Messages in this thread | | | Date | Thu, 27 Oct 2022 16:08:22 +0200 | From | "Arnd Bergmann" <> | Subject | Re: [PATCH] staging: vchiq: add 'static' to function definition |
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On Sat, Oct 22, 2022, at 10:07, Greg Kroah-Hartman wrote: > On Sat, Oct 22, 2022 at 03:35:48PM +1100, Scott J. Crouch wrote:
> Nice try, but this breaks the build in a very horrible and strange way > that no one has been able to figure out yet:
I got curious and figured out what happens:
Without CONFIG_OF, of_match_node() always returns NULL, so vchiq_probe() returns -EINVAL unconditionally before calling vchiq_platform_init().
If vchiq_platform_init() is marked 'static', gcc's dead code elimination then eliminates it, which in turn means that 'g_fragments_base' is never initialized and gets replaced with a NULL pointer.
I think the easiest workaround is to take this otherwise correct patch but at the same time add 'depends on OF' to BCM2835_VCHIQ. This is a correct dependency as shown by gcc above, and it still allows compile testing this driver on x86 allmodconfig, which enables CONFIG_OF.
Arnd
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