On Wed, Dec 30, 2020 at 04:40:40PM +0100, Arnd Bergmann wrote: > From: Arnd Bergmann <[email protected]> > > clang cannt evaluate this function argument at compile time > when the function is not inlined, which leads to a link > time failure: > > ld.lld: error: undefined symbol: __compiletime_assert_414 > >>> referenced by mremap.c > >>> mremap.o:(get_extent) in archive mm/built-in.a > > Mark the function as __always_inline to avoid it. > > Fixes: 9ad9718bfa41 ("mm/mremap: calculate extent in one place") > Signed-off-by: Arnd Bergmann <[email protected]> > --- > mm/mremap.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/mm/mremap.c b/mm/mremap.c > index c5590afe7165..1cb464a07184 100644 > --- a/mm/mremap.c > +++ b/mm/mremap.c > @@ -336,8 +336,9 @@ enum pgt_entry { > * valid. Else returns a smaller extent bounded by the end of the source and > * destination pgt_entry. > */ > -static unsigned long get_extent(enum pgt_entry entry, unsigned long old_addr, > - unsigned long old_end, unsigned long new_addr) > +static __always_inline unsigned long get_extent(enum pgt_entry entry, > + unsigned long old_addr, unsigned long old_end, > + unsigned long new_addr) > { > unsigned long next, extent, mask, size; > > -- > 2.29.2 >
I am in agreement with Vlastimil, I would rather see the BUILD_BUG() dropped or converted into BUG() instead of papering over with __always_inline. For what it's worth, I only see this build failure with CONFIG_UBSAN_UNSIGNED_OVERFLOW, which you proposed disabling: https://lore.kernel.org/lkml/[email protected]/ Cheers, Nathan
