Re: [PATCH] btf_encoder: Add extra checks for symbol names

[Arnaldo Carvalho de Melo <acme@kernel.org>]

Em Tue, Jan 12, 2021 at 04:27:59PM -0800, Tom Stellard escreveu:
> On 1/12/21 10:40 AM, Jiri Olsa wrote:
> > When processing kernel image build by clang we can
> > find some functions without the name, which causes
> > pahole to segfault.
> > 
> > Adding extra checks to make sure we always have
> > function's name defined before using it.
> > 
> 
> I backported this patch to pahole 1.19, and I can confirm it fixes the
> segfault for me.

I'm applying v2 for this patch and based on your above statement I'm
adding a:

Tested-by: Tom Stellard <tstellar@redhat.com>

Ok?

Who originally reported this?

- Arnaldo
 
> -Tom
> 
> > Signed-off-by: Jiri Olsa <jolsa@kernel.org>
> > ---
> >   btf_encoder.c | 8 ++++++--
> >   1 file changed, 6 insertions(+), 2 deletions(-)
> > 
> > diff --git a/btf_encoder.c b/btf_encoder.c
> > index 333973054b61..17f7a14f2ef0 100644
> > --- a/btf_encoder.c
> > +++ b/btf_encoder.c
> > @@ -72,6 +72,8 @@ static int collect_function(struct btf_elf *btfe, GElf_Sym *sym)
> >   	if (elf_sym__type(sym) != STT_FUNC)
> >   		return 0;
> > +	if (!elf_sym__name(sym, btfe->symtab))
> > +		return 0;
> >   	if (functions_cnt == functions_alloc) {
> >   		functions_alloc = max(1000, functions_alloc * 3 / 2);
> > @@ -730,9 +732,11 @@ int cu__encode_btf(struct cu *cu, int verbose, bool force,
> >   		if (!has_arg_names(cu, &fn->proto))
> >   			continue;
> >   		if (functions_cnt) {
> > -			struct elf_function *func;
> > +			const char *name = function__name(fn, cu);
> > +			struct elf_function *func = NULL;
> > -			func = find_function(btfe, function__name(fn, cu));
> > +			if (name)
> > +				func = find_function(btfe, name);
> >   			if (!func || func->generated)
> >   				continue;
> >   			func->generated = true;
> > 
> 

-- 

- Arnaldo