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![Linus Torvalds](/assets/img/avatar_default.png)
from being traced by kprobes. During my testing, I found that there's places that we may want to add kprobes to notrace, thus we may end up changing this code before 4.19 is released. The history behind this change is that we found that adding kprobes to various notrace functions caused the kernel to crashed. We took the safe route and decided not to allow kprobes to trace any notrace function. But because notrace is added to functions that just cause weird side effects to the function tracer, but are still safe, preventing kprobes for all notrace functios may be too much of a big hammer. One such place is __schedule() is marked notrace, to keep function tracer from doing strange recursive loops when it gets traced with NEED_RESCHED set. With this change, one can not add kprobes to the scheduler. Masami also added code to use gcov on ftrace. -----BEGIN PGP SIGNATURE----- iIoEABYIADIWIQRRSw7ePDh/lE+zeZMp5XQQmuv6qgUCW34RpBQccm9zdGVkdEBn b29kbWlzLm9yZwAKCRAp5XQQmuv6qhwzAQDITRob1VjOF8RavMbfBZZuhwHPQROF XsIFcD+jghFOUgEA1zXX4w+SwOV7S+chpGKMh3DlNKIbYPA+8eiMNFfDsA4= =u+oq -----END PGP SIGNATURE----- Merge tag 'trace-v4.19-1' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace Pull tracing fixes from Steven Rostedt: "Masami found an off by one bug in the code that keeps "notrace" functions from being traced by kprobes. During my testing, I found that there's places that we may want to add kprobes to notrace, thus we may end up changing this code before 4.19 is released. The history behind this change is that we found that adding kprobes to various notrace functions caused the kernel to crashed. We took the safe route and decided not to allow kprobes to trace any notrace function. But because notrace is added to functions that just cause weird side effects to the function tracer, but are still safe, preventing kprobes for all notrace functios may be too much of a big hammer. One such place is __schedule() is marked notrace, to keep function tracer from doing strange recursive loops when it gets traced with NEED_RESCHED set. With this change, one can not add kprobes to the scheduler. Masami also added code to use gcov on ftrace" * tag 'trace-v4.19-1' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: tracing/kprobes: Fix to check notrace function with correct range tracing: Allow gcov profiling on only ftrace subsystem
1735 lines
42 KiB
C
1735 lines
42 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Kprobes-based tracing events
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*
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* Created by Masami Hiramatsu <mhiramat@redhat.com>
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*
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*/
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#define pr_fmt(fmt) "trace_kprobe: " fmt
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#include <linux/module.h>
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#include <linux/uaccess.h>
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#include <linux/rculist.h>
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#include <linux/error-injection.h>
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#include "trace_kprobe_selftest.h"
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#include "trace_probe.h"
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#define KPROBE_EVENT_SYSTEM "kprobes"
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#define KRETPROBE_MAXACTIVE_MAX 4096
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/**
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* Kprobe event core functions
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*/
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struct trace_kprobe {
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struct list_head list;
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struct kretprobe rp; /* Use rp.kp for kprobe use */
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unsigned long __percpu *nhit;
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const char *symbol; /* symbol name */
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struct trace_probe tp;
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};
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#define SIZEOF_TRACE_KPROBE(n) \
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(offsetof(struct trace_kprobe, tp.args) + \
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(sizeof(struct probe_arg) * (n)))
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static nokprobe_inline bool trace_kprobe_is_return(struct trace_kprobe *tk)
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{
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return tk->rp.handler != NULL;
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}
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static nokprobe_inline const char *trace_kprobe_symbol(struct trace_kprobe *tk)
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{
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return tk->symbol ? tk->symbol : "unknown";
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}
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static nokprobe_inline unsigned long trace_kprobe_offset(struct trace_kprobe *tk)
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{
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return tk->rp.kp.offset;
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}
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static nokprobe_inline bool trace_kprobe_has_gone(struct trace_kprobe *tk)
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{
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return !!(kprobe_gone(&tk->rp.kp));
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}
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static nokprobe_inline bool trace_kprobe_within_module(struct trace_kprobe *tk,
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struct module *mod)
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{
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int len = strlen(mod->name);
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const char *name = trace_kprobe_symbol(tk);
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return strncmp(mod->name, name, len) == 0 && name[len] == ':';
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}
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static nokprobe_inline bool trace_kprobe_is_on_module(struct trace_kprobe *tk)
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{
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return !!strchr(trace_kprobe_symbol(tk), ':');
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}
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static nokprobe_inline unsigned long trace_kprobe_nhit(struct trace_kprobe *tk)
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{
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unsigned long nhit = 0;
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int cpu;
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for_each_possible_cpu(cpu)
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nhit += *per_cpu_ptr(tk->nhit, cpu);
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return nhit;
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}
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/* Return 0 if it fails to find the symbol address */
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static nokprobe_inline
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unsigned long trace_kprobe_address(struct trace_kprobe *tk)
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{
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unsigned long addr;
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if (tk->symbol) {
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addr = (unsigned long)
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kallsyms_lookup_name(trace_kprobe_symbol(tk));
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if (addr)
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addr += tk->rp.kp.offset;
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} else {
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addr = (unsigned long)tk->rp.kp.addr;
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}
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return addr;
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}
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bool trace_kprobe_on_func_entry(struct trace_event_call *call)
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{
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struct trace_kprobe *tk = (struct trace_kprobe *)call->data;
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return kprobe_on_func_entry(tk->rp.kp.addr,
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tk->rp.kp.addr ? NULL : tk->rp.kp.symbol_name,
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tk->rp.kp.addr ? 0 : tk->rp.kp.offset);
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}
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bool trace_kprobe_error_injectable(struct trace_event_call *call)
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{
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struct trace_kprobe *tk = (struct trace_kprobe *)call->data;
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return within_error_injection_list(trace_kprobe_address(tk));
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}
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static int register_kprobe_event(struct trace_kprobe *tk);
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static int unregister_kprobe_event(struct trace_kprobe *tk);
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static DEFINE_MUTEX(probe_lock);
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static LIST_HEAD(probe_list);
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static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs);
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static int kretprobe_dispatcher(struct kretprobe_instance *ri,
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struct pt_regs *regs);
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/* Memory fetching by symbol */
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struct symbol_cache {
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char *symbol;
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long offset;
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unsigned long addr;
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};
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unsigned long update_symbol_cache(struct symbol_cache *sc)
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{
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sc->addr = (unsigned long)kallsyms_lookup_name(sc->symbol);
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if (sc->addr)
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sc->addr += sc->offset;
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return sc->addr;
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}
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void free_symbol_cache(struct symbol_cache *sc)
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{
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kfree(sc->symbol);
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kfree(sc);
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}
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struct symbol_cache *alloc_symbol_cache(const char *sym, long offset)
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{
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struct symbol_cache *sc;
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if (!sym || strlen(sym) == 0)
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return NULL;
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sc = kzalloc(sizeof(struct symbol_cache), GFP_KERNEL);
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if (!sc)
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return NULL;
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sc->symbol = kstrdup(sym, GFP_KERNEL);
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if (!sc->symbol) {
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kfree(sc);
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return NULL;
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}
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sc->offset = offset;
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update_symbol_cache(sc);
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return sc;
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}
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/*
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* Kprobes-specific fetch functions
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*/
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#define DEFINE_FETCH_stack(type) \
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static void FETCH_FUNC_NAME(stack, type)(struct pt_regs *regs, \
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void *offset, void *dest) \
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{ \
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*(type *)dest = (type)regs_get_kernel_stack_nth(regs, \
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(unsigned int)((unsigned long)offset)); \
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} \
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NOKPROBE_SYMBOL(FETCH_FUNC_NAME(stack, type));
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DEFINE_BASIC_FETCH_FUNCS(stack)
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/* No string on the stack entry */
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#define fetch_stack_string NULL
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#define fetch_stack_string_size NULL
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#define DEFINE_FETCH_memory(type) \
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static void FETCH_FUNC_NAME(memory, type)(struct pt_regs *regs, \
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void *addr, void *dest) \
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{ \
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type retval; \
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if (probe_kernel_address(addr, retval)) \
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*(type *)dest = 0; \
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else \
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*(type *)dest = retval; \
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} \
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NOKPROBE_SYMBOL(FETCH_FUNC_NAME(memory, type));
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DEFINE_BASIC_FETCH_FUNCS(memory)
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/*
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* Fetch a null-terminated string. Caller MUST set *(u32 *)dest with max
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* length and relative data location.
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*/
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static void FETCH_FUNC_NAME(memory, string)(struct pt_regs *regs,
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void *addr, void *dest)
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{
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int maxlen = get_rloc_len(*(u32 *)dest);
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u8 *dst = get_rloc_data(dest);
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long ret;
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if (!maxlen)
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return;
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/*
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* Try to get string again, since the string can be changed while
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* probing.
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*/
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ret = strncpy_from_unsafe(dst, addr, maxlen);
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if (ret < 0) { /* Failed to fetch string */
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dst[0] = '\0';
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*(u32 *)dest = make_data_rloc(0, get_rloc_offs(*(u32 *)dest));
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} else {
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*(u32 *)dest = make_data_rloc(ret, get_rloc_offs(*(u32 *)dest));
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}
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}
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NOKPROBE_SYMBOL(FETCH_FUNC_NAME(memory, string));
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/* Return the length of string -- including null terminal byte */
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static void FETCH_FUNC_NAME(memory, string_size)(struct pt_regs *regs,
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void *addr, void *dest)
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{
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mm_segment_t old_fs;
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int ret, len = 0;
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u8 c;
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old_fs = get_fs();
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set_fs(KERNEL_DS);
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pagefault_disable();
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do {
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ret = __copy_from_user_inatomic(&c, (u8 *)addr + len, 1);
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len++;
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} while (c && ret == 0 && len < MAX_STRING_SIZE);
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pagefault_enable();
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set_fs(old_fs);
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if (ret < 0) /* Failed to check the length */
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*(u32 *)dest = 0;
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else
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*(u32 *)dest = len;
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}
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NOKPROBE_SYMBOL(FETCH_FUNC_NAME(memory, string_size));
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#define DEFINE_FETCH_symbol(type) \
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void FETCH_FUNC_NAME(symbol, type)(struct pt_regs *regs, void *data, void *dest)\
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{ \
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struct symbol_cache *sc = data; \
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if (sc->addr) \
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fetch_memory_##type(regs, (void *)sc->addr, dest); \
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else \
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*(type *)dest = 0; \
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} \
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NOKPROBE_SYMBOL(FETCH_FUNC_NAME(symbol, type));
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DEFINE_BASIC_FETCH_FUNCS(symbol)
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DEFINE_FETCH_symbol(string)
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DEFINE_FETCH_symbol(string_size)
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/* kprobes don't support file_offset fetch methods */
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#define fetch_file_offset_u8 NULL
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#define fetch_file_offset_u16 NULL
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#define fetch_file_offset_u32 NULL
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#define fetch_file_offset_u64 NULL
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#define fetch_file_offset_string NULL
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#define fetch_file_offset_string_size NULL
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/* Fetch type information table */
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static const struct fetch_type kprobes_fetch_type_table[] = {
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/* Special types */
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[FETCH_TYPE_STRING] = __ASSIGN_FETCH_TYPE("string", string, string,
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sizeof(u32), 1, "__data_loc char[]"),
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[FETCH_TYPE_STRSIZE] = __ASSIGN_FETCH_TYPE("string_size", u32,
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string_size, sizeof(u32), 0, "u32"),
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/* Basic types */
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ASSIGN_FETCH_TYPE(u8, u8, 0),
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ASSIGN_FETCH_TYPE(u16, u16, 0),
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ASSIGN_FETCH_TYPE(u32, u32, 0),
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ASSIGN_FETCH_TYPE(u64, u64, 0),
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ASSIGN_FETCH_TYPE(s8, u8, 1),
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ASSIGN_FETCH_TYPE(s16, u16, 1),
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ASSIGN_FETCH_TYPE(s32, u32, 1),
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ASSIGN_FETCH_TYPE(s64, u64, 1),
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ASSIGN_FETCH_TYPE_ALIAS(x8, u8, u8, 0),
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ASSIGN_FETCH_TYPE_ALIAS(x16, u16, u16, 0),
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ASSIGN_FETCH_TYPE_ALIAS(x32, u32, u32, 0),
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ASSIGN_FETCH_TYPE_ALIAS(x64, u64, u64, 0),
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ASSIGN_FETCH_TYPE_END
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};
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/*
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* Allocate new trace_probe and initialize it (including kprobes).
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*/
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static struct trace_kprobe *alloc_trace_kprobe(const char *group,
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const char *event,
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void *addr,
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const char *symbol,
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unsigned long offs,
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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_kprobe *tk;
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int ret = -ENOMEM;
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tk = kzalloc(SIZEOF_TRACE_KPROBE(nargs), GFP_KERNEL);
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if (!tk)
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return ERR_PTR(ret);
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tk->nhit = alloc_percpu(unsigned long);
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if (!tk->nhit)
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goto error;
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if (symbol) {
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tk->symbol = kstrdup(symbol, GFP_KERNEL);
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if (!tk->symbol)
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goto error;
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tk->rp.kp.symbol_name = tk->symbol;
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tk->rp.kp.offset = offs;
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} else
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tk->rp.kp.addr = addr;
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if (is_return)
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tk->rp.handler = kretprobe_dispatcher;
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else
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tk->rp.kp.pre_handler = kprobe_dispatcher;
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tk->rp.maxactive = maxactive;
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if (!event || !is_good_name(event)) {
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ret = -EINVAL;
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goto error;
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}
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tk->tp.call.class = &tk->tp.class;
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tk->tp.call.name = kstrdup(event, GFP_KERNEL);
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if (!tk->tp.call.name)
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goto error;
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if (!group || !is_good_name(group)) {
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ret = -EINVAL;
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goto error;
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}
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tk->tp.class.system = kstrdup(group, GFP_KERNEL);
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if (!tk->tp.class.system)
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goto error;
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INIT_LIST_HEAD(&tk->list);
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INIT_LIST_HEAD(&tk->tp.files);
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return tk;
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error:
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kfree(tk->tp.call.name);
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kfree(tk->symbol);
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free_percpu(tk->nhit);
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kfree(tk);
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return ERR_PTR(ret);
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}
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static void free_trace_kprobe(struct trace_kprobe *tk)
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{
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|
int i;
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for (i = 0; i < tk->tp.nr_args; i++)
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traceprobe_free_probe_arg(&tk->tp.args[i]);
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kfree(tk->tp.call.class->system);
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kfree(tk->tp.call.name);
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kfree(tk->symbol);
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free_percpu(tk->nhit);
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kfree(tk);
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}
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static struct trace_kprobe *find_trace_kprobe(const char *event,
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const char *group)
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{
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struct trace_kprobe *tk;
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list_for_each_entry(tk, &probe_list, list)
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if (strcmp(trace_event_name(&tk->tp.call), event) == 0 &&
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strcmp(tk->tp.call.class->system, group) == 0)
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return tk;
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return NULL;
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}
|
|
|
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static inline int __enable_trace_kprobe(struct trace_kprobe *tk)
|
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{
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int ret = 0;
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if (trace_probe_is_registered(&tk->tp) && !trace_kprobe_has_gone(tk)) {
|
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if (trace_kprobe_is_return(tk))
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ret = enable_kretprobe(&tk->rp);
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else
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ret = enable_kprobe(&tk->rp.kp);
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}
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|
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return ret;
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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
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enable_trace_kprobe(struct trace_kprobe *tk, struct trace_event_file *file)
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{
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struct event_file_link *link;
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int ret = 0;
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|
|
|
if (file) {
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|
link = kmalloc(sizeof(*link), GFP_KERNEL);
|
|
if (!link) {
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ret = -ENOMEM;
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goto out;
|
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}
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link->file = file;
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list_add_tail_rcu(&link->list, &tk->tp.files);
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|
|
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tk->tp.flags |= TP_FLAG_TRACE;
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ret = __enable_trace_kprobe(tk);
|
|
if (ret) {
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list_del_rcu(&link->list);
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kfree(link);
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tk->tp.flags &= ~TP_FLAG_TRACE;
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}
|
|
|
|
} else {
|
|
tk->tp.flags |= TP_FLAG_PROFILE;
|
|
ret = __enable_trace_kprobe(tk);
|
|
if (ret)
|
|
tk->tp.flags &= ~TP_FLAG_PROFILE;
|
|
}
|
|
out:
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* Disable trace_probe
|
|
* if the file is NULL, disable "perf" handler, or disable "trace" handler.
|
|
*/
|
|
static int
|
|
disable_trace_kprobe(struct trace_kprobe *tk, struct trace_event_file *file)
|
|
{
|
|
struct event_file_link *link = NULL;
|
|
int wait = 0;
|
|
int ret = 0;
|
|
|
|
if (file) {
|
|
link = find_event_file_link(&tk->tp, file);
|
|
if (!link) {
|
|
ret = -EINVAL;
|
|
goto out;
|
|
}
|
|
|
|
list_del_rcu(&link->list);
|
|
wait = 1;
|
|
if (!list_empty(&tk->tp.files))
|
|
goto out;
|
|
|
|
tk->tp.flags &= ~TP_FLAG_TRACE;
|
|
} else
|
|
tk->tp.flags &= ~TP_FLAG_PROFILE;
|
|
|
|
if (!trace_probe_is_enabled(&tk->tp) && trace_probe_is_registered(&tk->tp)) {
|
|
if (trace_kprobe_is_return(tk))
|
|
disable_kretprobe(&tk->rp);
|
|
else
|
|
disable_kprobe(&tk->rp.kp);
|
|
wait = 1;
|
|
}
|
|
|
|
/*
|
|
* if tk is not added to any list, it must be a local trace_kprobe
|
|
* created with perf_event_open. We don't need to wait for these
|
|
* trace_kprobes
|
|
*/
|
|
if (list_empty(&tk->list))
|
|
wait = 0;
|
|
out:
|
|
if (wait) {
|
|
/*
|
|
* Synchronize with kprobe_trace_func/kretprobe_trace_func
|
|
* to ensure disabled (all running handlers are finished).
|
|
* This is not only for kfree(), but also the caller,
|
|
* trace_remove_event_call() supposes it for releasing
|
|
* event_call related objects, which will be accessed in
|
|
* the kprobe_trace_func/kretprobe_trace_func.
|
|
*/
|
|
synchronize_sched();
|
|
kfree(link); /* Ignored if link == NULL */
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
#if defined(CONFIG_KPROBES_ON_FTRACE) && \
|
|
!defined(CONFIG_KPROBE_EVENTS_ON_NOTRACE)
|
|
static bool within_notrace_func(struct trace_kprobe *tk)
|
|
{
|
|
unsigned long offset, size, addr;
|
|
|
|
addr = trace_kprobe_address(tk);
|
|
if (!addr || !kallsyms_lookup_size_offset(addr, &size, &offset))
|
|
return false;
|
|
|
|
/* Get the entry address of the target function */
|
|
addr -= offset;
|
|
|
|
/*
|
|
* Since ftrace_location_range() does inclusive range check, we need
|
|
* to subtract 1 byte from the end address.
|
|
*/
|
|
return !ftrace_location_range(addr, addr + size - 1);
|
|
}
|
|
#else
|
|
#define within_notrace_func(tk) (false)
|
|
#endif
|
|
|
|
/* Internal register function - just handle k*probes and flags */
|
|
static int __register_trace_kprobe(struct trace_kprobe *tk)
|
|
{
|
|
int i, ret;
|
|
|
|
if (trace_probe_is_registered(&tk->tp))
|
|
return -EINVAL;
|
|
|
|
if (within_notrace_func(tk)) {
|
|
pr_warn("Could not probe notrace function %s\n",
|
|
trace_kprobe_symbol(tk));
|
|
return -EINVAL;
|
|
}
|
|
|
|
for (i = 0; i < tk->tp.nr_args; i++)
|
|
traceprobe_update_arg(&tk->tp.args[i]);
|
|
|
|
/* Set/clear disabled flag according to tp->flag */
|
|
if (trace_probe_is_enabled(&tk->tp))
|
|
tk->rp.kp.flags &= ~KPROBE_FLAG_DISABLED;
|
|
else
|
|
tk->rp.kp.flags |= KPROBE_FLAG_DISABLED;
|
|
|
|
if (trace_kprobe_is_return(tk))
|
|
ret = register_kretprobe(&tk->rp);
|
|
else
|
|
ret = register_kprobe(&tk->rp.kp);
|
|
|
|
if (ret == 0)
|
|
tk->tp.flags |= TP_FLAG_REGISTERED;
|
|
else {
|
|
if (ret == -ENOENT && trace_kprobe_is_on_module(tk)) {
|
|
pr_warn("This probe might be able to register after target module is loaded. Continue.\n");
|
|
ret = 0;
|
|
} else if (ret == -EILSEQ) {
|
|
pr_warn("Probing address(0x%p) is not an instruction boundary.\n",
|
|
tk->rp.kp.addr);
|
|
ret = -EINVAL;
|
|
}
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
/* Internal unregister function - just handle k*probes and flags */
|
|
static void __unregister_trace_kprobe(struct trace_kprobe *tk)
|
|
{
|
|
if (trace_probe_is_registered(&tk->tp)) {
|
|
if (trace_kprobe_is_return(tk))
|
|
unregister_kretprobe(&tk->rp);
|
|
else
|
|
unregister_kprobe(&tk->rp.kp);
|
|
tk->tp.flags &= ~TP_FLAG_REGISTERED;
|
|
/* Cleanup kprobe for reuse */
|
|
if (tk->rp.kp.symbol_name)
|
|
tk->rp.kp.addr = NULL;
|
|
}
|
|
}
|
|
|
|
/* Unregister a trace_probe and probe_event: call with locking probe_lock */
|
|
static int unregister_trace_kprobe(struct trace_kprobe *tk)
|
|
{
|
|
/* Enabled event can not be unregistered */
|
|
if (trace_probe_is_enabled(&tk->tp))
|
|
return -EBUSY;
|
|
|
|
/* Will fail if probe is being used by ftrace or perf */
|
|
if (unregister_kprobe_event(tk))
|
|
return -EBUSY;
|
|
|
|
__unregister_trace_kprobe(tk);
|
|
list_del(&tk->list);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/* Register a trace_probe and probe_event */
|
|
static int register_trace_kprobe(struct trace_kprobe *tk)
|
|
{
|
|
struct trace_kprobe *old_tk;
|
|
int ret;
|
|
|
|
mutex_lock(&probe_lock);
|
|
|
|
/* Delete old (same name) event if exist */
|
|
old_tk = find_trace_kprobe(trace_event_name(&tk->tp.call),
|
|
tk->tp.call.class->system);
|
|
if (old_tk) {
|
|
ret = unregister_trace_kprobe(old_tk);
|
|
if (ret < 0)
|
|
goto end;
|
|
free_trace_kprobe(old_tk);
|
|
}
|
|
|
|
/* Register new event */
|
|
ret = register_kprobe_event(tk);
|
|
if (ret) {
|
|
pr_warn("Failed to register probe event(%d)\n", ret);
|
|
goto end;
|
|
}
|
|
|
|
/* Register k*probe */
|
|
ret = __register_trace_kprobe(tk);
|
|
if (ret < 0)
|
|
unregister_kprobe_event(tk);
|
|
else
|
|
list_add_tail(&tk->list, &probe_list);
|
|
|
|
end:
|
|
mutex_unlock(&probe_lock);
|
|
return ret;
|
|
}
|
|
|
|
/* Module notifier call back, checking event on the module */
|
|
static int trace_kprobe_module_callback(struct notifier_block *nb,
|
|
unsigned long val, void *data)
|
|
{
|
|
struct module *mod = data;
|
|
struct trace_kprobe *tk;
|
|
int ret;
|
|
|
|
if (val != MODULE_STATE_COMING)
|
|
return NOTIFY_DONE;
|
|
|
|
/* Update probes on coming module */
|
|
mutex_lock(&probe_lock);
|
|
list_for_each_entry(tk, &probe_list, list) {
|
|
if (trace_kprobe_within_module(tk, mod)) {
|
|
/* Don't need to check busy - this should have gone. */
|
|
__unregister_trace_kprobe(tk);
|
|
ret = __register_trace_kprobe(tk);
|
|
if (ret)
|
|
pr_warn("Failed to re-register probe %s on %s: %d\n",
|
|
trace_event_name(&tk->tp.call),
|
|
mod->name, ret);
|
|
}
|
|
}
|
|
mutex_unlock(&probe_lock);
|
|
|
|
return NOTIFY_DONE;
|
|
}
|
|
|
|
static struct notifier_block trace_kprobe_module_nb = {
|
|
.notifier_call = trace_kprobe_module_callback,
|
|
.priority = 1 /* Invoked after kprobe module callback */
|
|
};
|
|
|
|
/* Convert certain expected symbols into '_' when generating event names */
|
|
static inline void sanitize_event_name(char *name)
|
|
{
|
|
while (*name++ != '\0')
|
|
if (*name == ':' || *name == '.')
|
|
*name = '_';
|
|
}
|
|
|
|
static int create_trace_kprobe(int argc, char **argv)
|
|
{
|
|
/*
|
|
* Argument syntax:
|
|
* - Add kprobe:
|
|
* p[:[GRP/]EVENT] [MOD:]KSYM[+OFFS]|KADDR [FETCHARGS]
|
|
* - Add kretprobe:
|
|
* r[MAXACTIVE][:[GRP/]EVENT] [MOD:]KSYM[+0] [FETCHARGS]
|
|
* Fetch args:
|
|
* $retval : fetch return value
|
|
* $stack : fetch stack address
|
|
* $stackN : fetch Nth of stack (N:0-)
|
|
* $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)
|
|
* %REG : fetch register REG
|
|
* 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_kprobe *tk;
|
|
int i, ret = 0;
|
|
bool is_return = false, is_delete = false;
|
|
char *symbol = NULL, *event = NULL, *group = NULL;
|
|
int maxactive = 0;
|
|
char *arg;
|
|
long offset = 0;
|
|
void *addr = NULL;
|
|
char buf[MAX_EVENT_NAME_LEN];
|
|
|
|
/* argc must be >= 1 */
|
|
if (argv[0][0] == 'p')
|
|
is_return = false;
|
|
else if (argv[0][0] == 'r')
|
|
is_return = true;
|
|
else if (argv[0][0] == '-')
|
|
is_delete = true;
|
|
else {
|
|
pr_info("Probe definition must be started with 'p', 'r' or"
|
|
" '-'.\n");
|
|
return -EINVAL;
|
|
}
|
|
|
|
event = strchr(&argv[0][1], ':');
|
|
if (event) {
|
|
event[0] = '\0';
|
|
event++;
|
|
}
|
|
if (is_return && isdigit(argv[0][1])) {
|
|
ret = kstrtouint(&argv[0][1], 0, &maxactive);
|
|
if (ret) {
|
|
pr_info("Failed to parse maxactive.\n");
|
|
return ret;
|
|
}
|
|
/* kretprobes instances are iterated over via a list. The
|
|
* maximum should stay reasonable.
|
|
*/
|
|
if (maxactive > KRETPROBE_MAXACTIVE_MAX) {
|
|
pr_info("Maxactive is too big (%d > %d).\n",
|
|
maxactive, KRETPROBE_MAXACTIVE_MAX);
|
|
return -E2BIG;
|
|
}
|
|
}
|
|
|
|
if (event) {
|
|
if (strchr(event, '/')) {
|
|
group = event;
|
|
event = strchr(group, '/') + 1;
|
|
event[-1] = '\0';
|
|
if (strlen(group) == 0) {
|
|
pr_info("Group name is not specified\n");
|
|
return -EINVAL;
|
|
}
|
|
}
|
|
if (strlen(event) == 0) {
|
|
pr_info("Event name is not specified\n");
|
|
return -EINVAL;
|
|
}
|
|
}
|
|
if (!group)
|
|
group = KPROBE_EVENT_SYSTEM;
|
|
|
|
if (is_delete) {
|
|
if (!event) {
|
|
pr_info("Delete command needs an event name.\n");
|
|
return -EINVAL;
|
|
}
|
|
mutex_lock(&probe_lock);
|
|
tk = find_trace_kprobe(event, group);
|
|
if (!tk) {
|
|
mutex_unlock(&probe_lock);
|
|
pr_info("Event %s/%s doesn't exist.\n", group, event);
|
|
return -ENOENT;
|
|
}
|
|
/* delete an event */
|
|
ret = unregister_trace_kprobe(tk);
|
|
if (ret == 0)
|
|
free_trace_kprobe(tk);
|
|
mutex_unlock(&probe_lock);
|
|
return ret;
|
|
}
|
|
|
|
if (argc < 2) {
|
|
pr_info("Probe point is not specified.\n");
|
|
return -EINVAL;
|
|
}
|
|
|
|
/* try to parse an address. if that fails, try to read the
|
|
* input as a symbol. */
|
|
if (kstrtoul(argv[1], 0, (unsigned long *)&addr)) {
|
|
/* a symbol specified */
|
|
symbol = argv[1];
|
|
/* TODO: support .init module functions */
|
|
ret = traceprobe_split_symbol_offset(symbol, &offset);
|
|
if (ret || offset < 0 || offset > UINT_MAX) {
|
|
pr_info("Failed to parse either an address or a symbol.\n");
|
|
return ret;
|
|
}
|
|
if (offset && is_return &&
|
|
!kprobe_on_func_entry(NULL, symbol, offset)) {
|
|
pr_info("Given offset is not valid for return probe.\n");
|
|
return -EINVAL;
|
|
}
|
|
}
|
|
argc -= 2; argv += 2;
|
|
|
|
/* setup a probe */
|
|
if (!event) {
|
|
/* Make a new event name */
|
|
if (symbol)
|
|
snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_%ld",
|
|
is_return ? 'r' : 'p', symbol, offset);
|
|
else
|
|
snprintf(buf, MAX_EVENT_NAME_LEN, "%c_0x%p",
|
|
is_return ? 'r' : 'p', addr);
|
|
sanitize_event_name(buf);
|
|
event = buf;
|
|
}
|
|
tk = alloc_trace_kprobe(group, event, addr, symbol, offset, maxactive,
|
|
argc, is_return);
|
|
if (IS_ERR(tk)) {
|
|
pr_info("Failed to allocate trace_probe.(%d)\n",
|
|
(int)PTR_ERR(tk));
|
|
return PTR_ERR(tk);
|
|
}
|
|
|
|
/* parse arguments */
|
|
ret = 0;
|
|
for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
|
|
struct probe_arg *parg = &tk->tp.args[i];
|
|
|
|
/* Increment count for freeing args in error case */
|
|
tk->tp.nr_args++;
|
|
|
|
/* Parse argument name */
|
|
arg = strchr(argv[i], '=');
|
|
if (arg) {
|
|
*arg++ = '\0';
|
|
parg->name = kstrdup(argv[i], GFP_KERNEL);
|
|
} else {
|
|
arg = argv[i];
|
|
/* If argument name is omitted, set "argN" */
|
|
snprintf(buf, MAX_EVENT_NAME_LEN, "arg%d", i + 1);
|
|
parg->name = kstrdup(buf, GFP_KERNEL);
|
|
}
|
|
|
|
if (!parg->name) {
|
|
pr_info("Failed to allocate argument[%d] name.\n", i);
|
|
ret = -ENOMEM;
|
|
goto error;
|
|
}
|
|
|
|
if (!is_good_name(parg->name)) {
|
|
pr_info("Invalid argument[%d] name: %s\n",
|
|
i, parg->name);
|
|
ret = -EINVAL;
|
|
goto error;
|
|
}
|
|
|
|
if (traceprobe_conflict_field_name(parg->name,
|
|
tk->tp.args, i)) {
|
|
pr_info("Argument[%d] name '%s' conflicts with "
|
|
"another field.\n", i, argv[i]);
|
|
ret = -EINVAL;
|
|
goto error;
|
|
}
|
|
|
|
/* Parse fetch argument */
|
|
ret = traceprobe_parse_probe_arg(arg, &tk->tp.size, parg,
|
|
is_return, true,
|
|
kprobes_fetch_type_table);
|
|
if (ret) {
|
|
pr_info("Parse error at argument[%d]. (%d)\n", i, ret);
|
|
goto error;
|
|
}
|
|
}
|
|
|
|
ret = register_trace_kprobe(tk);
|
|
if (ret)
|
|
goto error;
|
|
return 0;
|
|
|
|
error:
|
|
free_trace_kprobe(tk);
|
|
return ret;
|
|
}
|
|
|
|
static int release_all_trace_kprobes(void)
|
|
{
|
|
struct trace_kprobe *tk;
|
|
int ret = 0;
|
|
|
|
mutex_lock(&probe_lock);
|
|
/* Ensure no probe is in use. */
|
|
list_for_each_entry(tk, &probe_list, list)
|
|
if (trace_probe_is_enabled(&tk->tp)) {
|
|
ret = -EBUSY;
|
|
goto end;
|
|
}
|
|
/* TODO: Use batch unregistration */
|
|
while (!list_empty(&probe_list)) {
|
|
tk = list_entry(probe_list.next, struct trace_kprobe, list);
|
|
ret = unregister_trace_kprobe(tk);
|
|
if (ret)
|
|
goto end;
|
|
free_trace_kprobe(tk);
|
|
}
|
|
|
|
end:
|
|
mutex_unlock(&probe_lock);
|
|
|
|
return ret;
|
|
}
|
|
|
|
/* Probes listing interfaces */
|
|
static void *probes_seq_start(struct seq_file *m, loff_t *pos)
|
|
{
|
|
mutex_lock(&probe_lock);
|
|
return seq_list_start(&probe_list, *pos);
|
|
}
|
|
|
|
static void *probes_seq_next(struct seq_file *m, void *v, loff_t *pos)
|
|
{
|
|
return seq_list_next(v, &probe_list, pos);
|
|
}
|
|
|
|
static void probes_seq_stop(struct seq_file *m, void *v)
|
|
{
|
|
mutex_unlock(&probe_lock);
|
|
}
|
|
|
|
static int probes_seq_show(struct seq_file *m, void *v)
|
|
{
|
|
struct trace_kprobe *tk = v;
|
|
int i;
|
|
|
|
seq_putc(m, trace_kprobe_is_return(tk) ? 'r' : 'p');
|
|
seq_printf(m, ":%s/%s", tk->tp.call.class->system,
|
|
trace_event_name(&tk->tp.call));
|
|
|
|
if (!tk->symbol)
|
|
seq_printf(m, " 0x%p", tk->rp.kp.addr);
|
|
else if (tk->rp.kp.offset)
|
|
seq_printf(m, " %s+%u", trace_kprobe_symbol(tk),
|
|
tk->rp.kp.offset);
|
|
else
|
|
seq_printf(m, " %s", trace_kprobe_symbol(tk));
|
|
|
|
for (i = 0; i < tk->tp.nr_args; i++)
|
|
seq_printf(m, " %s=%s", tk->tp.args[i].name, tk->tp.args[i].comm);
|
|
seq_putc(m, '\n');
|
|
|
|
return 0;
|
|
}
|
|
|
|
static const struct seq_operations probes_seq_op = {
|
|
.start = probes_seq_start,
|
|
.next = probes_seq_next,
|
|
.stop = probes_seq_stop,
|
|
.show = probes_seq_show
|
|
};
|
|
|
|
static int probes_open(struct inode *inode, struct file *file)
|
|
{
|
|
int ret;
|
|
|
|
if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
|
|
ret = release_all_trace_kprobes();
|
|
if (ret < 0)
|
|
return ret;
|
|
}
|
|
|
|
return seq_open(file, &probes_seq_op);
|
|
}
|
|
|
|
static ssize_t probes_write(struct file *file, const char __user *buffer,
|
|
size_t count, loff_t *ppos)
|
|
{
|
|
return trace_parse_run_command(file, buffer, count, ppos,
|
|
create_trace_kprobe);
|
|
}
|
|
|
|
static const struct file_operations kprobe_events_ops = {
|
|
.owner = THIS_MODULE,
|
|
.open = probes_open,
|
|
.read = seq_read,
|
|
.llseek = seq_lseek,
|
|
.release = seq_release,
|
|
.write = probes_write,
|
|
};
|
|
|
|
/* Probes profiling interfaces */
|
|
static int probes_profile_seq_show(struct seq_file *m, void *v)
|
|
{
|
|
struct trace_kprobe *tk = v;
|
|
|
|
seq_printf(m, " %-44s %15lu %15lu\n",
|
|
trace_event_name(&tk->tp.call),
|
|
trace_kprobe_nhit(tk),
|
|
tk->rp.kp.nmissed);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static const struct seq_operations profile_seq_op = {
|
|
.start = probes_seq_start,
|
|
.next = probes_seq_next,
|
|
.stop = probes_seq_stop,
|
|
.show = probes_profile_seq_show
|
|
};
|
|
|
|
static int profile_open(struct inode *inode, struct file *file)
|
|
{
|
|
return seq_open(file, &profile_seq_op);
|
|
}
|
|
|
|
static const struct file_operations kprobe_profile_ops = {
|
|
.owner = THIS_MODULE,
|
|
.open = profile_open,
|
|
.read = seq_read,
|
|
.llseek = seq_lseek,
|
|
.release = seq_release,
|
|
};
|
|
|
|
/* Kprobe handler */
|
|
static nokprobe_inline void
|
|
__kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs,
|
|
struct trace_event_file *trace_file)
|
|
{
|
|
struct kprobe_trace_entry_head *entry;
|
|
struct ring_buffer_event *event;
|
|
struct ring_buffer *buffer;
|
|
int size, dsize, pc;
|
|
unsigned long irq_flags;
|
|
struct trace_event_call *call = &tk->tp.call;
|
|
|
|
WARN_ON(call != trace_file->event_call);
|
|
|
|
if (trace_trigger_soft_disabled(trace_file))
|
|
return;
|
|
|
|
local_save_flags(irq_flags);
|
|
pc = preempt_count();
|
|
|
|
dsize = __get_data_size(&tk->tp, regs);
|
|
size = sizeof(*entry) + tk->tp.size + dsize;
|
|
|
|
event = trace_event_buffer_lock_reserve(&buffer, trace_file,
|
|
call->event.type,
|
|
size, irq_flags, pc);
|
|
if (!event)
|
|
return;
|
|
|
|
entry = ring_buffer_event_data(event);
|
|
entry->ip = (unsigned long)tk->rp.kp.addr;
|
|
store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
|
|
|
|
event_trigger_unlock_commit_regs(trace_file, buffer, event,
|
|
entry, irq_flags, pc, regs);
|
|
}
|
|
|
|
static void
|
|
kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs)
|
|
{
|
|
struct event_file_link *link;
|
|
|
|
list_for_each_entry_rcu(link, &tk->tp.files, list)
|
|
__kprobe_trace_func(tk, regs, link->file);
|
|
}
|
|
NOKPROBE_SYMBOL(kprobe_trace_func);
|
|
|
|
/* Kretprobe handler */
|
|
static nokprobe_inline void
|
|
__kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
|
|
struct pt_regs *regs,
|
|
struct trace_event_file *trace_file)
|
|
{
|
|
struct kretprobe_trace_entry_head *entry;
|
|
struct ring_buffer_event *event;
|
|
struct ring_buffer *buffer;
|
|
int size, pc, dsize;
|
|
unsigned long irq_flags;
|
|
struct trace_event_call *call = &tk->tp.call;
|
|
|
|
WARN_ON(call != trace_file->event_call);
|
|
|
|
if (trace_trigger_soft_disabled(trace_file))
|
|
return;
|
|
|
|
local_save_flags(irq_flags);
|
|
pc = preempt_count();
|
|
|
|
dsize = __get_data_size(&tk->tp, regs);
|
|
size = sizeof(*entry) + tk->tp.size + dsize;
|
|
|
|
event = trace_event_buffer_lock_reserve(&buffer, trace_file,
|
|
call->event.type,
|
|
size, irq_flags, pc);
|
|
if (!event)
|
|
return;
|
|
|
|
entry = ring_buffer_event_data(event);
|
|
entry->func = (unsigned long)tk->rp.kp.addr;
|
|
entry->ret_ip = (unsigned long)ri->ret_addr;
|
|
store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
|
|
|
|
event_trigger_unlock_commit_regs(trace_file, buffer, event,
|
|
entry, irq_flags, pc, regs);
|
|
}
|
|
|
|
static void
|
|
kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
|
|
struct pt_regs *regs)
|
|
{
|
|
struct event_file_link *link;
|
|
|
|
list_for_each_entry_rcu(link, &tk->tp.files, list)
|
|
__kretprobe_trace_func(tk, ri, regs, link->file);
|
|
}
|
|
NOKPROBE_SYMBOL(kretprobe_trace_func);
|
|
|
|
/* Event entry printers */
|
|
static enum print_line_t
|
|
print_kprobe_event(struct trace_iterator *iter, int flags,
|
|
struct trace_event *event)
|
|
{
|
|
struct kprobe_trace_entry_head *field;
|
|
struct trace_seq *s = &iter->seq;
|
|
struct trace_probe *tp;
|
|
u8 *data;
|
|
int i;
|
|
|
|
field = (struct kprobe_trace_entry_head *)iter->ent;
|
|
tp = container_of(event, struct trace_probe, call.event);
|
|
|
|
trace_seq_printf(s, "%s: (", trace_event_name(&tp->call));
|
|
|
|
if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET))
|
|
goto out;
|
|
|
|
trace_seq_putc(s, ')');
|
|
|
|
data = (u8 *)&field[1];
|
|
for (i = 0; i < tp->nr_args; i++)
|
|
if (!tp->args[i].type->print(s, tp->args[i].name,
|
|
data + tp->args[i].offset, field))
|
|
goto out;
|
|
|
|
trace_seq_putc(s, '\n');
|
|
out:
|
|
return trace_handle_return(s);
|
|
}
|
|
|
|
static enum print_line_t
|
|
print_kretprobe_event(struct trace_iterator *iter, int flags,
|
|
struct trace_event *event)
|
|
{
|
|
struct kretprobe_trace_entry_head *field;
|
|
struct trace_seq *s = &iter->seq;
|
|
struct trace_probe *tp;
|
|
u8 *data;
|
|
int i;
|
|
|
|
field = (struct kretprobe_trace_entry_head *)iter->ent;
|
|
tp = container_of(event, struct trace_probe, call.event);
|
|
|
|
trace_seq_printf(s, "%s: (", trace_event_name(&tp->call));
|
|
|
|
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, ')');
|
|
|
|
data = (u8 *)&field[1];
|
|
for (i = 0; i < tp->nr_args; i++)
|
|
if (!tp->args[i].type->print(s, tp->args[i].name,
|
|
data + tp->args[i].offset, field))
|
|
goto out;
|
|
|
|
trace_seq_putc(s, '\n');
|
|
|
|
out:
|
|
return trace_handle_return(s);
|
|
}
|
|
|
|
|
|
static int kprobe_event_define_fields(struct trace_event_call *event_call)
|
|
{
|
|
int ret, i;
|
|
struct kprobe_trace_entry_head field;
|
|
struct trace_kprobe *tk = (struct trace_kprobe *)event_call->data;
|
|
|
|
DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0);
|
|
/* Set argument names as fields */
|
|
for (i = 0; i < tk->tp.nr_args; i++) {
|
|
struct probe_arg *parg = &tk->tp.args[i];
|
|
|
|
ret = trace_define_field(event_call, parg->type->fmttype,
|
|
parg->name,
|
|
sizeof(field) + parg->offset,
|
|
parg->type->size,
|
|
parg->type->is_signed,
|
|
FILTER_OTHER);
|
|
if (ret)
|
|
return ret;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static int kretprobe_event_define_fields(struct trace_event_call *event_call)
|
|
{
|
|
int ret, i;
|
|
struct kretprobe_trace_entry_head field;
|
|
struct trace_kprobe *tk = (struct trace_kprobe *)event_call->data;
|
|
|
|
DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0);
|
|
DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0);
|
|
/* Set argument names as fields */
|
|
for (i = 0; i < tk->tp.nr_args; i++) {
|
|
struct probe_arg *parg = &tk->tp.args[i];
|
|
|
|
ret = trace_define_field(event_call, parg->type->fmttype,
|
|
parg->name,
|
|
sizeof(field) + parg->offset,
|
|
parg->type->size,
|
|
parg->type->is_signed,
|
|
FILTER_OTHER);
|
|
if (ret)
|
|
return ret;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
#ifdef CONFIG_PERF_EVENTS
|
|
|
|
/* Kprobe profile handler */
|
|
static int
|
|
kprobe_perf_func(struct trace_kprobe *tk, struct pt_regs *regs)
|
|
{
|
|
struct trace_event_call *call = &tk->tp.call;
|
|
struct kprobe_trace_entry_head *entry;
|
|
struct hlist_head *head;
|
|
int size, __size, dsize;
|
|
int rctx;
|
|
|
|
if (bpf_prog_array_valid(call)) {
|
|
unsigned long orig_ip = instruction_pointer(regs);
|
|
int ret;
|
|
|
|
ret = trace_call_bpf(call, regs);
|
|
|
|
/*
|
|
* We need to check and see if we modified the pc of the
|
|
* pt_regs, and if so return 1 so that we don't do the
|
|
* single stepping.
|
|
*/
|
|
if (orig_ip != instruction_pointer(regs))
|
|
return 1;
|
|
if (!ret)
|
|
return 0;
|
|
}
|
|
|
|
head = this_cpu_ptr(call->perf_events);
|
|
if (hlist_empty(head))
|
|
return 0;
|
|
|
|
dsize = __get_data_size(&tk->tp, regs);
|
|
__size = sizeof(*entry) + tk->tp.size + dsize;
|
|
size = ALIGN(__size + sizeof(u32), sizeof(u64));
|
|
size -= sizeof(u32);
|
|
|
|
entry = perf_trace_buf_alloc(size, NULL, &rctx);
|
|
if (!entry)
|
|
return 0;
|
|
|
|
entry->ip = (unsigned long)tk->rp.kp.addr;
|
|
memset(&entry[1], 0, dsize);
|
|
store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
|
|
perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
|
|
head, NULL);
|
|
return 0;
|
|
}
|
|
NOKPROBE_SYMBOL(kprobe_perf_func);
|
|
|
|
/* Kretprobe profile handler */
|
|
static void
|
|
kretprobe_perf_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
|
|
struct pt_regs *regs)
|
|
{
|
|
struct trace_event_call *call = &tk->tp.call;
|
|
struct kretprobe_trace_entry_head *entry;
|
|
struct hlist_head *head;
|
|
int size, __size, dsize;
|
|
int rctx;
|
|
|
|
if (bpf_prog_array_valid(call) && !trace_call_bpf(call, regs))
|
|
return;
|
|
|
|
head = this_cpu_ptr(call->perf_events);
|
|
if (hlist_empty(head))
|
|
return;
|
|
|
|
dsize = __get_data_size(&tk->tp, regs);
|
|
__size = sizeof(*entry) + tk->tp.size + dsize;
|
|
size = ALIGN(__size + sizeof(u32), sizeof(u64));
|
|
size -= sizeof(u32);
|
|
|
|
entry = perf_trace_buf_alloc(size, NULL, &rctx);
|
|
if (!entry)
|
|
return;
|
|
|
|
entry->func = (unsigned long)tk->rp.kp.addr;
|
|
entry->ret_ip = (unsigned long)ri->ret_addr;
|
|
store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
|
|
perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
|
|
head, NULL);
|
|
}
|
|
NOKPROBE_SYMBOL(kretprobe_perf_func);
|
|
|
|
int bpf_get_kprobe_info(const struct perf_event *event, u32 *fd_type,
|
|
const char **symbol, u64 *probe_offset,
|
|
u64 *probe_addr, bool perf_type_tracepoint)
|
|
{
|
|
const char *pevent = trace_event_name(event->tp_event);
|
|
const char *group = event->tp_event->class->system;
|
|
struct trace_kprobe *tk;
|
|
|
|
if (perf_type_tracepoint)
|
|
tk = find_trace_kprobe(pevent, group);
|
|
else
|
|
tk = event->tp_event->data;
|
|
if (!tk)
|
|
return -EINVAL;
|
|
|
|
*fd_type = trace_kprobe_is_return(tk) ? BPF_FD_TYPE_KRETPROBE
|
|
: BPF_FD_TYPE_KPROBE;
|
|
if (tk->symbol) {
|
|
*symbol = tk->symbol;
|
|
*probe_offset = tk->rp.kp.offset;
|
|
*probe_addr = 0;
|
|
} else {
|
|
*symbol = NULL;
|
|
*probe_offset = 0;
|
|
*probe_addr = (unsigned long)tk->rp.kp.addr;
|
|
}
|
|
return 0;
|
|
}
|
|
#endif /* CONFIG_PERF_EVENTS */
|
|
|
|
/*
|
|
* called by perf_trace_init() or __ftrace_set_clr_event() under event_mutex.
|
|
*
|
|
* kprobe_trace_self_tests_init() does enable_trace_probe/disable_trace_probe
|
|
* lockless, but we can't race with this __init function.
|
|
*/
|
|
static int kprobe_register(struct trace_event_call *event,
|
|
enum trace_reg type, void *data)
|
|
{
|
|
struct trace_kprobe *tk = (struct trace_kprobe *)event->data;
|
|
struct trace_event_file *file = data;
|
|
|
|
switch (type) {
|
|
case TRACE_REG_REGISTER:
|
|
return enable_trace_kprobe(tk, file);
|
|
case TRACE_REG_UNREGISTER:
|
|
return disable_trace_kprobe(tk, file);
|
|
|
|
#ifdef CONFIG_PERF_EVENTS
|
|
case TRACE_REG_PERF_REGISTER:
|
|
return enable_trace_kprobe(tk, NULL);
|
|
case TRACE_REG_PERF_UNREGISTER:
|
|
return disable_trace_kprobe(tk, 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;
|
|
}
|
|
|
|
static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs)
|
|
{
|
|
struct trace_kprobe *tk = container_of(kp, struct trace_kprobe, rp.kp);
|
|
int ret = 0;
|
|
|
|
raw_cpu_inc(*tk->nhit);
|
|
|
|
if (tk->tp.flags & TP_FLAG_TRACE)
|
|
kprobe_trace_func(tk, regs);
|
|
#ifdef CONFIG_PERF_EVENTS
|
|
if (tk->tp.flags & TP_FLAG_PROFILE)
|
|
ret = kprobe_perf_func(tk, regs);
|
|
#endif
|
|
return ret;
|
|
}
|
|
NOKPROBE_SYMBOL(kprobe_dispatcher);
|
|
|
|
static int
|
|
kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs)
|
|
{
|
|
struct trace_kprobe *tk = container_of(ri->rp, struct trace_kprobe, rp);
|
|
|
|
raw_cpu_inc(*tk->nhit);
|
|
|
|
if (tk->tp.flags & TP_FLAG_TRACE)
|
|
kretprobe_trace_func(tk, ri, regs);
|
|
#ifdef CONFIG_PERF_EVENTS
|
|
if (tk->tp.flags & TP_FLAG_PROFILE)
|
|
kretprobe_perf_func(tk, ri, regs);
|
|
#endif
|
|
return 0; /* We don't tweek kernel, so just return 0 */
|
|
}
|
|
NOKPROBE_SYMBOL(kretprobe_dispatcher);
|
|
|
|
static struct trace_event_functions kretprobe_funcs = {
|
|
.trace = print_kretprobe_event
|
|
};
|
|
|
|
static struct trace_event_functions kprobe_funcs = {
|
|
.trace = print_kprobe_event
|
|
};
|
|
|
|
static inline void init_trace_event_call(struct trace_kprobe *tk,
|
|
struct trace_event_call *call)
|
|
{
|
|
INIT_LIST_HEAD(&call->class->fields);
|
|
if (trace_kprobe_is_return(tk)) {
|
|
call->event.funcs = &kretprobe_funcs;
|
|
call->class->define_fields = kretprobe_event_define_fields;
|
|
} else {
|
|
call->event.funcs = &kprobe_funcs;
|
|
call->class->define_fields = kprobe_event_define_fields;
|
|
}
|
|
|
|
call->flags = TRACE_EVENT_FL_KPROBE;
|
|
call->class->reg = kprobe_register;
|
|
call->data = tk;
|
|
}
|
|
|
|
static int register_kprobe_event(struct trace_kprobe *tk)
|
|
{
|
|
struct trace_event_call *call = &tk->tp.call;
|
|
int ret = 0;
|
|
|
|
init_trace_event_call(tk, call);
|
|
|
|
if (set_print_fmt(&tk->tp, trace_kprobe_is_return(tk)) < 0)
|
|
return -ENOMEM;
|
|
ret = register_trace_event(&call->event);
|
|
if (!ret) {
|
|
kfree(call->print_fmt);
|
|
return -ENODEV;
|
|
}
|
|
ret = trace_add_event_call(call);
|
|
if (ret) {
|
|
pr_info("Failed to register kprobe event: %s\n",
|
|
trace_event_name(call));
|
|
kfree(call->print_fmt);
|
|
unregister_trace_event(&call->event);
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
static int unregister_kprobe_event(struct trace_kprobe *tk)
|
|
{
|
|
int ret;
|
|
|
|
/* tp->event is unregistered in trace_remove_event_call() */
|
|
ret = trace_remove_event_call(&tk->tp.call);
|
|
if (!ret)
|
|
kfree(tk->tp.call.print_fmt);
|
|
return ret;
|
|
}
|
|
|
|
#ifdef CONFIG_PERF_EVENTS
|
|
/* create a trace_kprobe, but don't add it to global lists */
|
|
struct trace_event_call *
|
|
create_local_trace_kprobe(char *func, void *addr, unsigned long offs,
|
|
bool is_return)
|
|
{
|
|
struct trace_kprobe *tk;
|
|
int ret;
|
|
char *event;
|
|
|
|
/*
|
|
* local trace_kprobes are not added to probe_list, so they are never
|
|
* searched in find_trace_kprobe(). Therefore, there is no concern of
|
|
* duplicated name here.
|
|
*/
|
|
event = func ? func : "DUMMY_EVENT";
|
|
|
|
tk = alloc_trace_kprobe(KPROBE_EVENT_SYSTEM, event, (void *)addr, func,
|
|
offs, 0 /* maxactive */, 0 /* nargs */,
|
|
is_return);
|
|
|
|
if (IS_ERR(tk)) {
|
|
pr_info("Failed to allocate trace_probe.(%d)\n",
|
|
(int)PTR_ERR(tk));
|
|
return ERR_CAST(tk);
|
|
}
|
|
|
|
init_trace_event_call(tk, &tk->tp.call);
|
|
|
|
if (set_print_fmt(&tk->tp, trace_kprobe_is_return(tk)) < 0) {
|
|
ret = -ENOMEM;
|
|
goto error;
|
|
}
|
|
|
|
ret = __register_trace_kprobe(tk);
|
|
if (ret < 0) {
|
|
kfree(tk->tp.call.print_fmt);
|
|
goto error;
|
|
}
|
|
|
|
return &tk->tp.call;
|
|
error:
|
|
free_trace_kprobe(tk);
|
|
return ERR_PTR(ret);
|
|
}
|
|
|
|
void destroy_local_trace_kprobe(struct trace_event_call *event_call)
|
|
{
|
|
struct trace_kprobe *tk;
|
|
|
|
tk = container_of(event_call, struct trace_kprobe, tp.call);
|
|
|
|
if (trace_probe_is_enabled(&tk->tp)) {
|
|
WARN_ON(1);
|
|
return;
|
|
}
|
|
|
|
__unregister_trace_kprobe(tk);
|
|
|
|
kfree(tk->tp.call.print_fmt);
|
|
free_trace_kprobe(tk);
|
|
}
|
|
#endif /* CONFIG_PERF_EVENTS */
|
|
|
|
/* Make a tracefs interface for controlling probe points */
|
|
static __init int init_kprobe_trace(void)
|
|
{
|
|
struct dentry *d_tracer;
|
|
struct dentry *entry;
|
|
|
|
if (register_module_notifier(&trace_kprobe_module_nb))
|
|
return -EINVAL;
|
|
|
|
d_tracer = tracing_init_dentry();
|
|
if (IS_ERR(d_tracer))
|
|
return 0;
|
|
|
|
entry = tracefs_create_file("kprobe_events", 0644, d_tracer,
|
|
NULL, &kprobe_events_ops);
|
|
|
|
/* Event list interface */
|
|
if (!entry)
|
|
pr_warn("Could not create tracefs 'kprobe_events' entry\n");
|
|
|
|
/* Profile interface */
|
|
entry = tracefs_create_file("kprobe_profile", 0444, d_tracer,
|
|
NULL, &kprobe_profile_ops);
|
|
|
|
if (!entry)
|
|
pr_warn("Could not create tracefs 'kprobe_profile' entry\n");
|
|
return 0;
|
|
}
|
|
fs_initcall(init_kprobe_trace);
|
|
|
|
|
|
#ifdef CONFIG_FTRACE_STARTUP_TEST
|
|
static __init struct trace_event_file *
|
|
find_trace_probe_file(struct trace_kprobe *tk, struct trace_array *tr)
|
|
{
|
|
struct trace_event_file *file;
|
|
|
|
list_for_each_entry(file, &tr->events, list)
|
|
if (file->event_call == &tk->tp.call)
|
|
return file;
|
|
|
|
return NULL;
|
|
}
|
|
|
|
/*
|
|
* Nobody but us can call enable_trace_kprobe/disable_trace_kprobe at this
|
|
* stage, we can do this lockless.
|
|
*/
|
|
static __init int kprobe_trace_self_tests_init(void)
|
|
{
|
|
int ret, warn = 0;
|
|
int (*target)(int, int, int, int, int, int);
|
|
struct trace_kprobe *tk;
|
|
struct trace_event_file *file;
|
|
|
|
if (tracing_is_disabled())
|
|
return -ENODEV;
|
|
|
|
target = kprobe_trace_selftest_target;
|
|
|
|
pr_info("Testing kprobe tracing: ");
|
|
|
|
ret = trace_run_command("p:testprobe kprobe_trace_selftest_target "
|
|
"$stack $stack0 +0($stack)",
|
|
create_trace_kprobe);
|
|
if (WARN_ON_ONCE(ret)) {
|
|
pr_warn("error on probing function entry.\n");
|
|
warn++;
|
|
} else {
|
|
/* Enable trace point */
|
|
tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
|
|
if (WARN_ON_ONCE(tk == NULL)) {
|
|
pr_warn("error on getting new probe.\n");
|
|
warn++;
|
|
} else {
|
|
file = find_trace_probe_file(tk, top_trace_array());
|
|
if (WARN_ON_ONCE(file == NULL)) {
|
|
pr_warn("error on getting probe file.\n");
|
|
warn++;
|
|
} else
|
|
enable_trace_kprobe(tk, file);
|
|
}
|
|
}
|
|
|
|
ret = trace_run_command("r:testprobe2 kprobe_trace_selftest_target "
|
|
"$retval", create_trace_kprobe);
|
|
if (WARN_ON_ONCE(ret)) {
|
|
pr_warn("error on probing function return.\n");
|
|
warn++;
|
|
} else {
|
|
/* Enable trace point */
|
|
tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
|
|
if (WARN_ON_ONCE(tk == NULL)) {
|
|
pr_warn("error on getting 2nd new probe.\n");
|
|
warn++;
|
|
} else {
|
|
file = find_trace_probe_file(tk, top_trace_array());
|
|
if (WARN_ON_ONCE(file == NULL)) {
|
|
pr_warn("error on getting probe file.\n");
|
|
warn++;
|
|
} else
|
|
enable_trace_kprobe(tk, file);
|
|
}
|
|
}
|
|
|
|
if (warn)
|
|
goto end;
|
|
|
|
ret = target(1, 2, 3, 4, 5, 6);
|
|
|
|
/*
|
|
* Not expecting an error here, the check is only to prevent the
|
|
* optimizer from removing the call to target() as otherwise there
|
|
* are no side-effects and the call is never performed.
|
|
*/
|
|
if (ret != 21)
|
|
warn++;
|
|
|
|
/* Disable trace points before removing it */
|
|
tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
|
|
if (WARN_ON_ONCE(tk == NULL)) {
|
|
pr_warn("error on getting test probe.\n");
|
|
warn++;
|
|
} else {
|
|
if (trace_kprobe_nhit(tk) != 1) {
|
|
pr_warn("incorrect number of testprobe hits\n");
|
|
warn++;
|
|
}
|
|
|
|
file = find_trace_probe_file(tk, top_trace_array());
|
|
if (WARN_ON_ONCE(file == NULL)) {
|
|
pr_warn("error on getting probe file.\n");
|
|
warn++;
|
|
} else
|
|
disable_trace_kprobe(tk, file);
|
|
}
|
|
|
|
tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
|
|
if (WARN_ON_ONCE(tk == NULL)) {
|
|
pr_warn("error on getting 2nd test probe.\n");
|
|
warn++;
|
|
} else {
|
|
if (trace_kprobe_nhit(tk) != 1) {
|
|
pr_warn("incorrect number of testprobe2 hits\n");
|
|
warn++;
|
|
}
|
|
|
|
file = find_trace_probe_file(tk, top_trace_array());
|
|
if (WARN_ON_ONCE(file == NULL)) {
|
|
pr_warn("error on getting probe file.\n");
|
|
warn++;
|
|
} else
|
|
disable_trace_kprobe(tk, file);
|
|
}
|
|
|
|
ret = trace_run_command("-:testprobe", create_trace_kprobe);
|
|
if (WARN_ON_ONCE(ret)) {
|
|
pr_warn("error on deleting a probe.\n");
|
|
warn++;
|
|
}
|
|
|
|
ret = trace_run_command("-:testprobe2", create_trace_kprobe);
|
|
if (WARN_ON_ONCE(ret)) {
|
|
pr_warn("error on deleting a probe.\n");
|
|
warn++;
|
|
}
|
|
|
|
end:
|
|
release_all_trace_kprobes();
|
|
/*
|
|
* Wait for the optimizer work to finish. Otherwise it might fiddle
|
|
* with probes in already freed __init text.
|
|
*/
|
|
wait_for_kprobe_optimizer();
|
|
if (warn)
|
|
pr_cont("NG: Some tests are failed. Please check them.\n");
|
|
else
|
|
pr_cont("OK\n");
|
|
return 0;
|
|
}
|
|
|
|
late_initcall(kprobe_trace_self_tests_init);
|
|
|
|
#endif
|