perf test bpf: Hook on epoll_pwait()

The 'perf test bpf' was hooking a eBPF program on the SyS_epoll_wait()
kernel function, that was what the epoll_wait() glibc function ended up
calling, but since at least glibc 2.26, the one that comes with, for
instance, Fedora 27, glibc ends up calling SyS_epoll_pwait() when
epoll_wait() is used, causing this 'perf test' entry to fail.

So switch to using epoll_pwait() and hook the eBPF program to the
SyS_epoll_pwait() kernel function to make it work on a wider range of
glibc and kernel versions.

Tested-by: Wang Nan <wangnan0@huawei.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-zynvquy63er8s5mrgsz65pto@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/tests/bpf-script-example.c b/tools/perf/tests/bpf-script-example.c
index 268e5f8e4aa277c28d04209ca907728e1811ea5b..e4123c1b0e8839054188c08d2df3c45052c85b49 100644 (file)
--- a/tools/perf/tests/bpf-script-example.c
+++ b/tools/perf/tests/bpf-script-example.c
@@ -31,8 +31,8 @@ struct bpf_map_def SEC("maps") flip_table = {
        .max_entries = 1,
 };
 
-SEC("func=SyS_epoll_wait")
-int bpf_func__SyS_epoll_wait(void *ctx)
+SEC("func=SyS_epoll_pwait")
+int bpf_func__SyS_epoll_pwait(void *ctx)
 {
        int ind =0;
        int *flag = bpf_map_lookup_elem(&flip_table, &ind);

diff --git a/tools/perf/tests/bpf.c b/tools/perf/tests/bpf.c
index 0512f1b5bfdba8e18dfbb05cab8c2cf862593499..8e709c9d512c48fd49cf2825473f64ad5d2db4ef 100644 (file)
--- a/tools/perf/tests/bpf.c
+++ b/tools/perf/tests/bpf.c
@@ -19,13 +19,13 @@
 
 #ifdef HAVE_LIBBPF_SUPPORT
 
-static int epoll_wait_loop(void)
+static int epoll_pwait_loop(void)
 {
        int i;
 
        /* Should fail NR_ITERS times */
        for (i = 0; i < NR_ITERS; i++)
-               epoll_wait(-(i + 1), NULL, 0, 0);
+               epoll_pwait(-(i + 1), NULL, 0, 0, NULL);
        return 0;
 }
 
@@ -68,7 +68,7 @@ static struct {
                .name             = "[basic_bpf_test]",
                .msg_compile_fail = "fix 'perf test LLVM' first",
                .msg_load_fail    = "load bpf object failed",
-               .target_func      = &epoll_wait_loop,
+               .target_func      = &epoll_pwait_loop,
                .expect_result    = (NR_ITERS + 1) / 2,
        },
        {
@@ -77,7 +77,7 @@ static struct {
                .name             = "[bpf_pinning]",
                .msg_compile_fail = "fix kbuild first",
                .msg_load_fail    = "check your vmlinux setting?",
-               .target_func      = &epoll_wait_loop,
+               .target_func      = &epoll_pwait_loop,
                .expect_result    = (NR_ITERS + 1) / 2,
                .pin              = true,
        },