On Tue, Mar 9, 2021 at 10:43 PM Kees Cook <keescook@xxxxxxxxxxxx> wrote: > > Right now, the state of CONFIG_INIT_ON_ALLOC_DEFAULT_ON (and > ...ON_FREE...) did not change the assembly ordering of the static branch > tests. Use the new jump_label macro to check CONFIG settings to default > to the "expected" state, unpessimizes the resulting assembly code. > > Reviewed-by: Alexander Potapenko <glider@xxxxxxxxxx> > Link: https://lore.kernel.org/lkml/CAG_fn=X0DVwqLaHJTO6Jw7TGcMSm77GKHinrd0m_6y0SzWOrFA@xxxxxxxxxxxxxx/ > Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx> > --- > include/linux/mm.h | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/include/linux/mm.h b/include/linux/mm.h > index bf341a9bfe46..2ccd856ac0d1 100644 > --- a/include/linux/mm.h > +++ b/include/linux/mm.h > @@ -2874,7 +2874,8 @@ static inline void kernel_unpoison_pages(struct page *page, int numpages) { } > DECLARE_STATIC_KEY_MAYBE(CONFIG_INIT_ON_ALLOC_DEFAULT_ON, init_on_alloc); > static inline bool want_init_on_alloc(gfp_t flags) > { > - if (static_branch_unlikely(&init_on_alloc)) > + if (static_branch_maybe(CONFIG_INIT_ON_ALLOC_DEFAULT_ON, > + &init_on_alloc)) > return true; > return flags & __GFP_ZERO; > } > @@ -2882,7 +2883,8 @@ static inline bool want_init_on_alloc(gfp_t flags) > DECLARE_STATIC_KEY_MAYBE(CONFIG_INIT_ON_FREE_DEFAULT_ON, init_on_free); > static inline bool want_init_on_free(void) > { > - return static_branch_unlikely(&init_on_free); > + return static_branch_maybe(CONFIG_INIT_ON_FREE_DEFAULT_ON, > + &init_on_free); > } > > extern bool _debug_pagealloc_enabled_early; Should we also update slab_want_init_on_alloc() and slab_want_init_on_free()?
