcall_mymod \
   __used __section(".initcall6.init") = NULL;

In fact, I'm using the code below to assign at runtime (dynamically) which
function to be executed or not.