diff options
author | Andrii Nakryiko <andrii@kernel.org> | 2020-11-06 16:02:51 -0800 |
---|---|---|
committer | Daniel Borkmann <daniel@iogearbox.net> | 2020-11-09 22:15:23 +0100 |
commit | 197afc631413d96dc60acfc7970bdd4125d38cd3 (patch) | |
tree | 18dfc01e3ad39fa1f38086fe854b0986ecaa01dd /tools/testing/selftests | |
parent | 4e0396c59559264442963b349ab71f66e471f84d (diff) |
libbpf: Don't attempt to load unused subprog as an entry-point BPF program
If BPF code contains unused BPF subprogram and there are no other subprogram
calls (which can realistically happen in real-world applications given
sufficiently smart Clang code optimizations), libbpf will erroneously assume
that subprograms are entry-point programs and will attempt to load them with
UNSPEC program type.
Fix by not relying on subcall instructions and rather detect it based on the
structure of BPF object's sections.
Fixes: 9a94f277c4fb ("tools: libbpf: restore the ability to load programs from .text section")
Reported-by: Dmitrii Banshchikov <dbanschikov@fb.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20201107000251.256821-1-andrii@kernel.org
Diffstat (limited to 'tools/testing/selftests')
-rw-r--r-- | tools/testing/selftests/bpf/prog_tests/subprogs.c | 6 | ||||
-rw-r--r-- | tools/testing/selftests/bpf/progs/test_subprogs_unused.c | 21 |
2 files changed, 27 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/prog_tests/subprogs.c b/tools/testing/selftests/bpf/prog_tests/subprogs.c index a00abf58c037..3f3d2ac4dd57 100644 --- a/tools/testing/selftests/bpf/prog_tests/subprogs.c +++ b/tools/testing/selftests/bpf/prog_tests/subprogs.c @@ -3,12 +3,14 @@ #include <test_progs.h> #include <time.h> #include "test_subprogs.skel.h" +#include "test_subprogs_unused.skel.h" static int duration; void test_subprogs(void) { struct test_subprogs *skel; + struct test_subprogs_unused *skel2; int err; skel = test_subprogs__open_and_load(); @@ -26,6 +28,10 @@ void test_subprogs(void) CHECK(skel->bss->res3 != 19, "res3", "got %d, exp %d\n", skel->bss->res3, 19); CHECK(skel->bss->res4 != 36, "res4", "got %d, exp %d\n", skel->bss->res4, 36); + skel2 = test_subprogs_unused__open_and_load(); + ASSERT_OK_PTR(skel2, "unused_progs_skel"); + test_subprogs_unused__destroy(skel2); + cleanup: test_subprogs__destroy(skel); } diff --git a/tools/testing/selftests/bpf/progs/test_subprogs_unused.c b/tools/testing/selftests/bpf/progs/test_subprogs_unused.c new file mode 100644 index 000000000000..75d975f8cf90 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/test_subprogs_unused.c @@ -0,0 +1,21 @@ +#include "vmlinux.h" +#include <bpf/bpf_helpers.h> +#include <bpf/bpf_core_read.h> + +const char LICENSE[] SEC("license") = "GPL"; + +__attribute__((maybe_unused)) __noinline int unused1(int x) +{ + return x + 1; +} + +static __attribute__((maybe_unused)) __noinline int unused2(int x) +{ + return x + 2; +} + +SEC("raw_tp/sys_enter") +int main_prog(void *ctx) +{ + return 0; +} |