This commit adds a test prog for vprintk which confirms that: * bpf_trace_vprintk is writing to dmesg * bpf_vprintk convenience macro works as expected * >3 args are printed
Approach and code are borrowed from trace_printk test.
Signed-off-by: Dave Marchevsky davemarchevsky@fb.com --- tools/testing/selftests/bpf/Makefile | 3 +- .../selftests/bpf/prog_tests/trace_vprintk.c | 75 +++++++++++++++++++ .../selftests/bpf/progs/trace_vprintk.c | 25 +++++++ 3 files changed, 102 insertions(+), 1 deletion(-) create mode 100644 tools/testing/selftests/bpf/prog_tests/trace_vprintk.c create mode 100644 tools/testing/selftests/bpf/progs/trace_vprintk.c
diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile index 2a58b7b5aea4..af5e7a1e9a7c 100644 --- a/tools/testing/selftests/bpf/Makefile +++ b/tools/testing/selftests/bpf/Makefile @@ -313,7 +313,8 @@ LINKED_SKELS := test_static_linked.skel.h linked_funcs.skel.h \ linked_vars.skel.h linked_maps.skel.h
LSKELS := kfunc_call_test.c fentry_test.c fexit_test.c fexit_sleep.c \ - test_ksyms_module.c test_ringbuf.c atomics.c trace_printk.c + test_ksyms_module.c test_ringbuf.c atomics.c trace_printk.c \ + trace_vprintk.c SKEL_BLACKLIST += $$(LSKELS)
test_static_linked.skel.h-deps := test_static_linked1.o test_static_linked2.o diff --git a/tools/testing/selftests/bpf/prog_tests/trace_vprintk.c b/tools/testing/selftests/bpf/prog_tests/trace_vprintk.c new file mode 100644 index 000000000000..fd70427d2918 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/trace_vprintk.c @@ -0,0 +1,75 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2021 Facebook */ + +#include <test_progs.h> + +#include "trace_vprintk.lskel.h" + +#define TRACEBUF "/sys/kernel/debug/tracing/trace_pipe" +#define SEARCHMSG "1,2,3,4,5,6,7,8,9,10" + +void test_trace_vprintk(void) +{ + int err, iter = 0, duration = 0, found = 0; + struct trace_vprintk__bss *bss; + struct trace_vprintk *skel; + char *buf = NULL; + FILE *fp = NULL; + size_t buflen; + + skel = trace_vprintk__open(); + if (CHECK(!skel, "skel_open", "failed to open skeleton\n")) + return; + + err = trace_vprintk__load(skel); + if (CHECK(err, "skel_load", "failed to load skeleton: %d\n", err)) + goto cleanup; + + bss = skel->bss; + + err = trace_vprintk__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_vprintk__detach(skel); + + if (CHECK(bss->trace_vprintk_ran == 0, + "bpf_trace_vprintk never ran", + "ran == %d", bss->trace_vprintk_ran)) + goto cleanup; + + if (CHECK(bss->trace_vprintk_ret <= 0, + "bpf_trace_vprintk returned <= 0 value", + "got %d", bss->trace_vprintk_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_vprintk_ran) + break; + if (++iter > 1000) + break; + } + + if (CHECK(!found, "message from bpf_trace_vprintk not found", + "no instance of %s in %s", SEARCHMSG, TRACEBUF)) + goto cleanup; + +cleanup: + trace_vprintk__destroy(skel); + free(buf); + if (fp) + fclose(fp); +} diff --git a/tools/testing/selftests/bpf/progs/trace_vprintk.c b/tools/testing/selftests/bpf/progs/trace_vprintk.c new file mode 100644 index 000000000000..993439a19e1e --- /dev/null +++ b/tools/testing/selftests/bpf/progs/trace_vprintk.c @@ -0,0 +1,25 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2021 Facebook */ + +#include "vmlinux.h" +#include <bpf/bpf_helpers.h> +#include <bpf/bpf_tracing.h> + +char _license[] SEC("license") = "GPL"; + +int trace_vprintk_ret = 0; +int trace_vprintk_ran = 0; + +SEC("fentry/__x64_sys_nanosleep") +int sys_enter(void *ctx) +{ + static const char one[] = "1"; + static const char three[] = "3"; + static const char five[] = "5"; + static const char seven[] = "7"; + static const char nine[] = "9"; + + trace_vprintk_ret = bpf_vprintk("%s,%d,%s,%d,%s,%d,%s,%d,%s,%d %d\n", + one, 2, three, 4, five, 6, seven, 8, nine, 10, ++trace_vprintk_ran); + return 0; +}