On Tue, Apr 02, 2024 at 07:35:45PM -0400, Peter Xu wrote: > On Tue, Apr 02, 2024 at 07:53:20PM -0300, Jason Gunthorpe wrote: > > On Tue, Apr 02, 2024 at 06:43:56PM -0400, Peter Xu wrote: > > > > > I actually tested this without hitting the issue (even though I didn't > > > mention it in the cover letter..). I re-kicked the build test, it turns > > > out my "make alldefconfig" on loongarch will generate a config with both > > > HUGETLB=n && THP=n, while arch/loongarch/configs/loongson3_defconfig has > > > THP=y (which I assume was the one above build used). I didn't further > > > check how "make alldefconfig" generated the config; a bit surprising that > > > it didn't fetch from there. > > > > I suspect it is weird compiler variations.. Maybe something is not > > being inlined. > > > > > (and it also surprises me that this BUILD_BUG can trigger.. I used to try > > > triggering it elsewhere but failed..) > > > > As the pud_leaf() == FALSE should result in the BUILD_BUG never being > > called and the optimizer removing it. > > Good point, for some reason loongarch defined pud_leaf() without defining > pud_pfn(), which does look strange. > > #define pud_leaf(pud) ((pud_val(pud) & _PAGE_HUGE) != 0) > > But I noticed at least MIPS also does it.. Logically I think one arch > should define either none of both. Wow, this is definately an arch issue. You can't define pud_leaf() and not have a pud_pfn(). It makes no sense at all.. I'd say the BUILD_BUG has done it's job and found an issue, fix it by not defining pud_leaf? I don't see any calls to pud_leaf in loongarch at least Jason
