From: Wei Fu <fuweid89@gmail.com>
To: ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org,
kafai@fb.com, songliubraving@fb.com, yhs@fb.com,
john.fastabend@gmail.com, kpsingh@kernel.org
Cc: bpf@vger.kernel.org, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org, Wei Fu <fuweid89@gmail.com>
Subject: [PATCH bpf] tools/bpf: only set obj->skeleton without err
Date: Sat, 8 Jan 2022 16:40:08 +0800 [thread overview]
Message-ID: <20220108084008.1053111-1-fuweid89@gmail.com> (raw)
After `bpftool gen skeleton`, the ${bpf_app}.skel.h will provide that
${bpf_app_name}__open helper to load bpf. If there is some error
like ENOMEM, the ${bpf_app_name}__open will rollback(free) the allocated
object, including `bpf_object_skeleton`.
Since the ${bpf_app_name}__create_skeleton set the obj->skeleton first
and not rollback it when error, it will cause double-free in
${bpf_app_name}__destory at ${bpf_app_name}__open. Therefore, we should
set the obj->skeleton before return 0;
Signed-off-by: Wei Fu <fuweid89@gmail.com>
---
tools/bpf/bpftool/gen.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/tools/bpf/bpftool/gen.c b/tools/bpf/bpftool/gen.c
index 5c18351290f0..e61e08f524da 100644
--- a/tools/bpf/bpftool/gen.c
+++ b/tools/bpf/bpftool/gen.c
@@ -928,7 +928,6 @@ static int do_skeleton(int argc, char **argv)
s = (struct bpf_object_skeleton *)calloc(1, sizeof(*s));\n\
if (!s) \n\
goto err; \n\
- obj->skeleton = s; \n\
\n\
s->sz = sizeof(*s); \n\
s->name = \"%1$s\"; \n\
@@ -1001,6 +1000,8 @@ static int do_skeleton(int argc, char **argv)
\n\
s->data = (void *)%2$s__elf_bytes(&s->data_sz); \n\
\n\
+ obj->skeleton = s; \n\
+ \n\
return 0; \n\
err: \n\
bpf_object__destroy_skeleton(s); \n\
--
2.25.1
next reply other threads:[~2022-01-08 8:40 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-08 8:40 Wei Fu [this message]
2022-01-10 2:04 ` [PATCH bpf] tools/bpf: only set obj->skeleton without err Andrii Nakryiko
2022-01-11 17:09 ` Wei Fu
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