On Thu, Jan 14, 2021 at 04:24:15PM -0600, Josh Poimboeuf wrote: > Thanks to a recent binutils change which doesn't generate unused > symbols, it's now possible for thunk_64.o be completely empty with > CONFIG_PREEMPTION: no text, no data, no symbols. > > We could edit the Makefile to only build that file when > CONFIG_PREEMPTION is enabled, but that will likely create confusion > if/when the thunks end up getting used by some other code again. > > Just ignore it and move on. > > Reported-by: Nathan Chancellor <[email protected]> > Signed-off-by: Josh Poimboeuf <[email protected]>
Thanks for the quick fix! Reviewed-by: Nathan Chancellor <[email protected]> Tested-by: Nathan Chancellor <[email protected]> Is it worth a cc to stable given that I hit this in 5.4? I suppose it is not super critical now but it seems like someone might eventually hit this as times goes on and binutils 2.37 becomes more common. > --- > tools/objtool/elf.c | 7 +++++-- > 1 file changed, 5 insertions(+), 2 deletions(-) > > diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c > index be89c741ba9a..2b0f4f52f7b5 100644 > --- a/tools/objtool/elf.c > +++ b/tools/objtool/elf.c > @@ -380,8 +380,11 @@ static int read_symbols(struct elf *elf) > > symtab = find_section_by_name(elf, ".symtab"); > if (!symtab) { > - WARN("missing symbol table"); > - return -1; > + /* > + * A missing symbol table is actually possible if it's an empty > + * .o file. This can happen for thunk_64.o. > + */ > + return 0; > } > > symtab_shndx = find_section_by_name(elf, ".symtab_shndx"); > -- > 2.29.2 >
