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authorYonghong Song <yhs@fb.com>2017-11-30 13:47:55 -0800
committerDaniel Borkmann <daniel@iogearbox.net>2017-12-01 02:59:21 +0100
commit0ec9552b43b98deb882bf48efd347be4bd7afc9f (patch)
treea71ca8775603c52eb8c8d086f02505a3459f34b6 /samples/bpf
parentc8c088ba0edf65044c254b96fc438c91914aaab0 (diff)
downloadlinux-0ec9552b43b98deb882bf48efd347be4bd7afc9f.tar.bz2
samples/bpf: add error checking for perf ioctl calls in bpf loader
load_bpf_file() should fail if ioctl with command PERF_EVENT_IOC_ENABLE and PERF_EVENT_IOC_SET_BPF fails. When they do fail, proper error messages are printed. With this change, the below "syscall_tp" run shows that the maximum number of bpf progs attaching to the same perf tracepoint is indeed enforced. $ ./syscall_tp -i 64 prog #0: map ids 4 5 ... prog #63: map ids 382 383 $ ./syscall_tp -i 65 prog #0: map ids 4 5 ... prog #64: map ids 388 389 ioctl PERF_EVENT_IOC_SET_BPF failed err Argument list too long Signed-off-by: Yonghong Song <yhs@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Diffstat (limited to 'samples/bpf')
-rw-r--r--samples/bpf/bpf_load.c14
1 files changed, 12 insertions, 2 deletions
diff --git a/samples/bpf/bpf_load.c b/samples/bpf/bpf_load.c
index 522ca9252d6c..242631aa4ea2 100644
--- a/samples/bpf/bpf_load.c
+++ b/samples/bpf/bpf_load.c
@@ -193,8 +193,18 @@ static int load_and_attach(const char *event, struct bpf_insn *prog, int size)
return -1;
}
event_fd[prog_cnt - 1] = efd;
- ioctl(efd, PERF_EVENT_IOC_ENABLE, 0);
- ioctl(efd, PERF_EVENT_IOC_SET_BPF, fd);
+ err = ioctl(efd, PERF_EVENT_IOC_ENABLE, 0);
+ if (err < 0) {
+ printf("ioctl PERF_EVENT_IOC_ENABLE failed err %s\n",
+ strerror(errno));
+ return -1;
+ }
+ err = ioctl(efd, PERF_EVENT_IOC_SET_BPF, fd);
+ if (err < 0) {
+ printf("ioctl PERF_EVENT_IOC_SET_BPF failed err %s\n",
+ strerror(errno));
+ return -1;
+ }
return 0;
}