kernel/tools/testing/selftests/bpf/progs/test_vmlinux.c, branch linux-6.2.y

selftests/bpf: Fix test_vmlinux test to use bpf_probe_read_user()

2020-08-19T00:16:15Z

The test is reading UAPI kernel structure from user-space. So it doesn't need CO-RE relocations and has to use bpf_probe_read_user(). Fixes: acbd06206bbb ("selftests/bpf: Add vmlinux.h selftest exercising tracing of syscalls") Signed-off-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20200818213356.2629020-6-andriin@fb.com

selftests/bpf: Switch test_vmlinux to use hrtimer_range_start_ns.

2020-07-01T22:10:27Z

The test_vmlinux test uses hrtimer_nanosleep as hook to test tracing programs. But in a kernel built by clang, which performs more aggresive inlining, that function gets inlined into its caller SyS_nanosleep. Therefore, even though fentry and kprobe do hook on the function, they aren't triggered by the call to nanosleep in the test. A possible fix is switching to use a function that is less likely to be inlined, such as hrtimer_range_start_ns. The EXPORT_SYMBOL functions shouldn't be inlined based on the description of [1], therefore safe to use for this test. Also the arguments of this function include the duration of sleep, therefore suitable for test verification. [1] af3b56289be1 time: don't inline EXPORT_SYMBOL functions Tested: In a clang build kernel, before this change, the test fails: test_vmlinux:PASS:skel_open 0 nsec test_vmlinux:PASS:skel_attach 0 nsec test_vmlinux:PASS:tp 0 nsec test_vmlinux:PASS:raw_tp 0 nsec test_vmlinux:PASS:tp_btf 0 nsec test_vmlinux:FAIL:kprobe not called test_vmlinux:FAIL:fentry not called After switching to hrtimer_range_start_ns, the test passes: test_vmlinux:PASS:skel_open 0 nsec test_vmlinux:PASS:skel_attach 0 nsec test_vmlinux:PASS:tp 0 nsec test_vmlinux:PASS:raw_tp 0 nsec test_vmlinux:PASS:tp_btf 0 nsec test_vmlinux:PASS:kprobe 0 nsec test_vmlinux:PASS:fentry 0 nsec Signed-off-by: Hao Luo Signed-off-by: Alexei Starovoitov Acked-by: Andrii Nakryiko Acked-by: Yonghong Song Link: https://lore.kernel.org/bpf/20200701175315.1161242-1-haoluo@google.com

selftests/bpf: Add vmlinux.h selftest exercising tracing of syscalls

2020-03-13T22:30:53Z

Add vmlinux.h generation to selftest/bpf's Makefile. Use it from newly added test_vmlinux to trace nanosleep syscall using 5 different types of programs: - tracepoint; - raw tracepoint; - raw tracepoint w/ direct memory reads (tp_btf); - kprobe; - fentry. These programs are realistic variants of real-life tracing programs, excercising vmlinux.h's usage with tracing applications. Signed-off-by: Andrii Nakryiko Signed-off-by: Daniel Borkmann Acked-by: Martin KaFai Lau Link: https://lore.kernel.org/bpf/20200313172336.1879637-5-andriin@fb.com