/*
- * kprobe based kernel tracer
+ * Kprobes-based tracing events
*
* Created by Masami Hiramatsu <mhiramat@redhat.com>
*
#define MAX_EVENT_NAME_LEN 64
#define KPROBE_EVENT_SYSTEM "kprobes"
-/* currently, trace_kprobe only supports X86. */
+/* Reserved field names */
+#define FIELD_STRING_IP "__probe_ip"
+#define FIELD_STRING_NARGS "__probe_nargs"
+#define FIELD_STRING_RETIP "__probe_ret_ip"
+#define FIELD_STRING_FUNC "__probe_func"
+
+const char *reserved_field_names[] = {
+ "common_type",
+ "common_flags",
+ "common_preempt_count",
+ "common_pid",
+ "common_tgid",
+ "common_lock_depth",
+ FIELD_STRING_IP,
+ FIELD_STRING_NARGS,
+ FIELD_STRING_RETIP,
+ FIELD_STRING_FUNC,
+};
struct fetch_func {
unsigned long (*func)(struct pt_regs *, void *);
return regs_return_value(regs);
}
-static __kprobes unsigned long fetch_ip(struct pt_regs *regs, void *dummy)
-{
- return instruction_pointer(regs);
-}
-
static __kprobes unsigned long fetch_stack_address(struct pt_regs *regs,
void *dummy)
{
}
/**
- * Kprobe tracer core functions
+ * Kprobe event core functions
*/
struct probe_arg {
int ret = -EINVAL;
if (ff->func == fetch_argument)
- ret = snprintf(buf, n, "a%lu", (unsigned long)ff->data);
+ ret = snprintf(buf, n, "$arg%lu", (unsigned long)ff->data);
else if (ff->func == fetch_register) {
const char *name;
name = regs_query_register_name((unsigned int)((long)ff->data));
ret = snprintf(buf, n, "%%%s", name);
} else if (ff->func == fetch_stack)
- ret = snprintf(buf, n, "s%lu", (unsigned long)ff->data);
+ ret = snprintf(buf, n, "$stack%lu", (unsigned long)ff->data);
else if (ff->func == fetch_memory)
ret = snprintf(buf, n, "@0x%p", ff->data);
else if (ff->func == fetch_symbol) {
struct symbol_cache *sc = ff->data;
- ret = snprintf(buf, n, "@%s%+ld", sc->symbol, sc->offset);
+ if (sc->offset)
+ ret = snprintf(buf, n, "@%s%+ld", sc->symbol,
+ sc->offset);
+ else
+ ret = snprintf(buf, n, "@%s", sc->symbol);
} else if (ff->func == fetch_retvalue)
- ret = snprintf(buf, n, "rv");
- else if (ff->func == fetch_ip)
- ret = snprintf(buf, n, "ra");
+ ret = snprintf(buf, n, "$retval");
else if (ff->func == fetch_stack_address)
- ret = snprintf(buf, n, "sa");
+ ret = snprintf(buf, n, "$stack");
else if (ff->func == fetch_indirect) {
struct indirect_fetch_data *id = ff->data;
size_t l = 0;
kfree(tp);
}
-static struct trace_probe *find_probe_event(const char *event)
+static struct trace_probe *find_probe_event(const char *event,
+ const char *group)
{
struct trace_probe *tp;
list_for_each_entry(tp, &probe_list, list)
- if (!strcmp(tp->call.name, event))
+ if (strcmp(tp->call.name, event) == 0 &&
+ strcmp(tp->call.system, group) == 0)
return tp;
return NULL;
}
mutex_lock(&probe_lock);
/* register as an event */
- old_tp = find_probe_event(tp->call.name);
+ old_tp = find_probe_event(tp->call.name, tp->call.system);
if (old_tp) {
/* delete old event */
unregister_trace_probe(old_tp);
#define PARAM_MAX_ARGS 16
#define PARAM_MAX_STACK (THREAD_SIZE / sizeof(unsigned long))
-static int parse_probe_arg(char *arg, struct fetch_func *ff, int is_return)
+static int parse_probe_vars(char *arg, struct fetch_func *ff, int is_return)
{
int ret = 0;
unsigned long param;
- long offset;
- char *tmp;
- switch (arg[0]) {
- case 'a': /* argument */
- ret = strict_strtoul(arg + 1, 10, ¶m);
+ if (strcmp(arg, "retval") == 0) {
+ if (is_return) {
+ ff->func = fetch_retvalue;
+ ff->data = NULL;
+ } else
+ ret = -EINVAL;
+ } else if (strncmp(arg, "stack", 5) == 0) {
+ if (arg[5] == '\0') {
+ ff->func = fetch_stack_address;
+ ff->data = NULL;
+ } else if (isdigit(arg[5])) {
+ ret = strict_strtoul(arg + 5, 10, ¶m);
+ if (ret || param > PARAM_MAX_STACK)
+ ret = -EINVAL;
+ else {
+ ff->func = fetch_stack;
+ ff->data = (void *)param;
+ }
+ } else
+ ret = -EINVAL;
+ } else if (strncmp(arg, "arg", 3) == 0 && isdigit(arg[3])) {
+ ret = strict_strtoul(arg + 3, 10, ¶m);
if (ret || param > PARAM_MAX_ARGS)
ret = -EINVAL;
else {
ff->func = fetch_argument;
ff->data = (void *)param;
}
- break;
- case 'r': /* retval or retaddr */
- if (is_return && arg[1] == 'v') {
- ff->func = fetch_retvalue;
- ff->data = NULL;
- } else if (is_return && arg[1] == 'a') {
- ff->func = fetch_ip;
- ff->data = NULL;
- } else
- ret = -EINVAL;
+ } else
+ ret = -EINVAL;
+ return ret;
+}
+
+/* Recursive argument parser */
+static int __parse_probe_arg(char *arg, struct fetch_func *ff, int is_return)
+{
+ int ret = 0;
+ unsigned long param;
+ long offset;
+ char *tmp;
+
+ switch (arg[0]) {
+ case '$':
+ ret = parse_probe_vars(arg + 1, ff, is_return);
break;
case '%': /* named register */
ret = regs_query_register_offset(arg + 1);
ret = 0;
}
break;
- case 's': /* stack */
- if (arg[1] == 'a') {
- ff->func = fetch_stack_address;
- ff->data = NULL;
- } else {
- ret = strict_strtoul(arg + 1, 10, ¶m);
- if (ret || param > PARAM_MAX_STACK)
- ret = -EINVAL;
- else {
- ff->func = fetch_stack;
- ff->data = (void *)param;
- }
- }
- break;
case '@': /* memory or symbol */
if (isdigit(arg[1])) {
ret = strict_strtoul(arg + 1, 0, ¶m);
ret = split_symbol_offset(arg + 1, &offset);
if (ret)
break;
- ff->data = alloc_symbol_cache(arg + 1,
- offset);
+ ff->data = alloc_symbol_cache(arg + 1, offset);
if (ff->data)
ff->func = fetch_symbol;
else
if (!id)
return -ENOMEM;
id->offset = offset;
- ret = parse_probe_arg(arg, &id->orig, is_return);
+ ret = __parse_probe_arg(arg, &id->orig, is_return);
if (ret)
kfree(id);
else {
return ret;
}
+/* String length checking wrapper */
+static int parse_probe_arg(char *arg, struct fetch_func *ff, int is_return)
+{
+ if (strlen(arg) > MAX_ARGSTR_LEN) {
+ pr_info("Argument is too long.: %s\n", arg);
+ return -ENOSPC;
+ }
+ return __parse_probe_arg(arg, ff, is_return);
+}
+
+/* Return 1 if name is reserved or already used by another argument */
+static int conflict_field_name(const char *name,
+ struct probe_arg *args, int narg)
+{
+ int i;
+ for (i = 0; i < ARRAY_SIZE(reserved_field_names); i++)
+ if (strcmp(reserved_field_names[i], name) == 0)
+ return 1;
+ for (i = 0; i < narg; i++)
+ if (strcmp(args[i].name, name) == 0)
+ return 1;
+ return 0;
+}
+
static int create_trace_probe(int argc, char **argv)
{
/*
* - Add kprobe: p[:[GRP/]EVENT] KSYM[+OFFS]|KADDR [FETCHARGS]
* - Add kretprobe: r[:[GRP/]EVENT] KSYM[+0] [FETCHARGS]
* Fetch args:
- * aN : fetch Nth of function argument. (N:0-)
- * rv : fetch return value
- * ra : fetch return address
- * sa : fetch stack address
- * sN : fetch Nth of stack (N:0-)
+ * $argN : fetch Nth of function argument. (N:0-)
+ * $retval : fetch return value
+ * $stack : fetch stack address
+ * $stackN : fetch Nth of stack (N:0-)
* @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
void *addr = NULL;
char buf[MAX_EVENT_NAME_LEN];
- if (argc < 2)
+ if (argc < 2) {
+ pr_info("Probe point is not specified.\n");
return -EINVAL;
+ }
if (argv[0][0] == 'p')
is_return = 0;
else if (argv[0][0] == 'r')
is_return = 1;
- else
+ else {
+ pr_info("Probe definition must be started with 'p' or 'r'.\n");
return -EINVAL;
+ }
if (argv[0][1] == ':') {
event = &argv[0][2];
}
if (isdigit(argv[1][0])) {
- if (is_return)
+ if (is_return) {
+ pr_info("Return probe point must be a symbol.\n");
return -EINVAL;
+ }
/* an address specified */
ret = strict_strtoul(&argv[0][2], 0, (unsigned long *)&addr);
- if (ret)
+ if (ret) {
+ pr_info("Failed to parse address.\n");
return ret;
+ }
} else {
/* a symbol specified */
symbol = argv[1];
/* TODO: support .init module functions */
ret = split_symbol_offset(symbol, &offset);
- if (ret)
+ if (ret) {
+ pr_info("Failed to parse symbol.\n");
return ret;
- if (offset && is_return)
+ }
+ if (offset && is_return) {
+ pr_info("Return probe must be used without offset.\n");
return -EINVAL;
+ }
}
argc -= 2; argv += 2;
}
tp = alloc_trace_probe(group, event, addr, symbol, offset, argc,
is_return);
- if (IS_ERR(tp))
+ if (IS_ERR(tp)) {
+ pr_info("Failed to allocate trace_probe.(%d)\n",
+ (int)PTR_ERR(tp));
return PTR_ERR(tp);
+ }
/* parse arguments */
ret = 0;
*arg++ = '\0';
else
arg = argv[i];
- tp->args[i].name = kstrdup(argv[i], GFP_KERNEL);
- /* Parse fetch argument */
- if (strlen(arg) > MAX_ARGSTR_LEN) {
- pr_info("Argument%d(%s) is too long.\n", i, arg);
- ret = -ENOSPC;
+ if (conflict_field_name(argv[i], tp->args, i)) {
+ pr_info("Argument%d name '%s' conflicts with "
+ "another field.\n", i, argv[i]);
+ ret = -EINVAL;
+ goto error;
+ }
+
+ tp->args[i].name = kstrdup(argv[i], GFP_KERNEL);
+ if (!tp->args[i].name) {
+ pr_info("Failed to allocate argument%d name '%s'.\n",
+ i, argv[i]);
+ ret = -ENOMEM;
goto error;
}
+
+ /* Parse fetch argument */
ret = parse_probe_arg(arg, &tp->args[i].fetch, is_return);
- if (ret)
+ if (ret) {
+ pr_info("Parse error at argument%d. (%d)\n", i, ret);
+ kfree(tp->args[i].name);
goto error;
+ }
+
+ tp->nr_args++;
}
- tp->nr_args = i;
ret = register_trace_probe(tp);
if (ret)
char buf[MAX_ARGSTR_LEN + 1];
seq_printf(m, "%c", probe_is_return(tp) ? 'r' : 'p');
- seq_printf(m, ":%s", tp->call.name);
+ seq_printf(m, ":%s/%s", tp->call.system, tp->call.name);
- if (tp->symbol)
+ if (!tp->symbol)
+ seq_printf(m, " 0x%p", tp->rp.kp.addr);
+ else if (tp->rp.kp.offset)
seq_printf(m, " %s+%u", probe_symbol(tp), tp->rp.kp.offset);
else
- seq_printf(m, " 0x%p", tp->rp.kp.addr);
+ seq_printf(m, " %s", probe_symbol(tp));
for (i = 0; i < tp->nr_args; i++) {
ret = probe_arg_string(buf, MAX_ARGSTR_LEN, &tp->args[i].fetch);
if (!ret)
return ret;
- DEFINE_FIELD(unsigned long, ip, "ip", 0);
- DEFINE_FIELD(int, nargs, "nargs", 1);
+ DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0);
+ DEFINE_FIELD(int, nargs, FIELD_STRING_NARGS, 1);
/* Set argument names as fields */
for (i = 0; i < tp->nr_args; i++)
DEFINE_FIELD(unsigned long, args[i], tp->args[i].name, 0);
if (!ret)
return ret;
- DEFINE_FIELD(unsigned long, func, "func", 0);
- DEFINE_FIELD(unsigned long, ret_ip, "ret_ip", 0);
- DEFINE_FIELD(int, nargs, "nargs", 1);
+ DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0);
+ DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0);
+ DEFINE_FIELD(int, nargs, FIELD_STRING_NARGS, 1);
/* Set argument names as fields */
for (i = 0; i < tp->nr_args; i++)
DEFINE_FIELD(unsigned long, args[i], tp->args[i].name, 0);
int ret, i;
struct trace_probe *tp = (struct trace_probe *)call->data;
- SHOW_FIELD(unsigned long, ip, "ip");
- SHOW_FIELD(int, nargs, "nargs");
+ SHOW_FIELD(unsigned long, ip, FIELD_STRING_IP);
+ SHOW_FIELD(int, nargs, FIELD_STRING_NARGS);
/* Show fields */
for (i = 0; i < tp->nr_args; i++)
SHOW_FIELD(unsigned long, args[i], tp->args[i].name);
trace_seq_puts(s, "\n");
- return __probe_event_show_format(s, tp, "(%lx)", "REC->ip");
+ return __probe_event_show_format(s, tp, "(%lx)",
+ "REC->" FIELD_STRING_IP);
}
static int kretprobe_event_show_format(struct ftrace_event_call *call,
int ret, i;
struct trace_probe *tp = (struct trace_probe *)call->data;
- SHOW_FIELD(unsigned long, func, "func");
- SHOW_FIELD(unsigned long, ret_ip, "ret_ip");
- SHOW_FIELD(int, nargs, "nargs");
+ SHOW_FIELD(unsigned long, func, FIELD_STRING_FUNC);
+ SHOW_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP);
+ SHOW_FIELD(int, nargs, FIELD_STRING_NARGS);
/* Show fields */
for (i = 0; i < tp->nr_args; i++)
trace_seq_puts(s, "\n");
return __probe_event_show_format(s, tp, "(%lx <- %lx)",
- "REC->func, REC->ret_ip");
+ "REC->" FIELD_STRING_FUNC
+ ", REC->" FIELD_STRING_RETIP);
}
#ifdef CONFIG_EVENT_PROFILE
struct trace_entry *ent;
int size, __size, i, pc, __cpu;
unsigned long irq_flags;
+ char *trace_buf;
char *raw_data;
+ int rctx;
pc = preempt_count();
__size = SIZEOF_KPROBE_TRACE_ENTRY(tp->nr_args);
* This also protects the rcu read side
*/
local_irq_save(irq_flags);
+
+ rctx = perf_swevent_get_recursion_context();
+ if (rctx < 0)
+ goto end_recursion;
+
__cpu = smp_processor_id();
if (in_nmi())
- raw_data = rcu_dereference(trace_profile_buf_nmi);
+ trace_buf = rcu_dereference(perf_trace_buf_nmi);
else
- raw_data = rcu_dereference(trace_profile_buf);
+ trace_buf = rcu_dereference(perf_trace_buf);
- if (!raw_data)
+ if (!trace_buf)
goto end;
- raw_data = per_cpu_ptr(raw_data, __cpu);
+ raw_data = per_cpu_ptr(trace_buf, __cpu);
+
/* Zero dead bytes from alignment to avoid buffer leak to userspace */
*(u64 *)(&raw_data[size - sizeof(u64)]) = 0ULL;
entry = (struct kprobe_trace_entry *)raw_data;
for (i = 0; i < tp->nr_args; i++)
entry->args[i] = call_fetch(&tp->args[i].fetch, regs);
perf_tp_event(call->id, entry->ip, 1, entry, size);
+
end:
+ perf_swevent_put_recursion_context(rctx);
+end_recursion:
local_irq_restore(irq_flags);
+
return 0;
}
struct trace_entry *ent;
int size, __size, i, pc, __cpu;
unsigned long irq_flags;
+ char *trace_buf;
char *raw_data;
+ int rctx;
pc = preempt_count();
__size = SIZEOF_KRETPROBE_TRACE_ENTRY(tp->nr_args);
* This also protects the rcu read side
*/
local_irq_save(irq_flags);
+
+ rctx = perf_swevent_get_recursion_context();
+ if (rctx < 0)
+ goto end_recursion;
+
__cpu = smp_processor_id();
if (in_nmi())
- raw_data = rcu_dereference(trace_profile_buf_nmi);
+ trace_buf = rcu_dereference(perf_trace_buf_nmi);
else
- raw_data = rcu_dereference(trace_profile_buf);
+ trace_buf = rcu_dereference(perf_trace_buf);
- if (!raw_data)
+ if (!trace_buf)
goto end;
- raw_data = per_cpu_ptr(raw_data, __cpu);
+ raw_data = per_cpu_ptr(trace_buf, __cpu);
+
/* Zero dead bytes from alignment to avoid buffer leak to userspace */
*(u64 *)(&raw_data[size - sizeof(u64)]) = 0ULL;
entry = (struct kretprobe_trace_entry *)raw_data;
for (i = 0; i < tp->nr_args; i++)
entry->args[i] = call_fetch(&tp->args[i].fetch, regs);
perf_tp_event(call->id, entry->ret_ip, 1, entry, size);
+
end:
+ perf_swevent_put_recursion_context(rctx);
+end_recursion:
local_irq_restore(irq_flags);
+
return 0;
}
pr_info("Testing kprobe tracing: ");
ret = command_trace_probe("p:testprobe kprobe_trace_selftest_target "
- "a1 a2 a3 a4 a5 a6");
+ "$arg1 $arg2 $arg3 $arg4 $stack $stack0");
if (WARN_ON_ONCE(ret))
pr_warning("error enabling function entry\n");
ret = command_trace_probe("r:testprobe2 kprobe_trace_selftest_target "
- "ra rv");
+ "$retval");
if (WARN_ON_ONCE(ret))
pr_warning("error enabling function return\n");