From: Alan Maguire <alan.maguire@oracle.com>
To: rostedt@goodmis.org, mingo@redhat.com, ast@kernel.org,
daniel@iogearbox.net
Cc: kafai@fb.com, songliubraving@fb.com, yhs@fb.com, andriin@fb.com,
john.fastabend@gmail.com, kpsingh@chromium.org,
linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
bpf@vger.kernel.org, Alan Maguire <alan.maguire@oracle.com>
Subject: [PATCH v3 bpf-next 2/2] selftests/bpf: add selftests verifying bpf_trace_printk() behaviour
Date: Mon, 13 Jul 2020 12:52:34 +0100 [thread overview]
Message-ID: <1594641154-18897-3-git-send-email-alan.maguire@oracle.com> (raw)
In-Reply-To: <1594641154-18897-1-git-send-email-alan.maguire@oracle.com>
Simple selftests that verifies bpf_trace_printk() returns a sensible
value and tracing messages appear.
Signed-off-by: Alan Maguire <alan.maguire@oracle.com>
Acked-by: Andrii Nakryiko <andriin@fb.com>
---
.../selftests/bpf/prog_tests/trace_printk.c | 75 ++++++++++++++++++++++
tools/testing/selftests/bpf/progs/trace_printk.c | 21 ++++++
2 files changed, 96 insertions(+)
create mode 100644 tools/testing/selftests/bpf/prog_tests/trace_printk.c
create mode 100644 tools/testing/selftests/bpf/progs/trace_printk.c
diff --git a/tools/testing/selftests/bpf/prog_tests/trace_printk.c b/tools/testing/selftests/bpf/prog_tests/trace_printk.c
new file mode 100644
index 0000000..39b0dec
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/trace_printk.c
@@ -0,0 +1,75 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2020, Oracle and/or its affiliates. */
+
+#include <test_progs.h>
+
+#include "trace_printk.skel.h"
+
+#define TRACEBUF "/sys/kernel/debug/tracing/trace_pipe"
+#define SEARCHMSG "testing,testing"
+
+void test_trace_printk(void)
+{
+ int err, iter = 0, duration = 0, found = 0;
+ struct trace_printk__bss *bss;
+ struct trace_printk *skel;
+ char *buf = NULL;
+ FILE *fp = NULL;
+ size_t buflen;
+
+ skel = trace_printk__open();
+ if (CHECK(!skel, "skel_open", "failed to open skeleton\n"))
+ return;
+
+ err = trace_printk__load(skel);
+ if (CHECK(err, "skel_load", "failed to load skeleton: %d\n", err))
+ goto cleanup;
+
+ bss = skel->bss;
+
+ err = trace_printk__attach(skel);
+ if (CHECK(err, "skel_attach", "skeleton attach failed: %d\n", err))
+ goto cleanup;
+
+ fp = fopen(TRACEBUF, "r");
+ if (CHECK(fp == NULL, "could not open trace buffer",
+ "error %d opening %s", errno, TRACEBUF))
+ goto cleanup;
+
+ /* We do not want to wait forever if this test fails... */
+ fcntl(fileno(fp), F_SETFL, O_NONBLOCK);
+
+ /* wait for tracepoint to trigger */
+ usleep(1);
+ trace_printk__detach(skel);
+
+ if (CHECK(bss->trace_printk_ran == 0,
+ "bpf_trace_printk never ran",
+ "ran == %d", bss->trace_printk_ran))
+ goto cleanup;
+
+ if (CHECK(bss->trace_printk_ret <= 0,
+ "bpf_trace_printk returned <= 0 value",
+ "got %d", bss->trace_printk_ret))
+ goto cleanup;
+
+ /* verify our search string is in the trace buffer */
+ while (getline(&buf, &buflen, fp) >= 0 || errno == EAGAIN) {
+ if (strstr(buf, SEARCHMSG) != NULL)
+ found++;
+ if (found == bss->trace_printk_ran)
+ break;
+ if (++iter > 1000)
+ break;
+ }
+
+ if (CHECK(!found, "message from bpf_trace_printk not found",
+ "no instance of %s in %s", SEARCHMSG, TRACEBUF))
+ goto cleanup;
+
+cleanup:
+ trace_printk__destroy(skel);
+ free(buf);
+ if (fp)
+ fclose(fp);
+}
diff --git a/tools/testing/selftests/bpf/progs/trace_printk.c b/tools/testing/selftests/bpf/progs/trace_printk.c
new file mode 100644
index 0000000..8ca7f39
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/trace_printk.c
@@ -0,0 +1,21 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2020, Oracle and/or its affiliates.
+
+#include "vmlinux.h"
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+
+char _license[] SEC("license") = "GPL";
+
+int trace_printk_ret = 0;
+int trace_printk_ran = 0;
+
+SEC("tp/raw_syscalls/sys_enter")
+int sys_enter(void *ctx)
+{
+ static const char fmt[] = "testing,testing %d\n";
+
+ trace_printk_ret = bpf_trace_printk(fmt, sizeof(fmt),
+ ++trace_printk_ran);
+ return 0;
+}
--
1.8.3.1
next prev parent reply other threads:[~2020-07-13 11:53 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-13 11:52 [PATCH v3 bpf-next 0/2] bpf: fix use of trace_printk() in BPF Alan Maguire
2020-07-13 11:52 ` [PATCH v3 bpf-next 1/2] bpf: use dedicated bpf_trace_printk event instead of trace_printk() Alan Maguire
2020-07-13 11:52 ` Alan Maguire [this message]
2020-07-14 0:01 ` [PATCH v3 bpf-next 0/2] bpf: fix use of trace_printk() in BPF Alexei Starovoitov
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1594641154-18897-3-git-send-email-alan.maguire@oracle.com \
--to=alan.maguire@oracle.com \
--cc=andriin@fb.com \
--cc=ast@kernel.org \
--cc=bpf@vger.kernel.org \
--cc=daniel@iogearbox.net \
--cc=john.fastabend@gmail.com \
--cc=kafai@fb.com \
--cc=kpsingh@chromium.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@redhat.com \
--cc=netdev@vger.kernel.org \
--cc=rostedt@goodmis.org \
--cc=songliubraving@fb.com \
--cc=yhs@fb.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).