Merge tag 'probes-v6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull probes updates from Masami Hiramatsu:

 - fprobe: Pass return address to the fprobe entry/exit callbacks so
   that the callbacks don't need to analyze pt_regs/stack to find the
   function return address.

 - kprobe events: cleanup usage of TPARG_FL_FENTRY and TPARG_FL_RETURN
   flags so that those are not set at once.

 - fprobe events:
      - Add a new fprobe events for tracing arbitrary function entry and
        exit as a trace event.
      - Add a new tracepoint events for tracing raw tracepoint as a
        trace event. This allows user to trace non user-exposed
        tracepoints.
      - Move eprobe's event parser code into probe event common file.
      - Introduce BTF (BPF type format) support to kernel probe (kprobe,
        fprobe and tracepoint probe) events so that user can specify
        traced function arguments by name. This also applies the type of
        argument when fetching the argument.
      - Introduce '$arg*' wildcard support if BTF is available. This
        expands the '$arg*' meta argument to all function argument
        automatically.
      - Check the return value types by BTF. If the function returns
        'void', '$retval' is rejected.
      - Add some selftest script for fprobe events, tracepoint events
        and BTF support.
      - Update documentation about the fprobe events.
      - Some fixes for above features, document and selftests.

 - selftests for ftrace (in addition to the new fprobe events):
      - Add a test case for multiple consecutive probes in a function
        which checks if ftrace based kprobe, optimized kprobe and normal
        kprobe can be defined in the same target function.
      - Add a test case for optimized probe, which checks whether kprobe
        can be optimized or not.

* tag 'probes-v6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  tracing/probes: Fix tracepoint event with $arg* to fetch correct argument
  Documentation: Fix typo of reference file name
  tracing/probes: Fix to return NULL and keep using current argc
  selftests/ftrace: Add new test case which checks for optimized probes
  selftests/ftrace: Add new test case which adds multiple consecutive probes in a function
  Documentation: tracing/probes: Add fprobe event tracing document
  selftests/ftrace: Add BTF arguments test cases
  selftests/ftrace: Add tracepoint probe test case
  tracing/probes: Add BTF retval type support
  tracing/probes: Add $arg* meta argument for all function args
  tracing/probes: Support function parameters if BTF is available
  tracing/probes: Move event parameter fetching code to common parser
  tracing/probes: Add tracepoint support on fprobe_events
  selftests/ftrace: Add fprobe related testcases
  tracing/probes: Add fprobe events for tracing function entry and exit.
  tracing/probes: Avoid setting TPARG_FL_FENTRY and TPARG_FL_RETURN
  fprobe: Pass return address to the handlers

Documentation/trace/index.rst

@@ -13,6 +13,7 @@ Linux Tracing Technologies
    kprobes
    kprobetrace
    uprobetracer
+   fprobetrace
    tracepoints
    events
    events-kmem

Documentation/trace/kprobetrace.rst

@@ -66,6 +66,8 @@ Synopsis of kprobe_events
   (\*3) this is useful for fetching a field of data structures.
   (\*4) "u" means user-space dereference. See :ref:`user_mem_access`.
 
+.. _kprobetrace_types:
+
 Types
 -----
 Several types are supported for fetchargs. Kprobe tracer will access memory

include/linux/fprobe.h

@@ -35,9 +35,11 @@ struct fprobe {
 	int			nr_maxactive;
 
 	int (*entry_handler)(struct fprobe *fp, unsigned long entry_ip,
-			     struct pt_regs *regs, void *entry_data);
+			     unsigned long ret_ip, struct pt_regs *regs,
+			     void *entry_data);
 	void (*exit_handler)(struct fprobe *fp, unsigned long entry_ip,
-			     struct pt_regs *regs, void *entry_data);
+			     unsigned long ret_ip, struct pt_regs *regs,
+			     void *entry_data);
 };
 
 /* This fprobe is soft-disabled. */
@@ -64,6 +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)
 {
@@ -81,6 +84,10 @@ static inline int unregister_fprobe(struct fprobe *fp)
 {
 	return -EOPNOTSUPP;
 }
+static inline bool fprobe_is_registered(struct fprobe *fp)
+{
+	return false;
+}
 #endif
 
 /**

include/linux/rethook.h

@@ -14,7 +14,7 @@
 
 struct rethook_node;
 
-typedef void (*rethook_handler_t) (struct rethook_node *, void *, struct pt_regs *);
+typedef void (*rethook_handler_t) (struct rethook_node *, void *, unsigned long, struct pt_regs *);
 
 /**
  * struct rethook - The rethook management data structure.

include/linux/trace_events.h

@@ -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),
 };
 

include/linux/tracepoint-defs.h

@@ -35,6 +35,7 @@ struct tracepoint {
 	struct static_call_key *static_call_key;
 	void *static_call_tramp;
 	void *iterator;
+	void *probestub;
 	int (*regfunc)(void);
 	void (*unregfunc)(void);
 	struct tracepoint_func __rcu *funcs;

include/linux/tracepoint.h

@@ -303,6 +303,7 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p)
 	__section("__tracepoints_strings") = #_name;			\
 	extern struct static_call_key STATIC_CALL_KEY(tp_func_##_name);	\
 	int __traceiter_##_name(void *__data, proto);			\
+	void __probestub_##_name(void *__data, proto);			\
 	struct tracepoint __tracepoint_##_name	__used			\
 	__section("__tracepoints") = {					\
 		.name = __tpstrtab_##_name,				\
@@ -310,6 +311,7 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p)
 		.static_call_key = &STATIC_CALL_KEY(tp_func_##_name),	\
 		.static_call_tramp = STATIC_CALL_TRAMP_ADDR(tp_func_##_name), \
 		.iterator = &__traceiter_##_name,			\
+		.probestub = &__probestub_##_name,			\
 		.regfunc = _reg,					\
 		.unregfunc = _unreg,					\
 		.funcs = NULL };					\
@@ -330,6 +332,9 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p)
 		}							\
 		return 0;						\
 	}								\
+	void __probestub_##_name(void *__data, proto)			\
+	{								\
+	}								\
 	DEFINE_STATIC_CALL(tp_func_##_name, __traceiter_##_name);
 
 #define DEFINE_TRACE(name, proto, args)		\

kernel/kprobes.c

@@ -2127,6 +2127,7 @@ static int pre_handler_kretprobe(struct kprobe *p, struct pt_regs *regs)
 NOKPROBE_SYMBOL(pre_handler_kretprobe);
 
 static void kretprobe_rethook_handler(struct rethook_node *rh, void *data,
+				      unsigned long ret_addr,
 				      struct pt_regs *regs)
 {
 	struct kretprobe *rp = (struct kretprobe *)data;

kernel/trace/Kconfig

@@ -665,6 +665,32 @@ 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 PROBE_EVENTS_BTF_ARGS
+	depends on HAVE_FUNCTION_ARG_ACCESS_API
+	depends on FPROBE_EVENTS || KPROBE_EVENTS
+	depends on DEBUG_INFO_BTF && BPF_SYSCALL
+	bool "Support BTF function arguments for probe events"
+	default y
+	help
+	  The user can specify the arguments of the probe event using the names
+	  of the arguments of the probed function, when the probe location is a
+	  kernel function entry or a tracepoint.
+	  This is available only if BTF (BPF Type Format) support is enabled.
+
 config KPROBE_EVENTS
 	depends on KPROBES
 	depends on HAVE_REGS_AND_STACK_ACCESS_API

kernel/trace/Makefile

@@ -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/

kernel/trace/bpf_trace.c

@@ -2652,7 +2652,8 @@ kprobe_multi_link_prog_run(struct bpf_kprobe_multi_link *link,
 
 static int
 kprobe_multi_link_handler(struct fprobe *fp, unsigned long fentry_ip,
-			  struct pt_regs *regs, void *data)
+			  unsigned long ret_ip, struct pt_regs *regs,
+			  void *data)
 {
 	struct bpf_kprobe_multi_link *link;
 
@@ -2663,7 +2664,8 @@ kprobe_multi_link_handler(struct fprobe *fp, unsigned long fentry_ip,
 
 static void
 kprobe_multi_link_exit_handler(struct fprobe *fp, unsigned long fentry_ip,
-			       struct pt_regs *regs, void *data)
+			       unsigned long ret_ip, struct pt_regs *regs,
+			       void *data)
 {
 	struct bpf_kprobe_multi_link *link;
 

kernel/trace/fprobe.c

@@ -46,7 +46,7 @@ static inline void __fprobe_handler(unsigned long ip, unsigned long parent_ip,
 	}
 
 	if (fp->entry_handler)
-		ret = fp->entry_handler(fp, ip, ftrace_get_regs(fregs), entry_data);
+		ret = fp->entry_handler(fp, ip, parent_ip, ftrace_get_regs(fregs), entry_data);
 
 	/* If entry_handler returns !0, nmissed is not counted. */
 	if (rh) {
@@ -112,7 +112,7 @@ static void fprobe_kprobe_handler(unsigned long ip, unsigned long parent_ip,
 }
 
 static void fprobe_exit_handler(struct rethook_node *rh, void *data,
-				struct pt_regs *regs)
+				unsigned long ret_ip, struct pt_regs *regs)
 {
 	struct fprobe *fp = (struct fprobe *)data;
 	struct fprobe_rethook_node *fpr;
@@ -133,7 +133,7 @@ static void fprobe_exit_handler(struct rethook_node *rh, void *data,
 		return;
 	}
 
-	fp->exit_handler(fp, fpr->entry_ip, regs,
+	fp->exit_handler(fp, fpr->entry_ip, ret_ip, regs,
 			 fp->entry_data_size ? (void *)fpr->data : NULL);
 	ftrace_test_recursion_unlock(bit);
 }
@@ -348,6 +348,14 @@ 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.
@@ -360,8 +368,7 @@ 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;
 
 	/*

kernel/trace/rethook.c

@@ -301,7 +301,8 @@ unsigned long rethook_trampoline_handler(struct pt_regs *regs,
 			break;
 		handler = READ_ONCE(rhn->rethook->handler);
 		if (handler)
-			handler(rhn, rhn->rethook->data, regs);
+			handler(rhn, rhn->rethook->data,
+				correct_ret_addr, regs);
 
 		if (first == node)
 			break;

kernel/trace/trace.c

@@ -5672,10 +5672,17 @@ 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"
+	"\t           t[:[<group>/][<event>]] <tracepoint> [<args>]\n"
+#endif
 #ifdef CONFIG_HIST_TRIGGERS
 	"\t           s:[synthetic/]<event> <field> [<field>]\n"
 #endif
@@ -5691,7 +5698,11 @@ static const char readme_msg[] =
 	"\t     args: <name>=fetcharg[:type]\n"
 	"\t fetcharg: (%<register>|$<efield>), @<address>, @<symbol>[+|-<offset>],\n"
 #ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
+#ifdef CONFIG_PROBE_EVENTS_BTF_ARGS
+	"\t           $stack<index>, $stack, $retval, $comm, $arg<N>, <argname>\n"
+#else
 	"\t           $stack<index>, $stack, $retval, $comm, $arg<N>,\n"
+#endif
 #else
 	"\t           $stack<index>, $stack, $retval, $comm,\n"
 #endif

kernel/trace/trace.h

@@ -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;

kernel/trace/trace_eprobe.c

@@ -227,37 +227,6 @@ static struct trace_eprobe *alloc_event_probe(const char *group,
 	return ERR_PTR(ret);
 }
 
-static int trace_eprobe_tp_arg_update(struct trace_eprobe *ep, int i)
-{
-	struct probe_arg *parg = &ep->tp.args[i];
-	struct ftrace_event_field *field;
-	struct list_head *head;
-	int ret = -ENOENT;
-
-	head = trace_get_fields(ep->event);
-	list_for_each_entry(field, head, link) {
-		if (!strcmp(parg->code->data, field->name)) {
-			kfree(parg->code->data);
-			parg->code->data = field;
-			return 0;
-		}
-	}
-
-	/*
-	 * Argument not found on event. But allow for comm and COMM
-	 * to be used to get the current->comm.
-	 */
-	if (strcmp(parg->code->data, "COMM") == 0 ||
-	    strcmp(parg->code->data, "comm") == 0) {
-		parg->code->op = FETCH_OP_COMM;
-		ret = 0;
-	}
-
-	kfree(parg->code->data);
-	parg->code->data = NULL;
-	return ret;
-}
-
 static int eprobe_event_define_fields(struct trace_event_call *event_call)
 {
 	struct eprobe_trace_entry_head field;
@@ -817,19 +786,16 @@ find_and_get_event(const char *system, const char *event_name)
 
 static int trace_eprobe_tp_update_arg(struct trace_eprobe *ep, const char *argv[], int i)
 {
-	unsigned int flags = TPARG_FL_KERNEL | TPARG_FL_TPOINT;
+	struct traceprobe_parse_context ctx = {
+		.event = ep->event,
+		.flags = TPARG_FL_KERNEL | TPARG_FL_TEVENT,
+	};
 	int ret;
 
-	ret = traceprobe_parse_probe_arg(&ep->tp, i, argv[i], flags);
+	ret = traceprobe_parse_probe_arg(&ep->tp, i, argv[i], &ctx);
 	if (ret)
 		return ret;
 
-	if (ep->tp.args[i].code->op == FETCH_OP_TP_ARG) {
-		ret = trace_eprobe_tp_arg_update(ep, i);
-		if (ret)
-			trace_probe_log_err(0, BAD_ATTACH_ARG);
-	}
-
 	/* Handle symbols "@" */
 	if (!ret)
 		ret = traceprobe_update_arg(&ep->tp.args[i]);

kernel/trace/trace_kprobe.c

@@ -732,9 +732,10 @@ static int __trace_kprobe_create(int argc, const char *argv[])
 	 *  FETCHARG:TYPE : use TYPE instead of unsigned long.
 	 */
 	struct trace_kprobe *tk = NULL;
-	int i, len, ret = 0;
+	int i, len, new_argc = 0, ret = 0;
 	bool is_return = false;
 	char *symbol = NULL, *tmp = NULL;
+	const char **new_argv = NULL;
 	const char *event = NULL, *group = KPROBE_EVENT_SYSTEM;
 	enum probe_print_type ptype;
 	int maxactive = 0;
@@ -742,7 +743,8 @@ static int __trace_kprobe_create(int argc, const char *argv[])
 	void *addr = NULL;
 	char buf[MAX_EVENT_NAME_LEN];
 	char gbuf[MAX_EVENT_NAME_LEN];
-	unsigned int flags = TPARG_FL_KERNEL;
+	char abuf[MAX_BTF_ARGS_LEN];
+	struct traceprobe_parse_context ctx = { .flags = TPARG_FL_KERNEL };
 
 	switch (argv[0][0]) {
 	case 'r':
@@ -764,7 +766,7 @@ 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)
@@ -823,10 +825,10 @@ static int __trace_kprobe_create(int argc, const char *argv[])
 			goto parse_error;
 		}
 		if (is_return)
-			flags |= TPARG_FL_RETURN;
+			ctx.flags |= TPARG_FL_RETURN;
 		ret = kprobe_on_func_entry(NULL, symbol, offset);
-		if (ret == 0)
-			flags |= TPARG_FL_FENTRY;
+		if (ret == 0 && !is_return)
+			ctx.flags |= TPARG_FL_FENTRY;
 		/* Defer the ENOENT case until register kprobe */
 		if (ret == -EINVAL && is_return) {
 			trace_probe_log_err(0, BAD_RETPROBE);
@@ -854,21 +856,35 @@ static int __trace_kprobe_create(int argc, const char *argv[])
 		event = buf;
 	}
 
+	argc -= 2; argv += 2;
+	ctx.funcname = symbol;
+	new_argv = traceprobe_expand_meta_args(argc, argv, &new_argc,
+					       abuf, MAX_BTF_ARGS_LEN, &ctx);
+	if (IS_ERR(new_argv)) {
+		ret = PTR_ERR(new_argv);
+		new_argv = NULL;
+		goto out;
+	}
+	if (new_argv) {
+		argc = new_argc;
+		argv = new_argv;
+	}
+
 	/* setup a probe */
 	tk = alloc_trace_kprobe(group, event, addr, symbol, offset, maxactive,
-			       argc - 2, is_return);
+				argc, is_return);
 	if (IS_ERR(tk)) {
 		ret = PTR_ERR(tk);
 		/* This must return -ENOMEM, else there is a bug */
 		WARN_ON_ONCE(ret != -ENOMEM);
 		goto out;	/* We know tk 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(&tk->tp, i, argv[i], flags);
+		ctx.offset = 0;
+		ret = traceprobe_parse_probe_arg(&tk->tp, i, argv[i], &ctx);
 		if (ret)
 			goto error;	/* This can be -ENOMEM */
 	}
@@ -892,6 +908,7 @@ static int __trace_kprobe_create(int argc, const char *argv[])
 
 out:
 	trace_probe_log_clear();
+	kfree(new_argv);
 	kfree(symbol);
 	return ret;
 

kernel/trace/trace_probe.h

@@ -23,6 +23,7 @@
 #include <linux/limits.h>
 #include <linux/uaccess.h>
 #include <linux/bitops.h>
+#include <linux/btf.h>
 #include <asm/bitsperlong.h>
 
 #include "trace.h"
@@ -32,7 +33,9 @@
 #define MAX_ARGSTR_LEN		63
 #define MAX_ARRAY_LEN		64
 #define MAX_ARG_NAME_LEN	32
+#define MAX_BTF_ARGS_LEN	128
 #define MAX_STRING_SIZE		PATH_MAX
+#define MAX_ARG_BUF_LEN		(MAX_TRACE_ARGS * MAX_ARG_NAME_LEN)
 
 /* Reserved field names */
 #define FIELD_STRING_IP		"__probe_ip"
@@ -357,15 +360,42 @@ int trace_probe_print_args(struct trace_seq *s, struct probe_arg *args, int nr_a
 #define trace_probe_for_each_link_rcu(pos, tp)	\
 	list_for_each_entry_rcu(pos, &(tp)->event->files, list)
 
+/*
+ * The flags used for parsing trace_probe arguments.
+ * TPARG_FL_RETURN, TPARG_FL_FENTRY and TPARG_FL_TEVENT are mutually exclusive.
+ * TPARG_FL_KERNEL and TPARG_FL_USER are also mutually exclusive.
+ * TPARG_FL_FPROBE and TPARG_FL_TPOINT are optional but it should be with
+ * TPARG_FL_KERNEL.
+ */
 #define TPARG_FL_RETURN BIT(0)
 #define TPARG_FL_KERNEL BIT(1)
 #define TPARG_FL_FENTRY BIT(2)
-#define TPARG_FL_TPOINT BIT(3)
+#define TPARG_FL_TEVENT BIT(3)
 #define TPARG_FL_USER   BIT(4)
-#define TPARG_FL_MASK	GENMASK(4, 0)
+#define TPARG_FL_FPROBE BIT(5)
+#define TPARG_FL_TPOINT BIT(6)
+#define TPARG_FL_LOC_MASK	GENMASK(4, 0)
+
+static inline bool tparg_is_function_entry(unsigned int flags)
+{
+	return (flags & TPARG_FL_LOC_MASK) == (TPARG_FL_KERNEL | TPARG_FL_FENTRY);
+}
+
+struct traceprobe_parse_context {
+	struct trace_event_call *event;
+	const struct btf_param *params;
+	s32 nr_params;
+	const char *funcname;
+	unsigned int flags;
+	int offset;
+};
 
 extern int traceprobe_parse_probe_arg(struct trace_probe *tp, int i,
-				const char *argv, unsigned int flags);
+				      const char *argv,
+				      struct traceprobe_parse_context *ctx);
+const char **traceprobe_expand_meta_args(int argc, const char *argv[],
+					 int *new_argc, char *buf, int bufsize,
+					 struct traceprobe_parse_context *ctx);
 
 extern int traceprobe_update_arg(struct probe_arg *arg);
 extern void traceprobe_free_probe_arg(struct probe_arg *arg);
@@ -404,11 +434,12 @@ 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"),	\
 	C(BAD_RETPROBE,		"Retprobe address must be an function entry"), \
+	C(NO_TRACEPOINT,	"Tracepoint is not found"),		\
 	C(BAD_ADDR_SUFFIX,	"Invalid probed address suffix"), \
 	C(NO_GROUP_NAME,	"Group name is not specified"),		\
 	C(GROUP_TOO_LONG,	"Group name is too long"),		\
@@ -418,6 +449,7 @@ extern int traceprobe_define_arg_fields(struct trace_event_call *event_call,
 	C(BAD_EVENT_NAME,	"Event name must follow the same rules as C identifiers"), \
 	C(EVENT_EXIST,		"Given group/event name is already used by another event"), \
 	C(RETVAL_ON_PROBE,	"$retval is not available on probe"),	\
+	C(NO_RETVAL,		"This function returns 'void' type"),	\
 	C(BAD_STACK_NUM,	"Invalid stack number"),		\
 	C(BAD_ARG_NUM,		"Invalid argument number"),		\
 	C(BAD_VAR,		"Invalid $-valiable specified"),	\
@@ -456,7 +488,14 @@ extern int traceprobe_define_arg_fields(struct trace_event_call *event_call,
 	C(NO_EVENT_INFO,	"This requires both group and event name to attach"),\
 	C(BAD_ATTACH_EVENT,	"Attached event does not exist"),\
 	C(BAD_ATTACH_ARG,	"Attached event does not have this field"),\
-	C(NO_EP_FILTER,		"No filter rule after 'if'"),
+	C(NO_EP_FILTER,		"No filter rule after 'if'"),		\
+	C(NOSUP_BTFARG,		"BTF is not available or not supported"),	\
+	C(NO_BTFARG,		"This variable is not found at this probe point"),\
+	C(NO_BTF_ENTRY,		"No BTF entry for this probe point"),	\
+	C(BAD_VAR_ARGS,		"$arg* must be an independent parameter without name etc."),\
+	C(NOFENTRY_ARGS,	"$arg* can be used only on function entry"),	\
+	C(DOUBLE_ARGS,		"$arg* can be used only once in the parameters"),	\
+	C(ARGS_2LONG,		"$arg* failed because the argument list is too long"),
 
 #undef C
 #define C(a, b)		TP_ERR_##a

kernel/trace/trace_uprobe.c

@@ -686,10 +686,12 @@ static int __trace_uprobe_create(int argc, const char **argv)
 
 	/* parse arguments */
 	for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
+		struct traceprobe_parse_context ctx = {
+			.flags = (is_return ? TPARG_FL_RETURN : 0) | TPARG_FL_USER,
+		};
+
 		trace_probe_log_set_index(i + 2);
-		ret = traceprobe_parse_probe_arg(&tu->tp, i, argv[i],
-					(is_return ? TPARG_FL_RETURN : 0) |
-					TPARG_FL_USER);
+		ret = traceprobe_parse_probe_arg(&tu->tp, i, argv[i], &ctx);
 		if (ret)
 			goto error;
 	}

lib/test_fprobe.c

@@ -39,7 +39,8 @@ static noinline u32 fprobe_selftest_nest_target(u32 value, u32 (*nest)(u32))
 }
 
 static notrace int fp_entry_handler(struct fprobe *fp, unsigned long ip,
-				     struct pt_regs *regs, void *data)
+				    unsigned long ret_ip,
+				    struct pt_regs *regs, void *data)
 {
 	KUNIT_EXPECT_FALSE(current_test, preemptible());
 	/* This can be called on the fprobe_selftest_target and the fprobe_selftest_target2 */
@@ -57,6 +58,7 @@ static notrace int fp_entry_handler(struct fprobe *fp, unsigned long ip,
 }
 
 static notrace void fp_exit_handler(struct fprobe *fp, unsigned long ip,
+				    unsigned long ret_ip,
 				    struct pt_regs *regs, void *data)
 {
 	unsigned long ret = regs_return_value(regs);
@@ -78,14 +80,16 @@ static notrace void fp_exit_handler(struct fprobe *fp, unsigned long ip,
 }
 
 static notrace int nest_entry_handler(struct fprobe *fp, unsigned long ip,
-				     struct pt_regs *regs, void *data)
+				      unsigned long ret_ip,
+				      struct pt_regs *regs, void *data)
 {
 	KUNIT_EXPECT_FALSE(current_test, preemptible());
 	return 0;
 }
 
 static notrace void nest_exit_handler(struct fprobe *fp, unsigned long ip,
-				    struct pt_regs *regs, void *data)
+				      unsigned long ret_ip,
+				      struct pt_regs *regs, void *data)
 {
 	KUNIT_EXPECT_FALSE(current_test, preemptible());
 	KUNIT_EXPECT_EQ(current_test, ip, target_nest_ip);

samples/fprobe/fprobe_example.c

@@ -49,6 +49,7 @@ static void show_backtrace(void)
 }
 
 static int sample_entry_handler(struct fprobe *fp, unsigned long ip,
+				unsigned long ret_ip,
 				struct pt_regs *regs, void *data)
 {
 	if (use_trace)
@@ -65,10 +66,11 @@ static int sample_entry_handler(struct fprobe *fp, unsigned long ip,
 	return 0;
 }
 
-static void sample_exit_handler(struct fprobe *fp, unsigned long ip, struct pt_regs *regs,
+static void sample_exit_handler(struct fprobe *fp, unsigned long ip,
+				unsigned long ret_ip, struct pt_regs *regs,
 				void *data)
 {
-	unsigned long rip = instruction_pointer(regs);
+	unsigned long rip = ret_ip;
 
 	if (use_trace)
 		/*

tools/testing/selftests/ftrace/test.d/dynevent/add_remove_btfarg.tc

+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+# description: Generic dynamic event - add/remove probes with BTF arguments
+# requires: dynamic_events "<argname>":README
+
+KPROBES=
+FPROBES=
+
+if grep -qF "p[:[<group>/][<event>]] <place> [<args>]" README ; then
+  KPROBES=yes
+fi
+if grep -qF "f[:[<group>/][<event>]] <func-name>[%return] [<args>]" README ; then
+  FPROBES=yes
+fi
+
+if [ -z "$KPROBES" -a "$FPROBES" ] ; then
+  exit_unsupported
+fi
+
+echo 0 > events/enable
+echo > dynamic_events
+
+TP=kfree
+
+if [ "$FPROBES" ] ; then
+echo "f:fpevent $TP object" >> dynamic_events
+echo "t:tpevent $TP ptr" >> dynamic_events
+
+grep -q "fpevent.*object=object" dynamic_events
+grep -q "tpevent.*ptr=ptr" dynamic_events
+
+echo > dynamic_events
+
+echo "f:fpevent $TP "'$arg1' >> dynamic_events
+grep -q "fpevent.*object=object" dynamic_events
+echo > dynamic_events
+
+echo "f:fpevent $TP "'$arg*' >> dynamic_events
+echo "t:tpevent $TP "'$arg*' >> dynamic_events
+
+grep -q "fpevent.*object=object" dynamic_events
+grep -q "tpevent.*ptr=ptr" dynamic_events
+! grep -q "tpevent.*_data" dynamic_events
+fi
+
+echo > dynamic_events
+
+if [ "$KPROBES" ] ; then
+echo "p:kpevent $TP object" >> dynamic_events
+grep -q "kpevent.*object=object" dynamic_events
+
+echo > dynamic_events
+
+echo "p:kpevent $TP "'$arg*' >> dynamic_events
+grep -q "kpevent.*object=object" dynamic_events
+fi
+
+clear_trace

tools/testing/selftests/ftrace/test.d/dynevent/add_remove_fprobe.tc

+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+# description: Generic dynamic event - add/remove fprobe events
+# requires: dynamic_events "f[:[<group>/][<event>]] <func-name>[%return] [<args>]":README
+
+echo 0 > events/enable
+echo > dynamic_events
+
+PLACE=$FUNCTION_FORK
+
+echo "f:myevent1 $PLACE" >> dynamic_events
+echo "f:myevent2 $PLACE%return" >> dynamic_events
+
+grep -q myevent1 dynamic_events
+grep -q myevent2 dynamic_events
+test -d events/fprobes/myevent1
+test -d events/fprobes/myevent2
+
+echo "-:myevent2" >> dynamic_events
+
+grep -q myevent1 dynamic_events
+! grep -q myevent2 dynamic_events
+
+echo > dynamic_events
+
+clear_trace

tools/testing/selftests/ftrace/test.d/dynevent/add_remove_tprobe.tc

+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+# description: Generic dynamic event - add/remove tracepoint probe events
+# requires: dynamic_events "t[:[<group>/][<event>]] <tracepoint> [<args>]":README
+
+echo 0 > events/enable
+echo > dynamic_events
+
+TRACEPOINT1=kmem_cache_alloc
+TRACEPOINT2=kmem_cache_free
+
+echo "t:myevent1 $TRACEPOINT1" >> dynamic_events
+echo "t:myevent2 $TRACEPOINT2" >> dynamic_events
+
+grep -q myevent1 dynamic_events
+grep -q myevent2 dynamic_events
+test -d events/tracepoints/myevent1
+test -d events/tracepoints/myevent2
+
+echo "-:myevent2" >> dynamic_events
+
+grep -q myevent1 dynamic_events
+! grep -q myevent2 dynamic_events
+
+echo > dynamic_events
+
+clear_trace

tools/testing/selftests/ftrace/test.d/dynevent/fprobe_syntax_errors.tc

+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+# description: Fprobe event parser error log check
+# requires: dynamic_events "f[:[<group>/][<event>]] <func-name>[%return] [<args>]":README
+
+check_error() { # command-with-error-pos-by-^
+    ftrace_errlog_check 'trace_fprobe' "$1" 'dynamic_events'
+}
+
+case `uname -m` in
+x86_64|i[3456]86)
+  REG=%ax ;;
+aarch64)
+  REG=%x0 ;;
+*)
+  REG=%r0 ;;
+esac
+
+check_error 'f^100 vfs_read'		# MAXACT_NO_KPROBE
+check_error 'f^1a111 vfs_read'		# BAD_MAXACT
+check_error 'f^100000 vfs_read'		# MAXACT_TOO_BIG
+
+check_error 'f ^non_exist_func'		# BAD_PROBE_ADDR (enoent)
+check_error 'f ^vfs_read+10'		# BAD_PROBE_ADDR
+check_error 'f:^/bar vfs_read'		# NO_GROUP_NAME
+check_error 'f:^12345678901234567890123456789012345678901234567890123456789012345/bar vfs_read'	# GROUP_TOO_LONG
+
+check_error 'f:^foo.1/bar vfs_read'	# BAD_GROUP_NAME
+check_error 'f:^ vfs_read'		# NO_EVENT_NAME
+check_error 'f:foo/^12345678901234567890123456789012345678901234567890123456789012345 vfs_read'	# EVENT_TOO_LONG
+check_error 'f:foo/^bar.1 vfs_read'	# BAD_EVENT_NAME
+
+check_error 'f vfs_read ^$retval'	# RETVAL_ON_PROBE
+check_error 'f vfs_read ^$stack10000'	# BAD_STACK_NUM
+
+check_error 'f vfs_read ^$arg10000'	# BAD_ARG_NUM
+
+check_error 'f vfs_read ^$none_var'	# BAD_VAR
+check_error 'f vfs_read ^'$REG		# BAD_VAR
+
+check_error 'f vfs_read ^@12345678abcde'	# BAD_MEM_ADDR
+check_error 'f vfs_read ^@+10'		# FILE_ON_KPROBE
+
+grep -q "imm-value" README && \
+check_error 'f vfs_read arg1=\^x'	# BAD_IMM
+grep -q "imm-string" README && \
+check_error 'f vfs_read arg1=\"abcd^'	# IMMSTR_NO_CLOSE
+
+check_error 'f vfs_read ^+0@0)'		# DEREF_NEED_BRACE
+check_error 'f vfs_read ^+0ab1(@0)'	# BAD_DEREF_OFFS
+check_error 'f vfs_read +0(+0(@0^)'	# DEREF_OPEN_BRACE
+
+if grep -A1 "fetcharg:" README | grep -q '\$comm' ; then
+check_error 'f vfs_read +0(^$comm)'	# COMM_CANT_DEREF
+fi
+
+check_error 'f vfs_read ^&1'		# BAD_FETCH_ARG
+
+
+# We've introduced this limitation with array support
+if grep -q ' <type>\\\[<array-size>\\\]' README; then
+check_error 'f vfs_read +0(^+0(+0(+0(+0(+0(+0(+0(+0(+0(+0(+0(+0(+0(@0))))))))))))))'	# TOO_MANY_OPS?
+check_error 'f vfs_read +0(@11):u8[10^'		# ARRAY_NO_CLOSE
+check_error 'f vfs_read +0(@11):u8[10]^a'	# BAD_ARRAY_SUFFIX
+check_error 'f vfs_read +0(@11):u8[^10a]'	# BAD_ARRAY_NUM
+check_error 'f vfs_read +0(@11):u8[^256]'	# ARRAY_TOO_BIG
+fi
+
+check_error 'f vfs_read @11:^unknown_type'	# BAD_TYPE
+check_error 'f vfs_read $stack0:^string'	# BAD_STRING
+check_error 'f vfs_read @11:^b10@a/16'		# BAD_BITFIELD
+
+check_error 'f vfs_read ^arg123456789012345678901234567890=@11'	# ARG_NAME_TOO_LOG
+check_error 'f vfs_read ^=@11'			# NO_ARG_NAME
+check_error 'f vfs_read ^var.1=@11'		# BAD_ARG_NAME
+check_error 'f vfs_read var1=@11 ^var1=@12'	# USED_ARG_NAME
+check_error 'f vfs_read ^+1234567(+1234567(+1234567(+1234567(+1234567(+1234567(@1234))))))'	# ARG_TOO_LONG
+check_error 'f vfs_read arg1=^'			# NO_ARG_BODY
+
+
+# multiprobe errors
+if grep -q "Create/append/" README && grep -q "imm-value" README; then
+echo "f:fprobes/testevent $FUNCTION_FORK" > dynamic_events
+check_error '^f:fprobes/testevent do_exit%return'	# DIFF_PROBE_TYPE
+
+# Explicitly use printf "%s" to not interpret \1
+printf "%s" "f:fprobes/testevent $FUNCTION_FORK abcd=\\1" > dynamic_events
+check_error "f:fprobes/testevent $FUNCTION_FORK ^bcd=\\1"	# DIFF_ARG_TYPE
+check_error "f:fprobes/testevent $FUNCTION_FORK ^abcd=\\1:u8"	# DIFF_ARG_TYPE
+check_error "f:fprobes/testevent $FUNCTION_FORK ^abcd=\\\"foo\"" # DIFF_ARG_TYPE
+check_error "^f:fprobes/testevent $FUNCTION_FORK abcd=\\1"	# SAME_PROBE
+fi
+
+# %return suffix errors
+check_error 'f vfs_read^%hoge'		# BAD_ADDR_SUFFIX
+
+# BTF arguments errors
+if grep -q "<argname>" README; then
+check_error 'f vfs_read args=^$arg*'		# BAD_VAR_ARGS
+check_error 'f vfs_read +0(^$arg*)'		# BAD_VAR_ARGS
+check_error 'f vfs_read $arg* ^$arg*'		# DOUBLE_ARGS
+check_error 'f vfs_read%return ^$arg*'		# NOFENTRY_ARGS
+check_error 'f vfs_read ^hoge'			# NO_BTFARG
+check_error 'f kfree ^$arg10'			# NO_BTFARG (exceed the number of parameters)
+check_error 'f kfree%return ^$retval'		# NO_RETVAL
+else
+check_error 'f vfs_read ^$arg*'			# NOSUP_BTFARG
+check_error 't kfree ^$arg*'			# NOSUP_BTFARG
+fi
+
+exit 0

tools/testing/selftests/ftrace/test.d/dynevent/tprobe_syntax_errors.tc

+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+# description: Tracepoint probe event parser error log check
+# requires: dynamic_events "t[:[<group>/][<event>]] <tracepoint> [<args>]":README
+
+check_error() { # command-with-error-pos-by-^
+    ftrace_errlog_check 'trace_fprobe' "$1" 'dynamic_events'
+}
+
+check_error 't^100 kfree'		# BAD_MAXACT_TYPE
+
+check_error 't ^non_exist_tracepoint'	# NO_TRACEPOINT
+check_error 't:^/bar kfree'		# NO_GROUP_NAME
+check_error 't:^12345678901234567890123456789012345678901234567890123456789012345/bar kfree'	# GROUP_TOO_LONG
+
+check_error 't:^foo.1/bar kfree'	# BAD_GROUP_NAME
+check_error 't:^ kfree'			# NO_EVENT_NAME
+check_error 't:foo/^12345678901234567890123456789012345678901234567890123456789012345 kfree'	# EVENT_TOO_LONG
+check_error 't:foo/^bar.1 kfree'	# BAD_EVENT_NAME
+
+check_error 't kfree ^$retval'		# RETVAL_ON_PROBE
+check_error 't kfree ^$stack10000'	# BAD_STACK_NUM
+
+check_error 't kfree ^$arg10000'	# BAD_ARG_NUM
+
+check_error 't kfree ^$none_var'	# BAD_VAR
+check_error 't kfree ^%rax'		# BAD_VAR
+
+check_error 't kfree ^@12345678abcde'	# BAD_MEM_ADDR
+check_error 't kfree ^@+10'		# FILE_ON_KPROBE
+
+grep -q "imm-value" README && \
+check_error 't kfree arg1=\^x'	# BAD_IMM
+grep -q "imm-string" README && \
+check_error 't kfree arg1=\"abcd^'	# IMMSTR_NO_CLOSE
+
+check_error 't kfree ^+0@0)'		# DEREF_NEED_BRACE
+check_error 't kfree ^+0ab1(@0)'	# BAD_DEREF_OFFS
+check_error 't kfree +0(+0(@0^)'	# DEREF_OPEN_BRACE
+
+if grep -A1 "fetcharg:" README | grep -q '\$comm' ; then
+check_error 't kfree +0(^$comm)'	# COMM_CANT_DEREF
+fi
+
+check_error 't kfree ^&1'		# BAD_FETCH_ARG
+
+
+# We've introduced this limitation with array support
+if grep -q ' <type>\\\[<array-size>\\\]' README; then
+check_error 't kfree +0(^+0(+0(+0(+0(+0(+0(+0(+0(+0(+0(+0(+0(+0(@0))))))))))))))'	# TOO_MANY_OPS?
+check_error 't kfree +0(@11):u8[10^'		# ARRAY_NO_CLOSE
+check_error 't kfree +0(@11):u8[10]^a'		# BAD_ARRAY_SUFFIX
+check_error 't kfree +0(@11):u8[^10a]'		# BAD_ARRAY_NUM
+check_error 't kfree +0(@11):u8[^256]'		# ARRAY_TOO_BIG
+fi
+
+check_error 't kfree @11:^unknown_type'		# BAD_TYPE
+check_error 't kfree $stack0:^string'		# BAD_STRING
+check_error 't kfree @11:^b10@a/16'		# BAD_BITFIELD
+
+check_error 't kfree ^arg123456789012345678901234567890=@11'	# ARG_NAME_TOO_LOG
+check_error 't kfree ^=@11'			# NO_ARG_NAME
+check_error 't kfree ^var.1=@11'		# BAD_ARG_NAME
+check_error 't kfree var1=@11 ^var1=@12'	# USED_ARG_NAME
+check_error 't kfree ^+1234567(+1234567(+1234567(+1234567(+1234567(+1234567(@1234))))))'	# ARG_TOO_LONG
+check_error 't kfree arg1=^'			# NO_ARG_BODY
+
+
+# multiprobe errors
+if grep -q "Create/append/" README && grep -q "imm-value" README; then
+echo "t:tracepoint/testevent kfree" > dynamic_events
+check_error '^f:tracepoint/testevent kfree'	# DIFF_PROBE_TYPE
+
+# Explicitly use printf "%s" to not interpret \1
+printf "%s" "t:tracepoints/testevent kfree abcd=\\1" > dynamic_events
+check_error "t:tracepoints/testevent kfree ^bcd=\\1"	# DIFF_ARG_TYPE
+check_error "t:tracepoints/testevent kfree ^abcd=\\1:u8"	# DIFF_ARG_TYPE
+check_error "t:tracepoints/testevent kfree ^abcd=\\\"foo\"" # DIFF_ARG_TYPE
+check_error "^t:tracepoints/testevent kfree abcd=\\1"	# SAME_PROBE
+fi
+
+exit 0

tools/testing/selftests/ftrace/test.d/kprobe/kprobe_insn_boundary.tc

+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0-or-later
+# Copyright (C) 2023 Akanksha J N, IBM corporation
+# description: Register multiple kprobe events in a function
+# requires: kprobe_events
+
+for i in `seq 0 255`; do
+  echo p $FUNCTION_FORK+${i} >> kprobe_events || continue
+done
+
+cat kprobe_events >> $testlog
+
+echo 1 > events/kprobes/enable
+( echo "forked" )
+echo 0 > events/kprobes/enable
+echo > kprobe_events
+echo "Waiting for unoptimizing & freeing"
+sleep 5
+echo "Done"

tools/testing/selftests/ftrace/test.d/kprobe/kprobe_syntax_errors.tc

@@ -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
@@ -103,4 +103,18 @@ check_error 'p vfs_read^%hoge'		# BAD_ADDR_SUFFIX
 check_error 'p ^vfs_read+10%return'	# BAD_RETPROBE
 fi
 
+# BTF arguments errors
+if grep -q "<argname>" README; then
+check_error 'p vfs_read args=^$arg*'		# BAD_VAR_ARGS
+check_error 'p vfs_read +0(^$arg*)'		# BAD_VAR_ARGS
+check_error 'p vfs_read $arg* ^$arg*'		# DOUBLE_ARGS
+check_error 'r vfs_read ^$arg*'			# NOFENTRY_ARGS
+check_error 'p vfs_read+8 ^$arg*'		# NOFENTRY_ARGS
+check_error 'p vfs_read ^hoge'			# NO_BTFARG
+check_error 'p kfree ^$arg10'			# NO_BTFARG (exceed the number of parameters)
+check_error 'r kfree ^$retval'			# NO_RETVAL
+else
+check_error 'p vfs_read ^$arg*'			# NOSUP_BTFARG
+fi
+
 exit 0