>From c68f8e699a639392f24244068c1b49389f67f302 Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Thu, 9 Sep 2021 22:55:13 +0000 Subject: [PATCH bpf-next] bpf, selftests: Replicate tailcall_3 limit test for indirect call case The tailcall_3 test program uses bpf_tail_call_static() where the JIT would patch a direct jump. Add a new tailcall_6 test program replicating exactly the same test just ensuring that bpf_tail_call() uses a map index where the verifier cannot make assumptions this time. In other words this will now cover both on x86-64 JIT, emit_bpf_tail_call_direct() emission as well as emit_bpf_tail_call_indirect() emission. # ./test_progs -t tailcalls #136/1 tailcalls/tailcall_1:OK #136/2 tailcalls/tailcall_2:OK #136/3 tailcalls/tailcall_3:OK #136/4 tailcalls/tailcall_4:OK #136/5 tailcalls/tailcall_5:OK #136/6 tailcalls/tailcall_6:OK #136/7 tailcalls/tailcall_bpf2bpf_1:OK #136/8 tailcalls/tailcall_bpf2bpf_2:OK #136/9 tailcalls/tailcall_bpf2bpf_3:OK #136/10 tailcalls/tailcall_bpf2bpf_4:OK #136/11 tailcalls/tailcall_bpf2bpf_5:OK #136 tailcalls:OK Summary: 1/11 PASSED, 0 SKIPPED, 0 FAILED Signed-off-by: Daniel Borkmann Cc: Johan Almbladh Cc: Paul Chaignon Cc: Tiezhu Yang --- .../selftests/bpf/prog_tests/tailcalls.c | 25 ++++++++++--- tools/testing/selftests/bpf/progs/tailcall6.c | 36 +++++++++++++++++++ 2 files changed, 56 insertions(+), 5 deletions(-) create mode 100644 tools/testing/selftests/bpf/progs/tailcall6.c diff --git a/tools/testing/selftests/bpf/prog_tests/tailcalls.c b/tools/testing/selftests/bpf/prog_tests/tailcalls.c index b5940e6ca67c..7bf3a7a97d7b 100644 --- a/tools/testing/selftests/bpf/prog_tests/tailcalls.c +++ b/tools/testing/selftests/bpf/prog_tests/tailcalls.c @@ -219,10 +219,7 @@ static void test_tailcall_2(void) bpf_object__close(obj); } -/* test_tailcall_3 checks that the count value of the tail call limit - * enforcement matches with expectations. - */ -static void test_tailcall_3(void) +static void test_tailcall_count(const char *which) { int err, map_fd, prog_fd, main_fd, data_fd, i, val; struct bpf_map *prog_array, *data_map; @@ -231,7 +228,7 @@ static void test_tailcall_3(void) __u32 retval, duration; char buff[128] = {}; - err = bpf_prog_load("tailcall3.o", BPF_PROG_TYPE_SCHED_CLS, &obj, + err = bpf_prog_load(which, BPF_PROG_TYPE_SCHED_CLS, &obj, &prog_fd); if (CHECK_FAIL(err)) return; @@ -296,6 +293,22 @@ static void test_tailcall_3(void) bpf_object__close(obj); } +/* test_tailcall_3 checks that the count value of the tail call limit + * enforcement matches with expectations. JIT uses direct jump. + */ +static void test_tailcall_3(void) +{ + test_tailcall_count("tailcall3.o"); +} + +/* test_tailcall_6 checks that the count value of the tail call limit + * enforcement matches with expectations. JIT uses indirect jump. + */ +static void test_tailcall_6(void) +{ + test_tailcall_count("tailcall6.o"); +} + /* test_tailcall_4 checks that the kernel properly selects indirect jump * for the case where the key is not known. Latter is passed via global * data to select different targets we can compare return value of. @@ -822,6 +835,8 @@ void test_tailcalls(void) test_tailcall_4(); if (test__start_subtest("tailcall_5")) test_tailcall_5(); + if (test__start_subtest("tailcall_6")) + test_tailcall_6(); if (test__start_subtest("tailcall_bpf2bpf_1")) test_tailcall_bpf2bpf_1(); if (test__start_subtest("tailcall_bpf2bpf_2")) diff --git a/tools/testing/selftests/bpf/progs/tailcall6.c b/tools/testing/selftests/bpf/progs/tailcall6.c new file mode 100644 index 000000000000..9c298d908693 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/tailcall6.c @@ -0,0 +1,36 @@ +// SPDX-License-Identifier: GPL-2.0 +#include + +#include + +struct { + __uint(type, BPF_MAP_TYPE_PROG_ARRAY); + __uint(max_entries, 1); + __uint(key_size, sizeof(__u32)); + __uint(value_size, sizeof(__u32)); +} jmp_table SEC(".maps"); + +int count = 0; +volatile int which; + +SEC("classifier/0") +int bpf_func_0(struct __sk_buff *skb) +{ + count++; + if (__builtin_constant_p(which)) + __bpf_unreachable(); + bpf_tail_call(skb, &jmp_table, which); + return 1; +} + +SEC("classifier") +int entry(struct __sk_buff *skb) +{ + if (__builtin_constant_p(which)) + __bpf_unreachable(); + bpf_tail_call(skb, &jmp_table, which); + return 0; +} + +char __license[] SEC("license") = "GPL"; +int _version SEC("version") = 1; -- 2.27.0