When attaching ebpf programs to functions through fentry/fexit, the generated trampolines can not really make sure about the arguments exact location on the stack if those are structures: those structures can be altered with attributes such as packed or aligned(x), but this information is not encoded in BTF.
Update tracing_struct_many_args test to check that programs can not be attached on those specific functions. Not all architectures can use the same number of registers to pass arguments, so define a testing function that makes all currently supported architectures start passing arguments on stack (-> more than 8 args)
Signed-off-by: Alexis Lothoré (eBPF Foundation) alexis.lothore@bootlin.com --- .../selftests/bpf/prog_tests/tracing_struct.c | 37 +----------- .../selftests/bpf/progs/tracing_struct_many_args.c | 70 ---------------------- .../testing/selftests/bpf/test_kmods/bpf_testmod.c | 43 ++----------- 3 files changed, 6 insertions(+), 144 deletions(-)
diff --git a/tools/testing/selftests/bpf/prog_tests/tracing_struct.c b/tools/testing/selftests/bpf/prog_tests/tracing_struct.c index 19e68d4b353278bf8e2917e62f62c89d14d7fe80..a084f6e5eca4e97b463950feba2142a628e9ec72 100644 --- a/tools/testing/selftests/bpf/prog_tests/tracing_struct.c +++ b/tools/testing/selftests/bpf/prog_tests/tracing_struct.c @@ -70,44 +70,9 @@ static void test_struct_many_args(void) return;
err = tracing_struct_many_args__attach(skel); - if (!ASSERT_OK(err, "tracing_struct_many_args__attach")) + if (!ASSERT_EQ(err, -ENOTSUPP, "tracing_struct_many_args__attach")) goto destroy_skel;
- ASSERT_OK(trigger_module_test_read(256), "trigger_read"); - - ASSERT_EQ(skel->bss->t7_a, 16, "t7:a"); - ASSERT_EQ(skel->bss->t7_b, 17, "t7:b"); - ASSERT_EQ(skel->bss->t7_c, 18, "t7:c"); - ASSERT_EQ(skel->bss->t7_d, 19, "t7:d"); - ASSERT_EQ(skel->bss->t7_e, 20, "t7:e"); - ASSERT_EQ(skel->bss->t7_f_a, 21, "t7:f.a"); - ASSERT_EQ(skel->bss->t7_f_b, 22, "t7:f.b"); - ASSERT_EQ(skel->bss->t7_ret, 133, "t7 ret"); - - ASSERT_EQ(skel->bss->t8_a, 16, "t8:a"); - ASSERT_EQ(skel->bss->t8_b, 17, "t8:b"); - ASSERT_EQ(skel->bss->t8_c, 18, "t8:c"); - ASSERT_EQ(skel->bss->t8_d, 19, "t8:d"); - ASSERT_EQ(skel->bss->t8_e, 20, "t8:e"); - ASSERT_EQ(skel->bss->t8_f_a, 21, "t8:f.a"); - ASSERT_EQ(skel->bss->t8_f_b, 22, "t8:f.b"); - ASSERT_EQ(skel->bss->t8_g, 23, "t8:g"); - ASSERT_EQ(skel->bss->t8_ret, 156, "t8 ret"); - - ASSERT_EQ(skel->bss->t9_a, 16, "t9:a"); - ASSERT_EQ(skel->bss->t9_b, 17, "t9:b"); - ASSERT_EQ(skel->bss->t9_c, 18, "t9:c"); - ASSERT_EQ(skel->bss->t9_d, 19, "t9:d"); - ASSERT_EQ(skel->bss->t9_e, 20, "t9:e"); - ASSERT_EQ(skel->bss->t9_f, 21, "t9:f"); - ASSERT_EQ(skel->bss->t9_g, 22, "t9:f"); - ASSERT_EQ(skel->bss->t9_h_a, 23, "t9:h.a"); - ASSERT_EQ(skel->bss->t9_h_b, 24, "t9:h.b"); - ASSERT_EQ(skel->bss->t9_h_c, 25, "t9:h.c"); - ASSERT_EQ(skel->bss->t9_h_d, 26, "t9:h.d"); - ASSERT_EQ(skel->bss->t9_i, 27, "t9:i"); - ASSERT_EQ(skel->bss->t9_ret, 258, "t9 ret"); - destroy_skel: tracing_struct_many_args__destroy(skel); } diff --git a/tools/testing/selftests/bpf/progs/tracing_struct_many_args.c b/tools/testing/selftests/bpf/progs/tracing_struct_many_args.c index 4742012ace06af949d7f15a21131aaef7ab006e4..1cbedcdc1c42e1fe2f118fdbd1a4ab7fe48b52fb 100644 --- a/tools/testing/selftests/bpf/progs/tracing_struct_many_args.c +++ b/tools/testing/selftests/bpf/progs/tracing_struct_many_args.c @@ -8,28 +8,11 @@ struct bpf_testmod_struct_arg_4 { int b; };
-struct bpf_testmod_struct_arg_5 { - char a; - short b; - int c; - long d; -}; - -long t7_a, t7_b, t7_c, t7_d, t7_e, t7_f_a, t7_f_b, t7_ret; -long t8_a, t8_b, t8_c, t8_d, t8_e, t8_f_a, t8_f_b, t8_g, t8_ret; -long t9_a, t9_b, t9_c, t9_d, t9_e, t9_f, t9_g, t9_h_a, t9_h_b, t9_h_c, t9_h_d, t9_i, t9_ret;
SEC("fentry/bpf_testmod_test_struct_arg_7") int BPF_PROG2(test_struct_many_args_1, __u64, a, void *, b, short, c, int, d, void *, e, struct bpf_testmod_struct_arg_4, f) { - t7_a = a; - t7_b = (long)b; - t7_c = c; - t7_d = d; - t7_e = (long)e; - t7_f_a = f.a; - t7_f_b = f.b; return 0; }
@@ -37,59 +20,6 @@ SEC("fexit/bpf_testmod_test_struct_arg_7") int BPF_PROG2(test_struct_many_args_2, __u64, a, void *, b, short, c, int, d, void *, e, struct bpf_testmod_struct_arg_4, f, int, ret) { - t7_ret = ret; - return 0; -} - -SEC("fentry/bpf_testmod_test_struct_arg_8") -int BPF_PROG2(test_struct_many_args_3, __u64, a, void *, b, short, c, int, d, - void *, e, struct bpf_testmod_struct_arg_4, f, int, g) -{ - t8_a = a; - t8_b = (long)b; - t8_c = c; - t8_d = d; - t8_e = (long)e; - t8_f_a = f.a; - t8_f_b = f.b; - t8_g = g; - return 0; -} - -SEC("fexit/bpf_testmod_test_struct_arg_8") -int BPF_PROG2(test_struct_many_args_4, __u64, a, void *, b, short, c, int, d, - void *, e, struct bpf_testmod_struct_arg_4, f, int, g, - int, ret) -{ - t8_ret = ret; return 0; } - -SEC("fentry/bpf_testmod_test_struct_arg_9") -int BPF_PROG2(test_struct_many_args_5, __u64, a, void *, b, short, c, int, d, void *, e, - char, f, short, g, struct bpf_testmod_struct_arg_5, h, long, i) -{ - t9_a = a; - t9_b = (long)b; - t9_c = c; - t9_d = d; - t9_e = (long)e; - t9_f = f; - t9_g = g; - t9_h_a = h.a; - t9_h_b = h.b; - t9_h_c = h.c; - t9_h_d = h.d; - t9_i = i; - return 0; -} - -SEC("fexit/bpf_testmod_test_struct_arg_9") -int BPF_PROG2(test_struct_many_args_6, __u64, a, void *, b, short, c, int, d, void *, e, - char, f, short, g, struct bpf_testmod_struct_arg_5, h, long, i, int, ret) -{ - t9_ret = ret; - return 0; -} - char _license[] SEC("license") = "GPL"; diff --git a/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c b/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c index e9e918cdf31ff2b15bf41302ad429e8683b834d6..ff6a4a0fb73679c6c4831ae0662bce2080e53c23 100644 --- a/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c +++ b/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c @@ -55,13 +55,6 @@ struct bpf_testmod_struct_arg_4 { int b; };
-struct bpf_testmod_struct_arg_5 { - char a; - short b; - int c; - long d; -}; - __bpf_hook_start();
noinline int @@ -101,30 +94,10 @@ bpf_testmod_test_struct_arg_6(struct bpf_testmod_struct_arg_3 *a) { return bpf_testmod_test_struct_arg_result; }
-noinline int -bpf_testmod_test_struct_arg_7(u64 a, void *b, short c, int d, void *e, - struct bpf_testmod_struct_arg_4 f) -{ - bpf_testmod_test_struct_arg_result = a + (long)b + c + d + - (long)e + f.a + f.b; - return bpf_testmod_test_struct_arg_result; -} - -noinline int -bpf_testmod_test_struct_arg_8(u64 a, void *b, short c, int d, void *e, - struct bpf_testmod_struct_arg_4 f, int g) +noinline int bpf_testmod_test_struct_arg_7(u64 a, void *b, short c, int d, + void *e, u64 f, u64 g, u64 h, + struct bpf_testmod_struct_arg_4 i) { - bpf_testmod_test_struct_arg_result = a + (long)b + c + d + - (long)e + f.a + f.b + g; - return bpf_testmod_test_struct_arg_result; -} - -noinline int -bpf_testmod_test_struct_arg_9(u64 a, void *b, short c, int d, void *e, char f, - short g, struct bpf_testmod_struct_arg_5 h, long i) -{ - bpf_testmod_test_struct_arg_result = a + (long)b + c + d + (long)e + - f + g + h.a + h.b + h.c + h.d + i; return bpf_testmod_test_struct_arg_result; }
@@ -397,7 +370,6 @@ bpf_testmod_test_read(struct file *file, struct kobject *kobj, struct bpf_testmod_struct_arg_2 struct_arg2 = {2, 3}; struct bpf_testmod_struct_arg_3 *struct_arg3; struct bpf_testmod_struct_arg_4 struct_arg4 = {21, 22}; - struct bpf_testmod_struct_arg_5 struct_arg5 = {23, 24, 25, 26}; int i = 1;
while (bpf_testmod_return_ptr(i)) @@ -408,13 +380,8 @@ bpf_testmod_test_read(struct file *file, struct kobject *kobj, (void)bpf_testmod_test_struct_arg_3(1, 4, struct_arg2); (void)bpf_testmod_test_struct_arg_4(struct_arg1, 1, 2, 3, struct_arg2); (void)bpf_testmod_test_struct_arg_5(); - (void)bpf_testmod_test_struct_arg_7(16, (void *)17, 18, 19, - (void *)20, struct_arg4); - (void)bpf_testmod_test_struct_arg_8(16, (void *)17, 18, 19, - (void *)20, struct_arg4, 23); - (void)bpf_testmod_test_struct_arg_9(16, (void *)17, 18, 19, (void *)20, - 21, 22, struct_arg5, 27); - + (void)bpf_testmod_test_struct_arg_7(16, (void *)17, 18, 19, (void *)20, + 21, 22, 23, struct_arg4); (void)bpf_testmod_test_arg_ptr_to_struct(&struct_arg1_2);
(void)trace_bpf_testmod_test_raw_tp_null_tp(NULL);