On Tue, Mar 11, 2025 at 3:40 PM Ard Biesheuvel <ardb@xxxxxxxxxx> wrote: > > On Tue, 11 Mar 2025 at 03:39, Masahiro Yamada <masahiroy@xxxxxxxxxx> wrote: > > > > On Sun, Mar 9, 2025 at 6:48 PM Ingo Molnar <mingo@xxxxxxxxxx> wrote: > > > > > > > > > * Ard Biesheuvel <ardb@xxxxxxxxxx> wrote: > > > > > > > On Sat, 8 Mar 2025 at 17:17, Masahiro Yamada <masahiroy@xxxxxxxxxx> wrote: > > > > > > > > > ... > > > > > I do not think it is broken. > > > > > As I mentioned above, I regard vmlinux.relocs as a byproduct > > > > > of the atomic build rule of vmlinux. This works. > > > > > > Except when it doesn't work, such as when an intermediate linking step > > > fails, and intermediate build products are lost and cannot be recreated > > > easily (or at all without modifying the source)? > > > > > > And the thing is, there should be no such thing as an 'atomic build > > > rule of vmlinux' if it means lost information when the build is broken > > > at an intermediate step. What purpose does it have? > > > > > > > There is no make rule for vmlinux.relocs, and so > > > > > > > > - if it gets deleted, it cannot be rebuilt and even though the build > > > > does not break, the relocation data is missing from the compressed > > > > image, and this could potentially break the kaslr startup code, > > > > - it vmlinux.relocs is older than vmlinux for some reason, make will > > > > not notice and silently reuse the outdated version, > > > > - when creating vmlinux.relocs from vmlinux and an error occurs, > > > > vmlinux is deleted, making it difficult to diagnose the problem. > > > > > > > > I think this is badly broken, but if you think this is all working as > > > > it should, I am not going to debate this further, and you can consider > > > > the patch series withdrawn. > > > > > > That's very sad, as both the simplification is substantial: > > > > > > 19 files changed, 52 insertions(+), 87 deletions(-) > > > > > > and the increase in debuggability is substantial as well. > > > > > > Thanks, > > > > > > Ingo > > > > When a byproduct is accidentally lost > > (for example, manually deleted), it is not automatically restored. > > Running 'rm vmlinux' or 'make clean' is needed. > > > > Exactly. Make cannot detect this situation, and so the build breaks in some way. > > > vmlinux.relocs is one such byproduct. > > Another is the map file when CONFIG_VMLINUX_MAP=y is enabled. > > > > The linker map is not depended upon by other build targets, and is > typically for human debug consumption, so while not ideal, it is not > as broken as for the unstripped vmlinux. Now you learned this statement is wrong. -- Best Regards Masahiro Yamada
