bpf: Use dedicated bpf_trace_printk event instead of trace_printk() (ac5a72ea) · Commits · 戴 / test

kernel/trace/Makefile

+2 −0

Original line number	Diff line number	Diff line
		@@ -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)

kernel/trace/bpf_trace.c

+37 −5

Original line number	Diff line number	Diff line
		@@ -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;
		}

kernel/trace/bpf_trace.h

0 → 100644

+34 −0

Original line number	Diff line number	Diff line
		/* 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>

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