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![Masami Hiramatsu (Google)](/assets/img/avatar_default.png)
commitce51e6153f
upstream. Fix to check the tracepoint event is not valid with $retval. The commit08c9306fc2
("tracing/fprobe-event: Assume fprobe is a return event by $retval") introduced automatic return probe conversion with $retval. But since tracepoint event does not support return probe, $retval is not acceptable. Without this fix, ftracetest, tprobe_syntax_errors.tc fails; [22] Tracepoint probe event parser error log check [FAIL] ---- # tail 22-tprobe_syntax_errors.tc-log.mRKroL + ftrace_errlog_check trace_fprobe t kfree ^$retval dynamic_events + printf %s t kfree + wc -c + pos=8 + printf %s t kfree ^$retval + tr -d ^ + command=t kfree $retval + echo Test command: t kfree $retval Test command: t kfree $retval + echo ---- So 't kfree $retval' should fail (tracepoint doesn't support return probe) but passed it. Link: https://lore.kernel.org/all/169944555933.45057.12831706585287704173.stgit@devnote2/ Fixes:08c9306fc2
("tracing/fprobe-event: Assume fprobe is a return event by $retval") Cc: stable@vger.kernel.org Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
1231 lines
30 KiB
C
1231 lines
30 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Fprobe-based tracing events
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* Copyright (C) 2022 Google LLC.
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*/
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#define pr_fmt(fmt) "trace_fprobe: " fmt
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#include <linux/fprobe.h>
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#include <linux/module.h>
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#include <linux/rculist.h>
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#include <linux/security.h>
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#include <linux/tracepoint.h>
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#include <linux/uaccess.h>
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#include "trace_dynevent.h"
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#include "trace_probe.h"
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#include "trace_probe_kernel.h"
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#include "trace_probe_tmpl.h"
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#define FPROBE_EVENT_SYSTEM "fprobes"
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#define TRACEPOINT_EVENT_SYSTEM "tracepoints"
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#define RETHOOK_MAXACTIVE_MAX 4096
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static int trace_fprobe_create(const char *raw_command);
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static int trace_fprobe_show(struct seq_file *m, struct dyn_event *ev);
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static int trace_fprobe_release(struct dyn_event *ev);
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static bool trace_fprobe_is_busy(struct dyn_event *ev);
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static bool trace_fprobe_match(const char *system, const char *event,
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int argc, const char **argv, struct dyn_event *ev);
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static struct dyn_event_operations trace_fprobe_ops = {
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.create = trace_fprobe_create,
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.show = trace_fprobe_show,
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.is_busy = trace_fprobe_is_busy,
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.free = trace_fprobe_release,
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.match = trace_fprobe_match,
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};
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/*
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* Fprobe event core functions
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*/
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struct trace_fprobe {
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struct dyn_event devent;
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struct fprobe fp;
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const char *symbol;
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struct tracepoint *tpoint;
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struct module *mod;
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struct trace_probe tp;
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};
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static bool is_trace_fprobe(struct dyn_event *ev)
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{
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return ev->ops == &trace_fprobe_ops;
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}
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static struct trace_fprobe *to_trace_fprobe(struct dyn_event *ev)
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{
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return container_of(ev, struct trace_fprobe, devent);
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}
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/**
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* for_each_trace_fprobe - iterate over the trace_fprobe list
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* @pos: the struct trace_fprobe * for each entry
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* @dpos: the struct dyn_event * to use as a loop cursor
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*/
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#define for_each_trace_fprobe(pos, dpos) \
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for_each_dyn_event(dpos) \
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if (is_trace_fprobe(dpos) && (pos = to_trace_fprobe(dpos)))
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static bool trace_fprobe_is_return(struct trace_fprobe *tf)
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{
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return tf->fp.exit_handler != NULL;
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}
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static bool trace_fprobe_is_tracepoint(struct trace_fprobe *tf)
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{
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return tf->tpoint != NULL;
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}
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static const char *trace_fprobe_symbol(struct trace_fprobe *tf)
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{
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return tf->symbol ? tf->symbol : "unknown";
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}
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static bool trace_fprobe_is_busy(struct dyn_event *ev)
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{
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struct trace_fprobe *tf = to_trace_fprobe(ev);
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return trace_probe_is_enabled(&tf->tp);
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}
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static bool trace_fprobe_match_command_head(struct trace_fprobe *tf,
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int argc, const char **argv)
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{
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char buf[MAX_ARGSTR_LEN + 1];
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if (!argc)
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return true;
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snprintf(buf, sizeof(buf), "%s", trace_fprobe_symbol(tf));
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if (strcmp(buf, argv[0]))
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return false;
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argc--; argv++;
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return trace_probe_match_command_args(&tf->tp, argc, argv);
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}
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static bool trace_fprobe_match(const char *system, const char *event,
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int argc, const char **argv, struct dyn_event *ev)
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{
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struct trace_fprobe *tf = to_trace_fprobe(ev);
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if (event[0] != '\0' && strcmp(trace_probe_name(&tf->tp), event))
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return false;
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if (system && strcmp(trace_probe_group_name(&tf->tp), system))
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return false;
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return trace_fprobe_match_command_head(tf, argc, argv);
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}
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static bool trace_fprobe_is_registered(struct trace_fprobe *tf)
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{
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return fprobe_is_registered(&tf->fp);
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}
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/*
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* Note that we don't verify the fetch_insn code, since it does not come
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* from user space.
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*/
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static int
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process_fetch_insn(struct fetch_insn *code, void *rec, void *dest,
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void *base)
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{
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struct pt_regs *regs = rec;
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unsigned long val;
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int ret;
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retry:
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/* 1st stage: get value from context */
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switch (code->op) {
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case FETCH_OP_STACK:
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val = regs_get_kernel_stack_nth(regs, code->param);
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break;
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case FETCH_OP_STACKP:
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val = kernel_stack_pointer(regs);
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break;
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case FETCH_OP_RETVAL:
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val = regs_return_value(regs);
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break;
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#ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
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case FETCH_OP_ARG:
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val = regs_get_kernel_argument(regs, code->param);
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break;
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#endif
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case FETCH_NOP_SYMBOL: /* Ignore a place holder */
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code++;
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goto retry;
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default:
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ret = process_common_fetch_insn(code, &val);
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if (ret < 0)
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return ret;
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}
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code++;
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return process_fetch_insn_bottom(code, val, dest, base);
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}
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NOKPROBE_SYMBOL(process_fetch_insn)
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/* function entry handler */
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static nokprobe_inline void
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__fentry_trace_func(struct trace_fprobe *tf, unsigned long entry_ip,
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struct pt_regs *regs,
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struct trace_event_file *trace_file)
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{
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struct fentry_trace_entry_head *entry;
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struct trace_event_call *call = trace_probe_event_call(&tf->tp);
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struct trace_event_buffer fbuffer;
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int dsize;
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if (WARN_ON_ONCE(call != trace_file->event_call))
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return;
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if (trace_trigger_soft_disabled(trace_file))
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return;
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dsize = __get_data_size(&tf->tp, regs);
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entry = trace_event_buffer_reserve(&fbuffer, trace_file,
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sizeof(*entry) + tf->tp.size + dsize);
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if (!entry)
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return;
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fbuffer.regs = regs;
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entry = fbuffer.entry = ring_buffer_event_data(fbuffer.event);
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entry->ip = entry_ip;
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store_trace_args(&entry[1], &tf->tp, regs, sizeof(*entry), dsize);
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trace_event_buffer_commit(&fbuffer);
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}
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static void
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fentry_trace_func(struct trace_fprobe *tf, unsigned long entry_ip,
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struct pt_regs *regs)
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{
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struct event_file_link *link;
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trace_probe_for_each_link_rcu(link, &tf->tp)
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__fentry_trace_func(tf, entry_ip, regs, link->file);
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}
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NOKPROBE_SYMBOL(fentry_trace_func);
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/* Kretprobe handler */
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static nokprobe_inline void
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__fexit_trace_func(struct trace_fprobe *tf, unsigned long entry_ip,
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unsigned long ret_ip, struct pt_regs *regs,
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struct trace_event_file *trace_file)
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{
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struct fexit_trace_entry_head *entry;
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struct trace_event_buffer fbuffer;
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struct trace_event_call *call = trace_probe_event_call(&tf->tp);
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int dsize;
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if (WARN_ON_ONCE(call != trace_file->event_call))
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return;
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if (trace_trigger_soft_disabled(trace_file))
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return;
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dsize = __get_data_size(&tf->tp, regs);
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entry = trace_event_buffer_reserve(&fbuffer, trace_file,
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sizeof(*entry) + tf->tp.size + dsize);
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if (!entry)
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return;
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fbuffer.regs = regs;
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entry = fbuffer.entry = ring_buffer_event_data(fbuffer.event);
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entry->func = entry_ip;
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entry->ret_ip = ret_ip;
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store_trace_args(&entry[1], &tf->tp, regs, sizeof(*entry), dsize);
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trace_event_buffer_commit(&fbuffer);
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}
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static void
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fexit_trace_func(struct trace_fprobe *tf, unsigned long entry_ip,
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unsigned long ret_ip, struct pt_regs *regs)
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{
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struct event_file_link *link;
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trace_probe_for_each_link_rcu(link, &tf->tp)
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__fexit_trace_func(tf, entry_ip, ret_ip, regs, link->file);
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}
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NOKPROBE_SYMBOL(fexit_trace_func);
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#ifdef CONFIG_PERF_EVENTS
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static int fentry_perf_func(struct trace_fprobe *tf, unsigned long entry_ip,
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struct pt_regs *regs)
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{
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struct trace_event_call *call = trace_probe_event_call(&tf->tp);
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struct fentry_trace_entry_head *entry;
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struct hlist_head *head;
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int size, __size, dsize;
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int rctx;
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head = this_cpu_ptr(call->perf_events);
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if (hlist_empty(head))
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return 0;
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dsize = __get_data_size(&tf->tp, regs);
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__size = sizeof(*entry) + tf->tp.size + dsize;
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size = ALIGN(__size + sizeof(u32), sizeof(u64));
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size -= sizeof(u32);
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entry = perf_trace_buf_alloc(size, NULL, &rctx);
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if (!entry)
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return 0;
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entry->ip = entry_ip;
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memset(&entry[1], 0, dsize);
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store_trace_args(&entry[1], &tf->tp, regs, sizeof(*entry), dsize);
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perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
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head, NULL);
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return 0;
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}
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NOKPROBE_SYMBOL(fentry_perf_func);
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static void
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fexit_perf_func(struct trace_fprobe *tf, unsigned long entry_ip,
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unsigned long ret_ip, struct pt_regs *regs)
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{
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struct trace_event_call *call = trace_probe_event_call(&tf->tp);
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struct fexit_trace_entry_head *entry;
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struct hlist_head *head;
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int size, __size, dsize;
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int rctx;
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head = this_cpu_ptr(call->perf_events);
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if (hlist_empty(head))
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return;
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dsize = __get_data_size(&tf->tp, regs);
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__size = sizeof(*entry) + tf->tp.size + dsize;
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size = ALIGN(__size + sizeof(u32), sizeof(u64));
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size -= sizeof(u32);
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entry = perf_trace_buf_alloc(size, NULL, &rctx);
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if (!entry)
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return;
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entry->func = entry_ip;
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entry->ret_ip = ret_ip;
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store_trace_args(&entry[1], &tf->tp, regs, sizeof(*entry), dsize);
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perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
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head, NULL);
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}
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NOKPROBE_SYMBOL(fexit_perf_func);
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#endif /* CONFIG_PERF_EVENTS */
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static int fentry_dispatcher(struct fprobe *fp, unsigned long entry_ip,
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unsigned long ret_ip, struct pt_regs *regs,
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void *entry_data)
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{
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struct trace_fprobe *tf = container_of(fp, struct trace_fprobe, fp);
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int ret = 0;
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if (trace_probe_test_flag(&tf->tp, TP_FLAG_TRACE))
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fentry_trace_func(tf, entry_ip, regs);
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#ifdef CONFIG_PERF_EVENTS
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if (trace_probe_test_flag(&tf->tp, TP_FLAG_PROFILE))
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ret = fentry_perf_func(tf, entry_ip, regs);
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#endif
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return ret;
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}
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NOKPROBE_SYMBOL(fentry_dispatcher);
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static void fexit_dispatcher(struct fprobe *fp, unsigned long entry_ip,
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unsigned long ret_ip, struct pt_regs *regs,
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void *entry_data)
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{
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struct trace_fprobe *tf = container_of(fp, struct trace_fprobe, fp);
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if (trace_probe_test_flag(&tf->tp, TP_FLAG_TRACE))
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fexit_trace_func(tf, entry_ip, ret_ip, regs);
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#ifdef CONFIG_PERF_EVENTS
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if (trace_probe_test_flag(&tf->tp, TP_FLAG_PROFILE))
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fexit_perf_func(tf, entry_ip, ret_ip, regs);
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#endif
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}
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NOKPROBE_SYMBOL(fexit_dispatcher);
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static void free_trace_fprobe(struct trace_fprobe *tf)
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{
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if (tf) {
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trace_probe_cleanup(&tf->tp);
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kfree(tf->symbol);
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kfree(tf);
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}
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}
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/*
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* Allocate new trace_probe and initialize it (including fprobe).
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*/
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static struct trace_fprobe *alloc_trace_fprobe(const char *group,
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const char *event,
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const char *symbol,
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struct tracepoint *tpoint,
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int maxactive,
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int nargs, bool is_return)
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{
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struct trace_fprobe *tf;
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int ret = -ENOMEM;
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tf = kzalloc(struct_size(tf, tp.args, nargs), GFP_KERNEL);
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if (!tf)
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return ERR_PTR(ret);
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tf->symbol = kstrdup(symbol, GFP_KERNEL);
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if (!tf->symbol)
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goto error;
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if (is_return)
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tf->fp.exit_handler = fexit_dispatcher;
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else
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tf->fp.entry_handler = fentry_dispatcher;
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tf->tpoint = tpoint;
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tf->fp.nr_maxactive = maxactive;
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ret = trace_probe_init(&tf->tp, event, group, false);
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if (ret < 0)
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goto error;
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dyn_event_init(&tf->devent, &trace_fprobe_ops);
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return tf;
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error:
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free_trace_fprobe(tf);
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return ERR_PTR(ret);
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}
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static struct trace_fprobe *find_trace_fprobe(const char *event,
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const char *group)
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{
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struct dyn_event *pos;
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struct trace_fprobe *tf;
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for_each_trace_fprobe(tf, pos)
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if (strcmp(trace_probe_name(&tf->tp), event) == 0 &&
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strcmp(trace_probe_group_name(&tf->tp), group) == 0)
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return tf;
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return NULL;
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}
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static inline int __enable_trace_fprobe(struct trace_fprobe *tf)
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{
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if (trace_fprobe_is_registered(tf))
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enable_fprobe(&tf->fp);
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return 0;
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}
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static void __disable_trace_fprobe(struct trace_probe *tp)
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{
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struct trace_fprobe *tf;
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list_for_each_entry(tf, trace_probe_probe_list(tp), tp.list) {
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if (!trace_fprobe_is_registered(tf))
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continue;
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disable_fprobe(&tf->fp);
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}
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}
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|
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/*
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* Enable trace_probe
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* if the file is NULL, enable "perf" handler, or enable "trace" handler.
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*/
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static int enable_trace_fprobe(struct trace_event_call *call,
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struct trace_event_file *file)
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{
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struct trace_probe *tp;
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struct trace_fprobe *tf;
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bool enabled;
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int ret = 0;
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tp = trace_probe_primary_from_call(call);
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if (WARN_ON_ONCE(!tp))
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return -ENODEV;
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enabled = trace_probe_is_enabled(tp);
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|
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/* This also changes "enabled" state */
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if (file) {
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ret = trace_probe_add_file(tp, file);
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if (ret)
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return ret;
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} else
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trace_probe_set_flag(tp, TP_FLAG_PROFILE);
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|
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if (!enabled) {
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list_for_each_entry(tf, trace_probe_probe_list(tp), tp.list) {
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/* TODO: check the fprobe is gone */
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__enable_trace_fprobe(tf);
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}
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}
|
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return 0;
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}
|
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|
|
/*
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* Disable trace_probe
|
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* if the file is NULL, disable "perf" handler, or disable "trace" handler.
|
|
*/
|
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static int disable_trace_fprobe(struct trace_event_call *call,
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struct trace_event_file *file)
|
|
{
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struct trace_probe *tp;
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|
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tp = trace_probe_primary_from_call(call);
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if (WARN_ON_ONCE(!tp))
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return -ENODEV;
|
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|
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if (file) {
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if (!trace_probe_get_file_link(tp, file))
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return -ENOENT;
|
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if (!trace_probe_has_single_file(tp))
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goto out;
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trace_probe_clear_flag(tp, TP_FLAG_TRACE);
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} else
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trace_probe_clear_flag(tp, TP_FLAG_PROFILE);
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|
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if (!trace_probe_is_enabled(tp))
|
|
__disable_trace_fprobe(tp);
|
|
|
|
out:
|
|
if (file)
|
|
/*
|
|
* Synchronization is done in below function. For perf event,
|
|
* file == NULL and perf_trace_event_unreg() calls
|
|
* tracepoint_synchronize_unregister() to ensure synchronize
|
|
* event. We don't need to care about it.
|
|
*/
|
|
trace_probe_remove_file(tp, file);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/* Event entry printers */
|
|
static enum print_line_t
|
|
print_fentry_event(struct trace_iterator *iter, int flags,
|
|
struct trace_event *event)
|
|
{
|
|
struct fentry_trace_entry_head *field;
|
|
struct trace_seq *s = &iter->seq;
|
|
struct trace_probe *tp;
|
|
|
|
field = (struct fentry_trace_entry_head *)iter->ent;
|
|
tp = trace_probe_primary_from_call(
|
|
container_of(event, struct trace_event_call, event));
|
|
if (WARN_ON_ONCE(!tp))
|
|
goto out;
|
|
|
|
trace_seq_printf(s, "%s: (", trace_probe_name(tp));
|
|
|
|
if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET))
|
|
goto out;
|
|
|
|
trace_seq_putc(s, ')');
|
|
|
|
if (trace_probe_print_args(s, tp->args, tp->nr_args,
|
|
(u8 *)&field[1], field) < 0)
|
|
goto out;
|
|
|
|
trace_seq_putc(s, '\n');
|
|
out:
|
|
return trace_handle_return(s);
|
|
}
|
|
|
|
static enum print_line_t
|
|
print_fexit_event(struct trace_iterator *iter, int flags,
|
|
struct trace_event *event)
|
|
{
|
|
struct fexit_trace_entry_head *field;
|
|
struct trace_seq *s = &iter->seq;
|
|
struct trace_probe *tp;
|
|
|
|
field = (struct fexit_trace_entry_head *)iter->ent;
|
|
tp = trace_probe_primary_from_call(
|
|
container_of(event, struct trace_event_call, event));
|
|
if (WARN_ON_ONCE(!tp))
|
|
goto out;
|
|
|
|
trace_seq_printf(s, "%s: (", trace_probe_name(tp));
|
|
|
|
if (!seq_print_ip_sym(s, field->ret_ip, flags | TRACE_ITER_SYM_OFFSET))
|
|
goto out;
|
|
|
|
trace_seq_puts(s, " <- ");
|
|
|
|
if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET))
|
|
goto out;
|
|
|
|
trace_seq_putc(s, ')');
|
|
|
|
if (trace_probe_print_args(s, tp->args, tp->nr_args,
|
|
(u8 *)&field[1], field) < 0)
|
|
goto out;
|
|
|
|
trace_seq_putc(s, '\n');
|
|
|
|
out:
|
|
return trace_handle_return(s);
|
|
}
|
|
|
|
static int fentry_event_define_fields(struct trace_event_call *event_call)
|
|
{
|
|
int ret;
|
|
struct fentry_trace_entry_head field;
|
|
struct trace_probe *tp;
|
|
|
|
tp = trace_probe_primary_from_call(event_call);
|
|
if (WARN_ON_ONCE(!tp))
|
|
return -ENOENT;
|
|
|
|
DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0);
|
|
|
|
return traceprobe_define_arg_fields(event_call, sizeof(field), tp);
|
|
}
|
|
|
|
static int fexit_event_define_fields(struct trace_event_call *event_call)
|
|
{
|
|
int ret;
|
|
struct fexit_trace_entry_head field;
|
|
struct trace_probe *tp;
|
|
|
|
tp = trace_probe_primary_from_call(event_call);
|
|
if (WARN_ON_ONCE(!tp))
|
|
return -ENOENT;
|
|
|
|
DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0);
|
|
DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0);
|
|
|
|
return traceprobe_define_arg_fields(event_call, sizeof(field), tp);
|
|
}
|
|
|
|
static struct trace_event_functions fentry_funcs = {
|
|
.trace = print_fentry_event
|
|
};
|
|
|
|
static struct trace_event_functions fexit_funcs = {
|
|
.trace = print_fexit_event
|
|
};
|
|
|
|
static struct trace_event_fields fentry_fields_array[] = {
|
|
{ .type = TRACE_FUNCTION_TYPE,
|
|
.define_fields = fentry_event_define_fields },
|
|
{}
|
|
};
|
|
|
|
static struct trace_event_fields fexit_fields_array[] = {
|
|
{ .type = TRACE_FUNCTION_TYPE,
|
|
.define_fields = fexit_event_define_fields },
|
|
{}
|
|
};
|
|
|
|
static int fprobe_register(struct trace_event_call *event,
|
|
enum trace_reg type, void *data);
|
|
|
|
static inline void init_trace_event_call(struct trace_fprobe *tf)
|
|
{
|
|
struct trace_event_call *call = trace_probe_event_call(&tf->tp);
|
|
|
|
if (trace_fprobe_is_return(tf)) {
|
|
call->event.funcs = &fexit_funcs;
|
|
call->class->fields_array = fexit_fields_array;
|
|
} else {
|
|
call->event.funcs = &fentry_funcs;
|
|
call->class->fields_array = fentry_fields_array;
|
|
}
|
|
|
|
call->flags = TRACE_EVENT_FL_FPROBE;
|
|
call->class->reg = fprobe_register;
|
|
}
|
|
|
|
static int register_fprobe_event(struct trace_fprobe *tf)
|
|
{
|
|
init_trace_event_call(tf);
|
|
|
|
return trace_probe_register_event_call(&tf->tp);
|
|
}
|
|
|
|
static int unregister_fprobe_event(struct trace_fprobe *tf)
|
|
{
|
|
return trace_probe_unregister_event_call(&tf->tp);
|
|
}
|
|
|
|
/* Internal register function - just handle fprobe and flags */
|
|
static int __register_trace_fprobe(struct trace_fprobe *tf)
|
|
{
|
|
int i, ret;
|
|
|
|
/* Should we need new LOCKDOWN flag for fprobe? */
|
|
ret = security_locked_down(LOCKDOWN_KPROBES);
|
|
if (ret)
|
|
return ret;
|
|
|
|
if (trace_fprobe_is_registered(tf))
|
|
return -EINVAL;
|
|
|
|
for (i = 0; i < tf->tp.nr_args; i++) {
|
|
ret = traceprobe_update_arg(&tf->tp.args[i]);
|
|
if (ret)
|
|
return ret;
|
|
}
|
|
|
|
/* Set/clear disabled flag according to tp->flag */
|
|
if (trace_probe_is_enabled(&tf->tp))
|
|
tf->fp.flags &= ~FPROBE_FL_DISABLED;
|
|
else
|
|
tf->fp.flags |= FPROBE_FL_DISABLED;
|
|
|
|
if (trace_fprobe_is_tracepoint(tf)) {
|
|
struct tracepoint *tpoint = tf->tpoint;
|
|
unsigned long ip = (unsigned long)tpoint->probestub;
|
|
/*
|
|
* Here, we do 2 steps to enable fprobe on a tracepoint.
|
|
* At first, put __probestub_##TP function on the tracepoint
|
|
* and put a fprobe on the stub function.
|
|
*/
|
|
ret = tracepoint_probe_register_prio_may_exist(tpoint,
|
|
tpoint->probestub, NULL, 0);
|
|
if (ret < 0)
|
|
return ret;
|
|
return register_fprobe_ips(&tf->fp, &ip, 1);
|
|
}
|
|
|
|
/* TODO: handle filter, nofilter or symbol list */
|
|
return register_fprobe(&tf->fp, tf->symbol, NULL);
|
|
}
|
|
|
|
/* Internal unregister function - just handle fprobe and flags */
|
|
static void __unregister_trace_fprobe(struct trace_fprobe *tf)
|
|
{
|
|
if (trace_fprobe_is_registered(tf)) {
|
|
unregister_fprobe(&tf->fp);
|
|
memset(&tf->fp, 0, sizeof(tf->fp));
|
|
if (trace_fprobe_is_tracepoint(tf)) {
|
|
tracepoint_probe_unregister(tf->tpoint,
|
|
tf->tpoint->probestub, NULL);
|
|
tf->tpoint = NULL;
|
|
tf->mod = NULL;
|
|
}
|
|
}
|
|
}
|
|
|
|
/* TODO: make this trace_*probe common function */
|
|
/* Unregister a trace_probe and probe_event */
|
|
static int unregister_trace_fprobe(struct trace_fprobe *tf)
|
|
{
|
|
/* If other probes are on the event, just unregister fprobe */
|
|
if (trace_probe_has_sibling(&tf->tp))
|
|
goto unreg;
|
|
|
|
/* Enabled event can not be unregistered */
|
|
if (trace_probe_is_enabled(&tf->tp))
|
|
return -EBUSY;
|
|
|
|
/* If there's a reference to the dynamic event */
|
|
if (trace_event_dyn_busy(trace_probe_event_call(&tf->tp)))
|
|
return -EBUSY;
|
|
|
|
/* Will fail if probe is being used by ftrace or perf */
|
|
if (unregister_fprobe_event(tf))
|
|
return -EBUSY;
|
|
|
|
unreg:
|
|
__unregister_trace_fprobe(tf);
|
|
dyn_event_remove(&tf->devent);
|
|
trace_probe_unlink(&tf->tp);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static bool trace_fprobe_has_same_fprobe(struct trace_fprobe *orig,
|
|
struct trace_fprobe *comp)
|
|
{
|
|
struct trace_probe_event *tpe = orig->tp.event;
|
|
int i;
|
|
|
|
list_for_each_entry(orig, &tpe->probes, tp.list) {
|
|
if (strcmp(trace_fprobe_symbol(orig),
|
|
trace_fprobe_symbol(comp)))
|
|
continue;
|
|
|
|
/*
|
|
* trace_probe_compare_arg_type() ensured that nr_args and
|
|
* each argument name and type are same. Let's compare comm.
|
|
*/
|
|
for (i = 0; i < orig->tp.nr_args; i++) {
|
|
if (strcmp(orig->tp.args[i].comm,
|
|
comp->tp.args[i].comm))
|
|
break;
|
|
}
|
|
|
|
if (i == orig->tp.nr_args)
|
|
return true;
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
static int append_trace_fprobe(struct trace_fprobe *tf, struct trace_fprobe *to)
|
|
{
|
|
int ret;
|
|
|
|
if (trace_fprobe_is_return(tf) != trace_fprobe_is_return(to) ||
|
|
trace_fprobe_is_tracepoint(tf) != trace_fprobe_is_tracepoint(to)) {
|
|
trace_probe_log_set_index(0);
|
|
trace_probe_log_err(0, DIFF_PROBE_TYPE);
|
|
return -EEXIST;
|
|
}
|
|
ret = trace_probe_compare_arg_type(&tf->tp, &to->tp);
|
|
if (ret) {
|
|
/* Note that argument starts index = 2 */
|
|
trace_probe_log_set_index(ret + 1);
|
|
trace_probe_log_err(0, DIFF_ARG_TYPE);
|
|
return -EEXIST;
|
|
}
|
|
if (trace_fprobe_has_same_fprobe(to, tf)) {
|
|
trace_probe_log_set_index(0);
|
|
trace_probe_log_err(0, SAME_PROBE);
|
|
return -EEXIST;
|
|
}
|
|
|
|
/* Append to existing event */
|
|
ret = trace_probe_append(&tf->tp, &to->tp);
|
|
if (ret)
|
|
return ret;
|
|
|
|
ret = __register_trace_fprobe(tf);
|
|
if (ret)
|
|
trace_probe_unlink(&tf->tp);
|
|
else
|
|
dyn_event_add(&tf->devent, trace_probe_event_call(&tf->tp));
|
|
|
|
return ret;
|
|
}
|
|
|
|
/* Register a trace_probe and probe_event */
|
|
static int register_trace_fprobe(struct trace_fprobe *tf)
|
|
{
|
|
struct trace_fprobe *old_tf;
|
|
int ret;
|
|
|
|
mutex_lock(&event_mutex);
|
|
|
|
old_tf = find_trace_fprobe(trace_probe_name(&tf->tp),
|
|
trace_probe_group_name(&tf->tp));
|
|
if (old_tf) {
|
|
ret = append_trace_fprobe(tf, old_tf);
|
|
goto end;
|
|
}
|
|
|
|
/* Register new event */
|
|
ret = register_fprobe_event(tf);
|
|
if (ret) {
|
|
if (ret == -EEXIST) {
|
|
trace_probe_log_set_index(0);
|
|
trace_probe_log_err(0, EVENT_EXIST);
|
|
} else
|
|
pr_warn("Failed to register probe event(%d)\n", ret);
|
|
goto end;
|
|
}
|
|
|
|
/* Register fprobe */
|
|
ret = __register_trace_fprobe(tf);
|
|
if (ret < 0)
|
|
unregister_fprobe_event(tf);
|
|
else
|
|
dyn_event_add(&tf->devent, trace_probe_event_call(&tf->tp));
|
|
|
|
end:
|
|
mutex_unlock(&event_mutex);
|
|
return ret;
|
|
}
|
|
|
|
#ifdef CONFIG_MODULES
|
|
static int __tracepoint_probe_module_cb(struct notifier_block *self,
|
|
unsigned long val, void *data)
|
|
{
|
|
struct tp_module *tp_mod = data;
|
|
struct trace_fprobe *tf;
|
|
struct dyn_event *pos;
|
|
|
|
if (val != MODULE_STATE_GOING)
|
|
return NOTIFY_DONE;
|
|
|
|
mutex_lock(&event_mutex);
|
|
for_each_trace_fprobe(tf, pos) {
|
|
if (tp_mod->mod == tf->mod) {
|
|
tracepoint_probe_unregister(tf->tpoint,
|
|
tf->tpoint->probestub, NULL);
|
|
tf->tpoint = NULL;
|
|
tf->mod = NULL;
|
|
}
|
|
}
|
|
mutex_unlock(&event_mutex);
|
|
|
|
return NOTIFY_DONE;
|
|
}
|
|
|
|
static struct notifier_block tracepoint_module_nb = {
|
|
.notifier_call = __tracepoint_probe_module_cb,
|
|
};
|
|
#endif /* CONFIG_MODULES */
|
|
|
|
struct __find_tracepoint_cb_data {
|
|
const char *tp_name;
|
|
struct tracepoint *tpoint;
|
|
};
|
|
|
|
static void __find_tracepoint_cb(struct tracepoint *tp, void *priv)
|
|
{
|
|
struct __find_tracepoint_cb_data *data = priv;
|
|
|
|
if (!data->tpoint && !strcmp(data->tp_name, tp->name))
|
|
data->tpoint = tp;
|
|
}
|
|
|
|
static struct tracepoint *find_tracepoint(const char *tp_name)
|
|
{
|
|
struct __find_tracepoint_cb_data data = {
|
|
.tp_name = tp_name,
|
|
};
|
|
|
|
for_each_kernel_tracepoint(__find_tracepoint_cb, &data);
|
|
|
|
return data.tpoint;
|
|
}
|
|
|
|
static int parse_symbol_and_return(int argc, const char *argv[],
|
|
char **symbol, bool *is_return,
|
|
bool is_tracepoint)
|
|
{
|
|
char *tmp = strchr(argv[1], '%');
|
|
int i;
|
|
|
|
if (tmp) {
|
|
int len = tmp - argv[1];
|
|
|
|
if (!is_tracepoint && !strcmp(tmp, "%return")) {
|
|
*is_return = true;
|
|
} else {
|
|
trace_probe_log_err(len, BAD_ADDR_SUFFIX);
|
|
return -EINVAL;
|
|
}
|
|
*symbol = kmemdup_nul(argv[1], len, GFP_KERNEL);
|
|
} else
|
|
*symbol = kstrdup(argv[1], GFP_KERNEL);
|
|
if (!*symbol)
|
|
return -ENOMEM;
|
|
|
|
if (*is_return)
|
|
return 0;
|
|
|
|
/* If there is $retval, this should be a return fprobe. */
|
|
for (i = 2; i < argc; i++) {
|
|
tmp = strstr(argv[i], "$retval");
|
|
if (tmp && !isalnum(tmp[7]) && tmp[7] != '_') {
|
|
if (is_tracepoint) {
|
|
trace_probe_log_set_index(i);
|
|
trace_probe_log_err(tmp - argv[i], RETVAL_ON_PROBE);
|
|
return -EINVAL;
|
|
}
|
|
*is_return = true;
|
|
break;
|
|
}
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static int __trace_fprobe_create(int argc, const char *argv[])
|
|
{
|
|
/*
|
|
* Argument syntax:
|
|
* - Add fentry probe:
|
|
* f[:[GRP/][EVENT]] [MOD:]KSYM [FETCHARGS]
|
|
* - Add fexit probe:
|
|
* f[N][:[GRP/][EVENT]] [MOD:]KSYM%return [FETCHARGS]
|
|
* - Add tracepoint probe:
|
|
* t[:[GRP/][EVENT]] TRACEPOINT [FETCHARGS]
|
|
*
|
|
* Fetch args:
|
|
* $retval : fetch return value
|
|
* $stack : fetch stack address
|
|
* $stackN : fetch Nth entry of stack (N:0-)
|
|
* $argN : fetch Nth argument (N:1-)
|
|
* $comm : fetch current task comm
|
|
* @ADDR : fetch memory at ADDR (ADDR should be in kernel)
|
|
* @SYM[+|-offs] : fetch memory at SYM +|- offs (SYM is a data symbol)
|
|
* Dereferencing memory fetch:
|
|
* +|-offs(ARG) : fetch memory at ARG +|- offs address.
|
|
* Alias name of args:
|
|
* NAME=FETCHARG : set NAME as alias of FETCHARG.
|
|
* Type of args:
|
|
* FETCHARG:TYPE : use TYPE instead of unsigned long.
|
|
*/
|
|
struct trace_fprobe *tf = NULL;
|
|
int i, len, new_argc = 0, ret = 0;
|
|
bool is_return = false;
|
|
char *symbol = NULL;
|
|
const char *event = NULL, *group = FPROBE_EVENT_SYSTEM;
|
|
const char **new_argv = NULL;
|
|
int maxactive = 0;
|
|
char buf[MAX_EVENT_NAME_LEN];
|
|
char gbuf[MAX_EVENT_NAME_LEN];
|
|
char sbuf[KSYM_NAME_LEN];
|
|
char abuf[MAX_BTF_ARGS_LEN];
|
|
bool is_tracepoint = false;
|
|
struct tracepoint *tpoint = NULL;
|
|
struct traceprobe_parse_context ctx = {
|
|
.flags = TPARG_FL_KERNEL | TPARG_FL_FPROBE,
|
|
};
|
|
|
|
if ((argv[0][0] != 'f' && argv[0][0] != 't') || argc < 2)
|
|
return -ECANCELED;
|
|
|
|
if (argv[0][0] == 't') {
|
|
is_tracepoint = true;
|
|
group = TRACEPOINT_EVENT_SYSTEM;
|
|
}
|
|
|
|
trace_probe_log_init("trace_fprobe", argc, argv);
|
|
|
|
event = strchr(&argv[0][1], ':');
|
|
if (event)
|
|
event++;
|
|
|
|
if (isdigit(argv[0][1])) {
|
|
if (event)
|
|
len = event - &argv[0][1] - 1;
|
|
else
|
|
len = strlen(&argv[0][1]);
|
|
if (len > MAX_EVENT_NAME_LEN - 1) {
|
|
trace_probe_log_err(1, BAD_MAXACT);
|
|
goto parse_error;
|
|
}
|
|
memcpy(buf, &argv[0][1], len);
|
|
buf[len] = '\0';
|
|
ret = kstrtouint(buf, 0, &maxactive);
|
|
if (ret || !maxactive) {
|
|
trace_probe_log_err(1, BAD_MAXACT);
|
|
goto parse_error;
|
|
}
|
|
/* fprobe rethook instances are iterated over via a list. The
|
|
* maximum should stay reasonable.
|
|
*/
|
|
if (maxactive > RETHOOK_MAXACTIVE_MAX) {
|
|
trace_probe_log_err(1, MAXACT_TOO_BIG);
|
|
goto parse_error;
|
|
}
|
|
}
|
|
|
|
trace_probe_log_set_index(1);
|
|
|
|
/* a symbol(or tracepoint) must be specified */
|
|
ret = parse_symbol_and_return(argc, argv, &symbol, &is_return, is_tracepoint);
|
|
if (ret < 0)
|
|
goto parse_error;
|
|
|
|
if (!is_return && maxactive) {
|
|
trace_probe_log_set_index(0);
|
|
trace_probe_log_err(1, BAD_MAXACT_TYPE);
|
|
goto parse_error;
|
|
}
|
|
|
|
trace_probe_log_set_index(0);
|
|
if (event) {
|
|
ret = traceprobe_parse_event_name(&event, &group, gbuf,
|
|
event - argv[0]);
|
|
if (ret)
|
|
goto parse_error;
|
|
}
|
|
|
|
if (!event) {
|
|
/* Make a new event name */
|
|
if (is_tracepoint)
|
|
snprintf(buf, MAX_EVENT_NAME_LEN, "%s%s",
|
|
isdigit(*symbol) ? "_" : "", symbol);
|
|
else
|
|
snprintf(buf, MAX_EVENT_NAME_LEN, "%s__%s", symbol,
|
|
is_return ? "exit" : "entry");
|
|
sanitize_event_name(buf);
|
|
event = buf;
|
|
}
|
|
|
|
if (is_return)
|
|
ctx.flags |= TPARG_FL_RETURN;
|
|
else
|
|
ctx.flags |= TPARG_FL_FENTRY;
|
|
|
|
if (is_tracepoint) {
|
|
ctx.flags |= TPARG_FL_TPOINT;
|
|
tpoint = find_tracepoint(symbol);
|
|
if (!tpoint) {
|
|
trace_probe_log_set_index(1);
|
|
trace_probe_log_err(0, NO_TRACEPOINT);
|
|
goto parse_error;
|
|
}
|
|
ctx.funcname = kallsyms_lookup(
|
|
(unsigned long)tpoint->probestub,
|
|
NULL, NULL, NULL, sbuf);
|
|
} else
|
|
ctx.funcname = symbol;
|
|
|
|
argc -= 2; argv += 2;
|
|
new_argv = traceprobe_expand_meta_args(argc, argv, &new_argc,
|
|
abuf, MAX_BTF_ARGS_LEN, &ctx);
|
|
if (IS_ERR(new_argv)) {
|
|
ret = PTR_ERR(new_argv);
|
|
new_argv = NULL;
|
|
goto out;
|
|
}
|
|
if (new_argv) {
|
|
argc = new_argc;
|
|
argv = new_argv;
|
|
}
|
|
|
|
/* setup a probe */
|
|
tf = alloc_trace_fprobe(group, event, symbol, tpoint, maxactive,
|
|
argc, is_return);
|
|
if (IS_ERR(tf)) {
|
|
ret = PTR_ERR(tf);
|
|
/* This must return -ENOMEM, else there is a bug */
|
|
WARN_ON_ONCE(ret != -ENOMEM);
|
|
goto out; /* We know tf is not allocated */
|
|
}
|
|
|
|
if (is_tracepoint)
|
|
tf->mod = __module_text_address(
|
|
(unsigned long)tf->tpoint->probestub);
|
|
|
|
/* parse arguments */
|
|
for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
|
|
trace_probe_log_set_index(i + 2);
|
|
ctx.offset = 0;
|
|
ret = traceprobe_parse_probe_arg(&tf->tp, i, argv[i], &ctx);
|
|
if (ret)
|
|
goto error; /* This can be -ENOMEM */
|
|
}
|
|
|
|
ret = traceprobe_set_print_fmt(&tf->tp,
|
|
is_return ? PROBE_PRINT_RETURN : PROBE_PRINT_NORMAL);
|
|
if (ret < 0)
|
|
goto error;
|
|
|
|
ret = register_trace_fprobe(tf);
|
|
if (ret) {
|
|
trace_probe_log_set_index(1);
|
|
if (ret == -EILSEQ)
|
|
trace_probe_log_err(0, BAD_INSN_BNDRY);
|
|
else if (ret == -ENOENT)
|
|
trace_probe_log_err(0, BAD_PROBE_ADDR);
|
|
else if (ret != -ENOMEM && ret != -EEXIST)
|
|
trace_probe_log_err(0, FAIL_REG_PROBE);
|
|
goto error;
|
|
}
|
|
|
|
out:
|
|
traceprobe_finish_parse(&ctx);
|
|
trace_probe_log_clear();
|
|
kfree(new_argv);
|
|
kfree(symbol);
|
|
return ret;
|
|
|
|
parse_error:
|
|
ret = -EINVAL;
|
|
error:
|
|
free_trace_fprobe(tf);
|
|
goto out;
|
|
}
|
|
|
|
static int trace_fprobe_create(const char *raw_command)
|
|
{
|
|
return trace_probe_create(raw_command, __trace_fprobe_create);
|
|
}
|
|
|
|
static int trace_fprobe_release(struct dyn_event *ev)
|
|
{
|
|
struct trace_fprobe *tf = to_trace_fprobe(ev);
|
|
int ret = unregister_trace_fprobe(tf);
|
|
|
|
if (!ret)
|
|
free_trace_fprobe(tf);
|
|
return ret;
|
|
}
|
|
|
|
static int trace_fprobe_show(struct seq_file *m, struct dyn_event *ev)
|
|
{
|
|
struct trace_fprobe *tf = to_trace_fprobe(ev);
|
|
int i;
|
|
|
|
if (trace_fprobe_is_tracepoint(tf))
|
|
seq_putc(m, 't');
|
|
else
|
|
seq_putc(m, 'f');
|
|
if (trace_fprobe_is_return(tf) && tf->fp.nr_maxactive)
|
|
seq_printf(m, "%d", tf->fp.nr_maxactive);
|
|
seq_printf(m, ":%s/%s", trace_probe_group_name(&tf->tp),
|
|
trace_probe_name(&tf->tp));
|
|
|
|
seq_printf(m, " %s%s", trace_fprobe_symbol(tf),
|
|
trace_fprobe_is_return(tf) ? "%return" : "");
|
|
|
|
for (i = 0; i < tf->tp.nr_args; i++)
|
|
seq_printf(m, " %s=%s", tf->tp.args[i].name, tf->tp.args[i].comm);
|
|
seq_putc(m, '\n');
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* called by perf_trace_init() or __ftrace_set_clr_event() under event_mutex.
|
|
*/
|
|
static int fprobe_register(struct trace_event_call *event,
|
|
enum trace_reg type, void *data)
|
|
{
|
|
struct trace_event_file *file = data;
|
|
|
|
switch (type) {
|
|
case TRACE_REG_REGISTER:
|
|
return enable_trace_fprobe(event, file);
|
|
case TRACE_REG_UNREGISTER:
|
|
return disable_trace_fprobe(event, file);
|
|
|
|
#ifdef CONFIG_PERF_EVENTS
|
|
case TRACE_REG_PERF_REGISTER:
|
|
return enable_trace_fprobe(event, NULL);
|
|
case TRACE_REG_PERF_UNREGISTER:
|
|
return disable_trace_fprobe(event, NULL);
|
|
case TRACE_REG_PERF_OPEN:
|
|
case TRACE_REG_PERF_CLOSE:
|
|
case TRACE_REG_PERF_ADD:
|
|
case TRACE_REG_PERF_DEL:
|
|
return 0;
|
|
#endif
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Register dynevent at core_initcall. This allows kernel to setup fprobe
|
|
* events in postcore_initcall without tracefs.
|
|
*/
|
|
static __init int init_fprobe_trace_early(void)
|
|
{
|
|
int ret;
|
|
|
|
ret = dyn_event_register(&trace_fprobe_ops);
|
|
if (ret)
|
|
return ret;
|
|
|
|
#ifdef CONFIG_MODULES
|
|
ret = register_tracepoint_module_notifier(&tracepoint_module_nb);
|
|
if (ret)
|
|
return ret;
|
|
#endif
|
|
|
|
return 0;
|
|
}
|
|
core_initcall(init_fprobe_trace_early);
|