kernel/tools/testing/selftests/bpf/urandom_read.c, branch linux-5.2.y

selftests: bpf: modify urandom_read and link it non-statically

2019-03-22T02:37:30Z

After some experiences I found that urandom_read does not need to be linked statically. When the 'read' syscall call is moved to separate non-inlined function then bpf_get_stackid() is able to find the executable in stack trace and extract its build_id from it. Signed-off-by: Ivan Vecera Signed-off-by: Alexei Starovoitov

bpf: add selftest for stackmap with build_id in NMI context

2018-05-14T21:29:45Z

This new test captures stackmap with build_id with hardware event PERF_COUNT_HW_CPU_CYCLES. Because we only support one ips-to-build_id lookup per cpu in NMI context, stack_amap will not be able to do the lookup in this test. Therefore, we didn't do compare_stack_ips(), as it will alwasy fail. urandom_read.c is extended to run configurable cycles so that it can be caught by the perf event. Signed-off-by: Song Liu Signed-off-by: Daniel Borkmann

bpf: add selftest for stackmap with BPF_F_STACK_BUILD_ID

2018-03-15T00:10:02Z

test_stacktrace_build_id() is added. It accesses tracepoint urandom_read with "dd" and "urandom_read" and gathers stack traces. Then it reads the stack traces from the stackmap. urandom_read is a statically link binary that reads from /dev/urandom. test_stacktrace_build_id() calls readelf to read build ID of urandom_read and compares it with build ID from the stackmap. Signed-off-by: Song Liu Signed-off-by: Daniel Borkmann