Re: [PATCH] x86: mark native_set_p4d() as __always_inline

[Kirill A. Shutemov]

On Tue, Jun 05, 2018 at 11:35:15AM +0000, Arnd Bergmann wrote:
> When CONFIG_OPTIMIZE_INLINING is enabled, the function native_set_p4d()
> may not be fully inlined into the caller, resulting in a false-positive
> warning about an access to the __pgtable_l5_enabled variable from a
> non-__init function, despite the original caller being an __init function:
> 
> WARNING: vmlinux.o(.text.unlikely+0x1429): Section mismatch in reference from the function native_set_p4d() to the variable .init.data:__pgtable_l5_enabled
> WARNING: vmlinux.o(.text.unlikely+0x1429): Section mismatch in reference from the function native_p4d_clear() to the variable .init.data:__pgtable_l5_enabled
> The function native_set_p4d() references
> the variable __initdata __pgtable_l5_enabled.
> This is often because native_set_p4d lacks a __initdata
> annotation or the annotation of __pgtable_l5_enabled is wrong.
> 
> Marking the native_set_p4d function and its caller native_p4d_clear()
> avoids this problem.
> 
> I did not bisect the original cause, but I assume this is related to
> the recent rework that turned pgtable_l5_enabled() into an inline
> function, which in turn caused the compiler to make different inlining
> decisions.
> 
> Fixes: ad3fe525b950 ("x86/mm: Unify pgtable_l5_enabled usage in early boot code")
> Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>

Thanks for fixing this.

Acked-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>

Do you have a clue which native_set_p4d() call causes the issue?

-- 
 Kirill A. Shutemov