On Thu, 2 May 2019 at 17:03, Martin Lau <kafai@xxxxxx> wrote: > > On Thu, May 02, 2019 at 11:49:32AM -0400, Lorenz Bauer wrote: > > Currently, code like the following segfaults if bpf_prog_load_xattr > > returns an error: > > > > struct bpf_object *obj; > > > > err = bpf_prog_load_xattr(&attr, &obj, &prog_fd); > > bpf_object__close(obj); > This is a bug. err should always be checked first before > using obj or prog_fd. If there is err, calling bpf_object__close(NULL) > is another redundancy. Ack, I'll send another patch. The bug is in a couple of places, so I figured that this is something people do naturally. > > > if (err) > > ... > > > > Unconditionally reset pobj to NULL at the start of the function > > to fix this. > Hence, this change is unnecessary. > > > > > Signed-off-by: Lorenz Bauer <lmb@xxxxxxxxxxxxxx> > > --- > > tools/lib/bpf/libbpf.c | 2 ++ > > 1 file changed, 2 insertions(+) > > > > diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c > > index 11a65db4b93f..2ddf3212b8f7 100644 > > --- a/tools/lib/bpf/libbpf.c > > +++ b/tools/lib/bpf/libbpf.c > > @@ -3363,6 +3363,8 @@ int bpf_prog_load_xattr(const struct bpf_prog_load_attr *attr, > > struct bpf_map *map; > > int err; > > > > + *pobj = NULL; > > + > > if (!attr) > > return -EINVAL; > > if (!attr->file) > > -- > > 2.19.1 > > -- Lorenz Bauer | Systems Engineer 25 Lavington St., London SE1 0NZ www.cloudflare.com
