diff options
| -rw-r--r-- | kernel/trace/Makefile | 2 | ||||
| -rw-r--r-- | kernel/trace/bpf_trace.c | 42 | ||||
| -rw-r--r-- | kernel/trace/bpf_trace.h | 34 | ||||
| -rw-r--r-- | tools/testing/selftests/bpf/prog_tests/trace_printk.c | 75 | ||||
| -rw-r--r-- | tools/testing/selftests/bpf/progs/trace_printk.c | 21 |
5 files changed, 169 insertions, 5 deletions
diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile index 6575bb0a0434..aeba5ee7325a 100644 --- a/kernel/trace/Makefile +++ b/kernel/trace/Makefile @@ -31,6 +31,8 @@ ifdef CONFIG_GCOV_PROFILE_FTRACE GCOV_PROFILE := y endif +CFLAGS_bpf_trace.o := -I$(src) + CFLAGS_trace_benchmark.o := -I$(src) CFLAGS_trace_events_filter.o := -I$(src) diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index e178e8e32b33..3cc0dcb60ca2 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -11,6 +11,7 @@ #include <linux/uaccess.h> #include <linux/ctype.h> #include <linux/kprobes.h> +#include <linux/spinlock.h> #include <linux/syscalls.h> #include <linux/error-injection.h> #include <linux/btf_ids.h> @@ -20,6 +21,9 @@ #include "trace_probe.h" #include "trace.h" +#define CREATE_TRACE_POINTS +#include "bpf_trace.h" + #define bpf_event_rcu_dereference(p) \ rcu_dereference_protected(p, lockdep_is_held(&bpf_event_mutex)) @@ -375,6 +379,30 @@ static void bpf_trace_copy_string(char *buf, void *unsafe_ptr, char fmt_ptype, } } +static DEFINE_RAW_SPINLOCK(trace_printk_lock); + +#define BPF_TRACE_PRINTK_SIZE 1024 + +static inline __printf(1, 0) int bpf_do_trace_printk(const char *fmt, ...) +{ + static char buf[BPF_TRACE_PRINTK_SIZE]; + unsigned long flags; + va_list ap; + int ret; + + raw_spin_lock_irqsave(&trace_printk_lock, flags); + va_start(ap, fmt); + ret = vsnprintf(buf, sizeof(buf), fmt, ap); + va_end(ap); + /* vsnprintf() will not append null for zero-length strings */ + if (ret == 0) + buf[0] = '\0'; + trace_bpf_trace_printk(buf); + raw_spin_unlock_irqrestore(&trace_printk_lock, flags); + + return ret; +} + /* * Only limited trace_printk() conversion specifiers allowed: * %d %i %u %x %ld %li %lu %lx %lld %lli %llu %llx %p %pB %pks %pus %s @@ -484,8 +512,7 @@ fmt_next: */ #define __BPF_TP_EMIT() __BPF_ARG3_TP() #define __BPF_TP(...) \ - __trace_printk(0 /* Fake ip */, \ - fmt, ##__VA_ARGS__) + bpf_do_trace_printk(fmt, ##__VA_ARGS__) #define __BPF_ARG1_TP(...) \ ((mod[0] == 2 || (mod[0] == 1 && __BITS_PER_LONG == 64)) \ @@ -522,10 +549,15 @@ static const struct bpf_func_proto bpf_trace_printk_proto = { const struct bpf_func_proto *bpf_get_trace_printk_proto(void) { /* - * this program might be calling bpf_trace_printk, - * so allocate per-cpu printk buffers + * This program might be calling bpf_trace_printk, + * so enable the associated bpf_trace/bpf_trace_printk event. + * Repeat this each time as it is possible a user has + * disabled bpf_trace_printk events. By loading a program + * calling bpf_trace_printk() however the user has expressed + * the intent to see such events. */ - trace_printk_init_buffers(); + if (trace_set_clr_event("bpf_trace", "bpf_trace_printk", 1)) + pr_warn_ratelimited("could not enable bpf_trace_printk events"); return &bpf_trace_printk_proto; } diff --git a/kernel/trace/bpf_trace.h b/kernel/trace/bpf_trace.h new file mode 100644 index 000000000000..9acbc11ac7bb --- /dev/null +++ b/kernel/trace/bpf_trace.h @@ -0,0 +1,34 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#undef TRACE_SYSTEM +#define TRACE_SYSTEM bpf_trace + +#if !defined(_TRACE_BPF_TRACE_H) || defined(TRACE_HEADER_MULTI_READ) + +#define _TRACE_BPF_TRACE_H + +#include <linux/tracepoint.h> + +TRACE_EVENT(bpf_trace_printk, + + TP_PROTO(const char *bpf_string), + + TP_ARGS(bpf_string), + + TP_STRUCT__entry( + __string(bpf_string, bpf_string) + ), + + TP_fast_assign( + __assign_str(bpf_string, bpf_string); + ), + + TP_printk("%s", __get_str(bpf_string)) +); + +#endif /* _TRACE_BPF_TRACE_H */ + +#undef TRACE_INCLUDE_PATH +#define TRACE_INCLUDE_PATH . +#define TRACE_INCLUDE_FILE bpf_trace + +#include <trace/define_trace.h> 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 000000000000..39b0decb1bb2 --- /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 000000000000..8ca7f399b670 --- /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; +} |