Commit 1d489151e9f9d1647110277ff77282fe4d96d09b upstream.
Thanks to a recent binutils change which doesn't generate unused symbols, it's now possible for thunk_64.o be completely empty without 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 natechancellor@gmail.com Reviewed-by: Nathan Chancellor natechancellor@gmail.com Reviewed-by: Miroslav Benes mbenes@suse.cz Tested-by: Nathan Chancellor natechancellor@gmail.com Link: https://github.com/ClangBuiltLinux/linux/issues/1254 Signed-off-by: Josh Poimboeuf jpoimboe@redhat.com ---
This fixes a build break caused by the most recent version of binutils (2.36).
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 4e1d7460574b..9452cfb01ef1 100644 --- a/tools/objtool/elf.c +++ b/tools/objtool/elf.c @@ -354,8 +354,11 @@ 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");