On Wed, Oct 21, 2020 at 1:09 PM Kees Cook <keescook@xxxxxxxxxxxx> wrote: > > On Wed, Oct 14, 2020 at 09:53:39PM -0700, Fāng-ruì Sòng wrote: > > On Wed, Oct 14, 2020 at 4:04 PM Kees Cook <keescook@xxxxxxxxxxxx> wrote: > > > > index 5430febd34be..b83c00c63997 100644 > > > > --- a/include/asm-generic/vmlinux.lds.h > > > > +++ b/include/asm-generic/vmlinux.lds.h > > > > @@ -684,6 +684,7 @@ > > > > #ifdef CONFIG_CONSTRUCTORS > > > > #define KERNEL_CTORS() . = ALIGN(8); \ > > > > __ctors_start = .; \ > > > > + KEEP(*(SORT(.ctors.*))) \ > > > > KEEP(*(.ctors)) \ > > > > KEEP(*(SORT(.init_array.*))) \ > > > > KEEP(*(.init_array)) \ > > > > -- > > > > 2.25.1 > > > > I think it would be great to figure out why these .ctors.* .dtors.* are generated. > > I haven't had the time to investigate. This patch keeps sfr's builds > from regressing, so we need at least this first. We need to know under what circumstances .ctors.* are generated. For Clang>=10.0.1, for all *-linux triples, .init_array/.finit_array are used by default. There is a toggle -fno-use-init-array (not in GCC) to switch back to .ctors/.dtors Modern GCC also uses .init_array. The minimum requirement is now GCC 4.9 and thus I wonder whether the .ctors configuration is still supported. If it is (maybe because glibc version which is not specified on https://www.kernel.org/doc/html/latest/process/changes.html ), we should use some #if to highlight that. > > ~GCC 4.7 switched to default to .init_array/.fini_array if libc > > supports it. I have some refactoring in this area of Clang as well > > (e.g. https://reviews.llvm.org/D71393) > > > > And I am not sure SORT(.init_array.*) or SORT(.ctors.*) will work. The > > correct construct is SORT_BY_INIT_PRIORITY(.init_array.*) > > The kernel doesn't seem to use the init_priority attribute at all. Are > you saying the cause of the .ctors.* names are a result of some internal > use of init_priority by the compiler here? > If no priority is intended, consider deleting SORT to avoid confusion?
