bpf: Add bpf_jit_supports_fsession()

The added fsession does not prevent running on those architectures, that
haven't added fsession support.

For example, try to run fsession tests on arm64:

test_fsession_basic:PASS:fsession_test__open_and_load 0 nsec
test_fsession_basic:PASS:fsession_attach 0 nsec
check_result:FAIL:test_run_opts err unexpected error: -14 (errno 14)

In order to prevent such errors, add bpf_jit_supports_fsession() to guard
those architectures.

Fixes: 2d419c44658f ("bpf: add fsession support")
Acked-by: Puranjay Mohan <puranjay@kernel.org>
Tested-by: Puranjay Mohan <puranjay@kernel.org>
Signed-off-by: Leon Hwang <leon.hwang@linux.dev>
Link: https://lore.kernel.org/r/20260131144950.16294-2-leon.hwang@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c
index 5a075e06cf45afa0235ca5ad2e99a0602e31a380..070ba80e39d70f75d59556469d54f3786bb146ad 100644 (file)
--- a/arch/x86/net/bpf_jit_comp.c
+++ b/arch/x86/net/bpf_jit_comp.c
@@ -4112,3 +4112,8 @@ bool bpf_jit_supports_timed_may_goto(void)
 {
        return true;
 }
+
+bool bpf_jit_supports_fsession(void)
+{
+       return true;
+}

diff --git a/include/linux/filter.h b/include/linux/filter.h
index fd54fed8f95f3b0e6ddeb436bc96b861c6d98972..4e1cb4f91f49f00b142a5ac93750a65f5cb07f3e 100644 (file)
--- a/include/linux/filter.h
+++ b/include/linux/filter.h
@@ -1167,6 +1167,7 @@ bool bpf_jit_supports_arena(void);
 bool bpf_jit_supports_insn(struct bpf_insn *insn, bool in_arena);
 bool bpf_jit_supports_private_stack(void);
 bool bpf_jit_supports_timed_may_goto(void);
+bool bpf_jit_supports_fsession(void);
 u64 bpf_arch_uaddress_limit(void);
 void arch_bpf_stack_walk(bool (*consume_fn)(void *cookie, u64 ip, u64 sp, u64 bp), void *cookie);
 u64 arch_bpf_timed_may_goto(void);

diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index 5ebece600aebaa9d24bafc951cac50c464208ecf..dc906dfdff941479c7956acdada37a857e09b585 100644 (file)
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -3144,6 +3144,11 @@ bool __weak bpf_jit_supports_insn(struct bpf_insn *insn, bool in_arena)
        return false;
 }
 
+bool __weak bpf_jit_supports_fsession(void)
+{
+       return false;
+}
+
 u64 __weak bpf_arch_uaddress_limit(void)
 {
 #if defined(CONFIG_64BIT) && defined(CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE)

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 256cc5c1a7dff0bdedfd76118b4651ab3a142f10..6b62b6d57175ad9d3abfba9f7f4321d51b02bc34 100644 (file)
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -24828,6 +24828,11 @@ int bpf_check_attach_target(struct bpf_verifier_log *log,
        case BPF_TRACE_FENTRY:
        case BPF_TRACE_FEXIT:
        case BPF_TRACE_FSESSION:
+               if (prog->expected_attach_type == BPF_TRACE_FSESSION &&
+                   !bpf_jit_supports_fsession()) {
+                       bpf_log(log, "JIT does not support fsession\n");
+                       return -EOPNOTSUPP;
+               }
                if (!btf_type_is_func(t)) {
                        bpf_log(log, "attach_btf_id %u is not a function\n",
                                btf_id);

diff --git a/tools/testing/selftests/bpf/prog_tests/fsession_test.c b/tools/testing/selftests/bpf/prog_tests/fsession_test.c
index 0c4b428e1cee98cd6e4174fba54c88ec59bd488f..a299aeb8cc2e475da415564b955c29219748c89d 100644 (file)
--- a/tools/testing/selftests/bpf/prog_tests/fsession_test.c
+++ b/tools/testing/selftests/bpf/prog_tests/fsession_test.c
@@ -29,8 +29,16 @@ static void test_fsession_basic(void)
        struct fsession_test *skel = NULL;
        int err;
 
-       skel = fsession_test__open_and_load();
-       if (!ASSERT_OK_PTR(skel, "fsession_test__open_and_load"))
+       skel = fsession_test__open();
+       if (!ASSERT_OK_PTR(skel, "fsession_test__open"))
+               return;
+
+       err = fsession_test__load(skel);
+       if (err == -EOPNOTSUPP) {
+               test__skip();
+               goto cleanup;
+       }
+       if (!ASSERT_OK(err, "fsession_test__load"))
                goto cleanup;
 
        err = fsession_test__attach(skel);
@@ -47,8 +55,16 @@ static void test_fsession_reattach(void)
        struct fsession_test *skel = NULL;
        int err;
 
-       skel = fsession_test__open_and_load();
-       if (!ASSERT_OK_PTR(skel, "fsession_test__open_and_load"))
+       skel = fsession_test__open();
+       if (!ASSERT_OK_PTR(skel, "fsession_test__open"))
+               return;
+
+       err = fsession_test__load(skel);
+       if (err == -EOPNOTSUPP) {
+               test__skip();
+               goto cleanup;
+       }
+       if (!ASSERT_OK(err, "fsession_test__load"))
                goto cleanup;
 
        /* first attach */
@@ -94,6 +110,10 @@ static void test_fsession_cookie(void)
        bpf_program__set_autoload(skel->progs.test6, false);
 
        err = fsession_test__load(skel);
+       if (err == -EOPNOTSUPP) {
+               test__skip();
+               goto cleanup;
+       }
        if (!ASSERT_OK(err, "fsession_test__load"))
                goto cleanup;
 
@@ -111,10 +131,6 @@ cleanup:
 
 void test_fsession_test(void)
 {
-#if !defined(__x86_64__)
-       test__skip();
-       return;
-#endif
        if (test__start_subtest("fsession_test"))
                test_fsession_basic();
        if (test__start_subtest("fsession_reattach"))