@@ -66,6 +66,7 @@ int register_fprobe(struct fprobe *fp, const char *filter, const char *notfilter
int register_fprobe_ips(struct fprobe *fp, unsigned long *addrs, int num);
int register_fprobe_syms(struct fprobe *fp, const char **syms, int num);
int unregister_fprobe(struct fprobe *fp);
+bool fprobe_is_registered(struct fprobe *fp);
#else
static inline int register_fprobe(struct fprobe *fp, const char *filter, const char *notfilter)
{
@@ -83,6 +84,10 @@ static inline int unregister_fprobe(struct fprobe *fp)
{
return -EOPNOTSUPP;
}
+static inline bool fprobe_is_registered(struct fprobe *fp)
+{
+ return false;
+}
#endif
/**
@@ -318,6 +318,7 @@ enum {
TRACE_EVENT_FL_KPROBE_BIT,
TRACE_EVENT_FL_UPROBE_BIT,
TRACE_EVENT_FL_EPROBE_BIT,
+ TRACE_EVENT_FL_FPROBE_BIT,
TRACE_EVENT_FL_CUSTOM_BIT,
};
@@ -332,6 +333,7 @@ enum {
* KPROBE - Event is a kprobe
* UPROBE - Event is a uprobe
* EPROBE - Event is an event probe
+ * FPROBE - Event is an function probe
* CUSTOM - Event is a custom event (to be attached to an exsiting tracepoint)
* This is set when the custom event has not been attached
* to a tracepoint yet, then it is cleared when it is.
@@ -346,6 +348,7 @@ enum {
TRACE_EVENT_FL_KPROBE = (1 << TRACE_EVENT_FL_KPROBE_BIT),
TRACE_EVENT_FL_UPROBE = (1 << TRACE_EVENT_FL_UPROBE_BIT),
TRACE_EVENT_FL_EPROBE = (1 << TRACE_EVENT_FL_EPROBE_BIT),
+ TRACE_EVENT_FL_FPROBE = (1 << TRACE_EVENT_FL_FPROBE_BIT),
TRACE_EVENT_FL_CUSTOM = (1 << TRACE_EVENT_FL_CUSTOM_BIT),
};
@@ -650,6 +650,20 @@ config BLK_DEV_IO_TRACE
If unsure, say N.
+config FPROBE_EVENTS
+ depends on FPROBE
+ depends on HAVE_REGS_AND_STACK_ACCESS_API
+ bool "Enable fprobe-based dynamic events"
+ select TRACING
+ select PROBE_EVENTS
+ select DYNAMIC_EVENTS
+ default y
+ help
+ This allows user to add tracing events on the function entry and
+ exit via ftrace interface. The syntax is same as the kprobe events
+ and the kprobe events on function entry and exit will be
+ transparently converted to this fprobe events.
+
config KPROBE_EVENTS
depends on KPROBES
depends on HAVE_REGS_AND_STACK_ACCESS_API
@@ -104,6 +104,7 @@ obj-$(CONFIG_BOOTTIME_TRACING) += trace_boot.o
obj-$(CONFIG_FTRACE_RECORD_RECURSION) += trace_recursion_record.o
obj-$(CONFIG_FPROBE) += fprobe.o
obj-$(CONFIG_RETHOOK) += rethook.o
+obj-$(CONFIG_FPROBE_EVENTS) += trace_fprobe.o
obj-$(CONFIG_TRACEPOINT_BENCHMARK) += trace_benchmark.o
obj-$(CONFIG_RV) += rv/
@@ -305,6 +305,14 @@ int register_fprobe_syms(struct fprobe *fp, const char **syms, int num)
}
EXPORT_SYMBOL_GPL(register_fprobe_syms);
+bool fprobe_is_registered(struct fprobe *fp)
+{
+ if (!fp || (fp->ops.saved_func != fprobe_handler &&
+ fp->ops.saved_func != fprobe_kprobe_handler))
+ return false;
+ return true;
+}
+
/**
* unregister_fprobe() - Unregister fprobe from ftrace
* @fp: A fprobe data structure to be unregistered.
@@ -317,8 +325,7 @@ int unregister_fprobe(struct fprobe *fp)
{
int ret;
- if (!fp || (fp->ops.saved_func != fprobe_handler &&
- fp->ops.saved_func != fprobe_kprobe_handler))
+ if (!fprobe_is_registered(fp))
return -EINVAL;
/*
@@ -5644,10 +5644,16 @@ static const char readme_msg[] =
" uprobe_events\t\t- Create/append/remove/show the userspace dynamic events\n"
"\t\t\t Write into this file to define/undefine new trace events.\n"
#endif
-#if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS)
+#if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS) || \
+ defined(CONFIG_FPROBE_EVENTS)
"\t accepts: event-definitions (one definition per line)\n"
+#if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS)
"\t Format: p[:[<group>/][<event>]] <place> [<args>]\n"
"\t r[maxactive][:[<group>/][<event>]] <place> [<args>]\n"
+#endif
+#ifdef CONFIG_FPROBE_EVENTS
+ "\t f[:[<group>/][<event>]] <func-name>[%return] [<args>]\n"
+#endif
#ifdef CONFIG_HIST_TRIGGERS
"\t s:[synthetic/]<event> <field> [<field>]\n"
#endif
@@ -148,6 +148,17 @@ struct kretprobe_trace_entry_head {
unsigned long ret_ip;
};
+struct fentry_trace_entry_head {
+ struct trace_entry ent;
+ unsigned long ip;
+};
+
+struct fexit_trace_entry_head {
+ struct trace_entry ent;
+ unsigned long func;
+ unsigned long ret_ip;
+};
+
#define TRACE_BUF_SIZE 1024
struct trace_array;
new file mode 100644
@@ -0,0 +1,1053 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Fprobe-based tracing events
+ * Copyright (C) 2022 Google LLC.
+ */
+#define pr_fmt(fmt) "trace_fprobe: " fmt
+
+#include <linux/fprobe.h>
+#include <linux/module.h>
+#include <linux/rculist.h>
+#include <linux/security.h>
+#include <linux/uaccess.h>
+
+#include "trace_dynevent.h"
+#include "trace_probe.h"
+#include "trace_probe_kernel.h"
+#include "trace_probe_tmpl.h"
+
+#define FPROBE_EVENT_SYSTEM "fprobes"
+#define RETHOOK_MAXACTIVE_MAX 4096
+
+static int trace_fprobe_create(const char *raw_command);
+static int trace_fprobe_show(struct seq_file *m, struct dyn_event *ev);
+static int trace_fprobe_release(struct dyn_event *ev);
+static bool trace_fprobe_is_busy(struct dyn_event *ev);
+static bool trace_fprobe_match(const char *system, const char *event,
+ int argc, const char **argv, struct dyn_event *ev);
+
+static struct dyn_event_operations trace_fprobe_ops = {
+ .create = trace_fprobe_create,
+ .show = trace_fprobe_show,
+ .is_busy = trace_fprobe_is_busy,
+ .free = trace_fprobe_release,
+ .match = trace_fprobe_match,
+};
+
+/*
+ * Fprobe event core functions
+ */
+struct trace_fprobe {
+ struct dyn_event devent;
+ struct fprobe fp;
+ const char *symbol;
+ struct trace_probe tp;
+};
+
+static bool is_trace_fprobe(struct dyn_event *ev)
+{
+ return ev->ops == &trace_fprobe_ops;
+}
+
+static struct trace_fprobe *to_trace_fprobe(struct dyn_event *ev)
+{
+ return container_of(ev, struct trace_fprobe, devent);
+}
+
+/**
+ * for_each_trace_fprobe - iterate over the trace_fprobe list
+ * @pos: the struct trace_fprobe * for each entry
+ * @dpos: the struct dyn_event * to use as a loop cursor
+ */
+#define for_each_trace_fprobe(pos, dpos) \
+ for_each_dyn_event(dpos) \
+ if (is_trace_fprobe(dpos) && (pos = to_trace_fprobe(dpos)))
+
+static bool trace_fprobe_is_return(struct trace_fprobe *tf)
+{
+ return tf->fp.exit_handler != NULL;
+}
+
+static const char *trace_fprobe_symbol(struct trace_fprobe *tf)
+{
+ return tf->symbol ? tf->symbol : "unknown";
+}
+
+static bool trace_fprobe_is_busy(struct dyn_event *ev)
+{
+ struct trace_fprobe *tf = to_trace_fprobe(ev);
+
+ return trace_probe_is_enabled(&tf->tp);
+}
+
+static bool trace_fprobe_match_command_head(struct trace_fprobe *tf,
+ int argc, const char **argv)
+{
+ char buf[MAX_ARGSTR_LEN + 1];
+
+ if (!argc)
+ return true;
+
+ snprintf(buf, sizeof(buf), "%s", trace_fprobe_symbol(tf));
+ if (strcmp(buf, argv[0]))
+ return false;
+ argc--; argv++;
+
+ return trace_probe_match_command_args(&tf->tp, argc, argv);
+}
+
+static bool trace_fprobe_match(const char *system, const char *event,
+ int argc, const char **argv, struct dyn_event *ev)
+{
+ struct trace_fprobe *tf = to_trace_fprobe(ev);
+
+ return (event[0] == '\0' ||
+ strcmp(trace_probe_name(&tf->tp), event) == 0) &&
+ (!system || strcmp(trace_probe_group_name(&tf->tp), system) == 0) &&
+ trace_fprobe_match_command_head(tf, argc, argv);
+}
+
+static bool trace_fprobe_is_registered(struct trace_fprobe *tf)
+{
+ return fprobe_is_registered(&tf->fp);
+}
+
+/* Note that we don't verify it, since the code does not come from user space */
+static int
+process_fetch_insn(struct fetch_insn *code, void *rec, void *dest,
+ void *base)
+{
+ struct pt_regs *regs = rec;
+ unsigned long val;
+
+retry:
+ /* 1st stage: get value from context */
+ switch (code->op) {
+ case FETCH_OP_REG:
+ val = regs_get_register(regs, code->param);
+ break;
+ case FETCH_OP_STACK:
+ val = regs_get_kernel_stack_nth(regs, code->param);
+ break;
+ case FETCH_OP_STACKP:
+ val = kernel_stack_pointer(regs);
+ break;
+ case FETCH_OP_RETVAL:
+ val = regs_return_value(regs);
+ break;
+ case FETCH_OP_IMM:
+ val = code->immediate;
+ break;
+ case FETCH_OP_COMM:
+ val = (unsigned long)current->comm;
+ break;
+ case FETCH_OP_DATA:
+ val = (unsigned long)code->data;
+ break;
+#ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
+ case FETCH_OP_ARG:
+ val = regs_get_kernel_argument(regs, code->param);
+ break;
+#endif
+ case FETCH_NOP_SYMBOL: /* Ignore a place holder */
+ code++;
+ goto retry;
+ default:
+ return -EILSEQ;
+ }
+ code++;
+
+ return process_fetch_insn_bottom(code, val, dest, base);
+}
+NOKPROBE_SYMBOL(process_fetch_insn)
+
+/* function entry handler */
+static nokprobe_inline void
+__fentry_trace_func(struct trace_fprobe *tf, unsigned long entry_ip,
+ struct pt_regs *regs,
+ struct trace_event_file *trace_file)
+{
+ struct fentry_trace_entry_head *entry;
+ struct trace_event_call *call = trace_probe_event_call(&tf->tp);
+ struct trace_event_buffer fbuffer;
+ int dsize;
+
+ WARN_ON(call != trace_file->event_call);
+
+ if (trace_trigger_soft_disabled(trace_file))
+ return;
+
+ dsize = __get_data_size(&tf->tp, regs);
+
+ entry = trace_event_buffer_reserve(&fbuffer, trace_file,
+ sizeof(*entry) + tf->tp.size + dsize);
+ if (!entry)
+ return;
+
+ fbuffer.regs = regs;
+ entry = fbuffer.entry = ring_buffer_event_data(fbuffer.event);
+ entry->ip = entry_ip;
+ store_trace_args(&entry[1], &tf->tp, regs, sizeof(*entry), dsize);
+
+ trace_event_buffer_commit(&fbuffer);
+}
+
+static void
+fentry_trace_func(struct trace_fprobe *tf, unsigned long entry_ip,
+ struct pt_regs *regs)
+{
+ struct event_file_link *link;
+
+ trace_probe_for_each_link_rcu(link, &tf->tp)
+ __fentry_trace_func(tf, entry_ip, regs, link->file);
+}
+NOKPROBE_SYMBOL(fentry_trace_func);
+
+/* Kretprobe handler */
+static nokprobe_inline void
+__fexit_trace_func(struct trace_fprobe *tf, unsigned long entry_ip,
+ unsigned long ret_ip, struct pt_regs *regs,
+ struct trace_event_file *trace_file)
+{
+ struct fexit_trace_entry_head *entry;
+ struct trace_event_buffer fbuffer;
+ struct trace_event_call *call = trace_probe_event_call(&tf->tp);
+ int dsize;
+
+ WARN_ON(call != trace_file->event_call);
+
+ if (trace_trigger_soft_disabled(trace_file))
+ return;
+
+ dsize = __get_data_size(&tf->tp, regs);
+
+ entry = trace_event_buffer_reserve(&fbuffer, trace_file,
+ sizeof(*entry) + tf->tp.size + dsize);
+ if (!entry)
+ return;
+
+ fbuffer.regs = regs;
+ entry = fbuffer.entry = ring_buffer_event_data(fbuffer.event);
+ entry->func = entry_ip;
+ entry->ret_ip = ret_ip;
+ store_trace_args(&entry[1], &tf->tp, regs, sizeof(*entry), dsize);
+
+ trace_event_buffer_commit(&fbuffer);
+}
+
+static void
+fexit_trace_func(struct trace_fprobe *tf, unsigned long entry_ip,
+ unsigned long ret_ip, struct pt_regs *regs)
+{
+ struct event_file_link *link;
+
+ trace_probe_for_each_link_rcu(link, &tf->tp)
+ __fexit_trace_func(tf, entry_ip, ret_ip, regs, link->file);
+}
+NOKPROBE_SYMBOL(fexit_trace_func);
+
+#ifdef CONFIG_PERF_EVENTS
+
+static int fentry_perf_func(struct trace_fprobe *tf, unsigned long entry_ip,
+ struct pt_regs *regs)
+{
+ struct trace_event_call *call = trace_probe_event_call(&tf->tp);
+ struct fentry_trace_entry_head *entry;
+ struct hlist_head *head;
+ int size, __size, dsize;
+ int rctx;
+
+ head = this_cpu_ptr(call->perf_events);
+ if (hlist_empty(head))
+ return 0;
+
+ dsize = __get_data_size(&tf->tp, regs);
+ __size = sizeof(*entry) + tf->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 = entry_ip;
+ memset(&entry[1], 0, dsize);
+ store_trace_args(&entry[1], &tf->tp, regs, sizeof(*entry), dsize);
+ perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
+ head, NULL);
+ return 0;
+}
+NOKPROBE_SYMBOL(fentry_perf_func);
+
+static void
+fexit_perf_func(struct trace_fprobe *tf, unsigned long entry_ip,
+ unsigned long ret_ip, struct pt_regs *regs)
+{
+ struct trace_event_call *call = trace_probe_event_call(&tf->tp);
+ struct fexit_trace_entry_head *entry;
+ struct hlist_head *head;
+ int size, __size, dsize;
+ int rctx;
+
+ head = this_cpu_ptr(call->perf_events);
+ if (hlist_empty(head))
+ return;
+
+ dsize = __get_data_size(&tf->tp, regs);
+ __size = sizeof(*entry) + tf->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 = entry_ip;
+ entry->ret_ip = ret_ip;
+ store_trace_args(&entry[1], &tf->tp, regs, sizeof(*entry), dsize);
+ perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
+ head, NULL);
+}
+NOKPROBE_SYMBOL(fexit_perf_func);
+#endif /* CONFIG_PERF_EVENTS */
+
+static int fentry_dispatcher(struct fprobe *fp, unsigned long entry_ip,
+ unsigned long ret_ip, struct pt_regs *regs,
+ void *entry_data)
+{
+ struct trace_fprobe *tf = container_of(fp, struct trace_fprobe, fp);
+ int ret = 0;
+
+ if (trace_probe_test_flag(&tf->tp, TP_FLAG_TRACE))
+ fentry_trace_func(tf, entry_ip, regs);
+#ifdef CONFIG_PERF_EVENTS
+ if (trace_probe_test_flag(&tf->tp, TP_FLAG_PROFILE))
+ ret = fentry_perf_func(tf, entry_ip, regs);
+#endif
+ return ret;
+}
+NOKPROBE_SYMBOL(fentry_dispatcher);
+
+static void fexit_dispatcher(struct fprobe *fp, unsigned long entry_ip,
+ unsigned long ret_ip, struct pt_regs *regs,
+ void *entry_data)
+{
+ struct trace_fprobe *tf = container_of(fp, struct trace_fprobe, fp);
+
+ if (trace_probe_test_flag(&tf->tp, TP_FLAG_TRACE))
+ fexit_trace_func(tf, entry_ip, ret_ip, regs);
+#ifdef CONFIG_PERF_EVENTS
+ if (trace_probe_test_flag(&tf->tp, TP_FLAG_PROFILE))
+ fexit_perf_func(tf, entry_ip, ret_ip, regs);
+#endif
+}
+NOKPROBE_SYMBOL(fexit_dispatcher);
+
+static void free_trace_fprobe(struct trace_fprobe *tf)
+{
+ if (tf) {
+ trace_probe_cleanup(&tf->tp);
+ kfree(tf->symbol);
+ kfree(tf);
+ }
+}
+
+/*
+ * Allocate new trace_probe and initialize it (including fprobe).
+ */
+static struct trace_fprobe *alloc_trace_fprobe(const char *group,
+ const char *event,
+ const char *symbol,
+ int maxactive,
+ int nargs, bool is_return)
+{
+ struct trace_fprobe *tf;
+ int ret = -ENOMEM;
+
+ tf = kzalloc(struct_size(tf, tp.args, nargs), GFP_KERNEL);
+ if (!tf)
+ return ERR_PTR(ret);
+
+ tf->symbol = kstrdup(symbol, GFP_KERNEL);
+ if (!tf->symbol)
+ goto error;
+
+ if (is_return)
+ tf->fp.exit_handler = fexit_dispatcher;
+ else
+ tf->fp.entry_handler = fentry_dispatcher;
+
+ tf->fp.nr_maxactive = maxactive;
+
+ ret = trace_probe_init(&tf->tp, event, group, false);
+ if (ret < 0)
+ goto error;
+
+ dyn_event_init(&tf->devent, &trace_fprobe_ops);
+ return tf;
+error:
+ free_trace_fprobe(tf);
+ return ERR_PTR(ret);
+}
+
+static struct trace_fprobe *find_trace_fprobe(const char *event,
+ const char *group)
+{
+ struct dyn_event *pos;
+ struct trace_fprobe *tf;
+
+ for_each_trace_fprobe(tf, pos)
+ if (strcmp(trace_probe_name(&tf->tp), event) == 0 &&
+ strcmp(trace_probe_group_name(&tf->tp), group) == 0)
+ return tf;
+ return NULL;
+}
+
+static inline int __enable_trace_fprobe(struct trace_fprobe *tf)
+{
+ if (trace_fprobe_is_registered(tf))
+ enable_fprobe(&tf->fp);
+
+ return 0;
+}
+
+static void __disable_trace_fprobe(struct trace_probe *tp)
+{
+ struct trace_fprobe *tf;
+
+ list_for_each_entry(tf, trace_probe_probe_list(tp), tp.list) {
+ if (!trace_fprobe_is_registered(tf))
+ continue;
+ disable_fprobe(&tf->fp);
+ }
+}
+
+/*
+ * Enable trace_probe
+ * if the file is NULL, enable "perf" handler, or enable "trace" handler.
+ */
+static int enable_trace_fprobe(struct trace_event_call *call,
+ struct trace_event_file *file)
+{
+ struct trace_probe *tp;
+ struct trace_fprobe *tf;
+ bool enabled;
+ int ret = 0;
+
+ tp = trace_probe_primary_from_call(call);
+ if (WARN_ON_ONCE(!tp))
+ return -ENODEV;
+ enabled = trace_probe_is_enabled(tp);
+
+ /* This also changes "enabled" state */
+ if (file) {
+ ret = trace_probe_add_file(tp, file);
+ if (ret)
+ return ret;
+ } else
+ trace_probe_set_flag(tp, TP_FLAG_PROFILE);
+
+ if (!enabled) {
+ list_for_each_entry(tf, trace_probe_probe_list(tp), tp.list) {
+ /* TODO: check the fprobe is gone */
+ __enable_trace_fprobe(tf);
+ }
+ }
+
+ return 0;
+}
+
+/*
+ * Disable trace_probe
+ * if the file is NULL, disable "perf" handler, or disable "trace" handler.
+ */
+static int disable_trace_fprobe(struct trace_event_call *call,
+ struct trace_event_file *file)
+{
+ struct trace_probe *tp;
+
+ tp = trace_probe_primary_from_call(call);
+ if (WARN_ON_ONCE(!tp))
+ return -ENODEV;
+
+ if (file) {
+ if (!trace_probe_get_file_link(tp, file))
+ return -ENOENT;
+ if (!trace_probe_has_single_file(tp))
+ goto out;
+ trace_probe_clear_flag(tp, TP_FLAG_TRACE);
+ } else
+ trace_probe_clear_flag(tp, TP_FLAG_PROFILE);
+
+ 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;
+
+ /* 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));
+ }
+}
+
+/* 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_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;
+}
+
+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]
+ *
+ * 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, ret = 0;
+ bool is_return = false;
+ char *symbol = NULL, *tmp = NULL;
+ const char *event = NULL, *group = FPROBE_EVENT_SYSTEM;
+ int maxactive = 0;
+ char buf[MAX_EVENT_NAME_LEN];
+ char gbuf[MAX_EVENT_NAME_LEN];
+ unsigned int flags = TPARG_FL_KERNEL;
+
+ if (argv[0][0] != 'f' || argc < 2)
+ return -ECANCELED;
+
+ 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 specified */
+ symbol = kstrdup(argv[1], GFP_KERNEL);
+ if (!symbol)
+ return -ENOMEM;
+
+ tmp = strchr(symbol, '%');
+ if (tmp) {
+ if (!strcmp(tmp, "%return")) {
+ *tmp = '\0';
+ is_return = true;
+ } else {
+ trace_probe_log_err(tmp - symbol, BAD_ADDR_SUFFIX);
+ goto parse_error;
+ }
+ }
+ if (!is_return && maxactive) {
+ trace_probe_log_set_index(0);
+ trace_probe_log_err(1, BAD_MAXACT_TYPE);
+ goto parse_error;
+ }
+
+ flags |= TPARG_FL_FENTRY;
+ if (is_return)
+ flags |= TPARG_FL_RETURN;
+
+ 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 */
+ snprintf(buf, MAX_EVENT_NAME_LEN, "%s__%s", symbol,
+ is_return ? "exit" : "entry");
+ sanitize_event_name(buf);
+ event = buf;
+ }
+
+ /* setup a probe */
+ tf = alloc_trace_fprobe(group, event, symbol, maxactive,
+ argc - 2, 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 */
+ }
+ argc -= 2; argv += 2;
+
+ /* parse arguments */
+ for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
+ trace_probe_log_set_index(i + 2);
+ ret = traceprobe_parse_probe_arg(&tf->tp, i, argv[i], flags);
+ 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:
+ trace_probe_log_clear();
+ 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;
+
+ 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;
+
+ return 0;
+}
+core_initcall(init_fprobe_trace_early);
@@ -764,7 +764,7 @@ static int __trace_kprobe_create(int argc, const char *argv[])
if (isdigit(argv[0][1])) {
if (!is_return) {
- trace_probe_log_err(1, MAXACT_NO_KPROBE);
+ trace_probe_log_err(1, BAD_MAXACT_TYPE);
goto parse_error;
}
if (event)
@@ -393,8 +393,8 @@ parse_probe_arg(char *arg, const struct fetch_type *type,
break;
case '%': /* named register */
- if (flags & TPARG_FL_TPOINT) {
- /* eprobes do not handle registers */
+ if (flags & (TPARG_FL_TPOINT | TPARG_FL_FPROBE)) {
+ /* eprobe and fprobe do not handle registers */
trace_probe_log_err(offs, BAD_VAR);
break;
}
@@ -362,7 +362,8 @@ int trace_probe_print_args(struct trace_seq *s, struct probe_arg *args, int nr_a
#define TPARG_FL_FENTRY BIT(2)
#define TPARG_FL_TPOINT BIT(3)
#define TPARG_FL_USER BIT(4)
-#define TPARG_FL_MASK GENMASK(4, 0)
+#define TPARG_FL_FPROBE BIT(5)
+#define TPARG_FL_MASK GENMASK(5, 0)
extern int traceprobe_parse_probe_arg(struct trace_probe *tp, int i,
const char *argv, unsigned int flags);
@@ -404,7 +405,7 @@ extern int traceprobe_define_arg_fields(struct trace_event_call *event_call,
C(REFCNT_OPEN_BRACE, "Reference counter brace is not closed"), \
C(BAD_REFCNT_SUFFIX, "Reference counter has wrong suffix"), \
C(BAD_UPROBE_OFFS, "Invalid uprobe offset"), \
- C(MAXACT_NO_KPROBE, "Maxactive is not for kprobe"), \
+ C(BAD_MAXACT_TYPE, "Maxactive is only for function exit"), \
C(BAD_MAXACT, "Invalid maxactive number"), \
C(MAXACT_TOO_BIG, "Maxactive is too big"), \
C(BAD_PROBE_ADDR, "Invalid probed address or symbol"), \
@@ -8,7 +8,7 @@ check_error() { # command-with-error-pos-by-^
}
if grep -q 'r\[maxactive\]' README; then
-check_error 'p^100 vfs_read' # MAXACT_NO_KPROBE
+check_error 'p^100 vfs_read' # BAD_MAXACT_TYPE
check_error 'r^1a111 vfs_read' # BAD_MAXACT
check_error 'r^100000 vfs_read' # MAXACT_TOO_BIG
fi