Tracing updates:

- Addition of multiprobes to kprobe and uprobe events
    Allows for more than one probe attached to the same location
 
  - Addition of adding immediates to probe parameters
 
  - Clean up of the recordmcount.c code. This brings us closer
    to merging recordmcount into objtool, and reuse code.
 
  - Other small clean ups
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Merge tag 'trace-v5.4' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull tracing updates from Steven Rostedt:

 - Addition of multiprobes to kprobe and uprobe events (allows for more
   than one probe attached to the same location)

 - Addition of adding immediates to probe parameters

 - Clean up of the recordmcount.c code. This brings us closer to merging
   recordmcount into objtool, and reuse code.

 - Other small clean ups

* tag 'trace-v5.4' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (33 commits)
  selftests/ftrace: Update kprobe event error testcase
  tracing/probe: Reject exactly same probe event
  tracing/probe: Fix to allow user to enable events on unloaded modules
  selftests/ftrace: Select an existing function in kprobe_eventname test
  tracing/kprobe: Fix NULL pointer access in trace_porbe_unlink()
  tracing: Make sure variable reference alias has correct var_ref_idx
  tracing: Be more clever when dumping hex in __print_hex()
  ftrace: Simplify ftrace hash lookup code in clear_func_from_hash()
  tracing: Add "gfp_t" support in synthetic_events
  tracing: Rename tracing_reset() to tracing_reset_cpu()
  tracing: Document the stack trace algorithm in the comments
  tracing/arm64: Have max stack tracer handle the case of return address after data
  recordmcount: Clarify what cleanup() does
  recordmcount: Remove redundant cleanup() calls
  recordmcount: Kernel style formatting
  recordmcount: Kernel style function signature formatting
  recordmcount: Rewrite error/success handling
  selftests/ftrace: Add syntax error test for multiprobe
  selftests/ftrace: Add syntax error test for immediates
  selftests/ftrace: Add a testcase for kprobe multiprobe event
  ...

Documentation/trace/kprobetrace.rst

@@ -52,6 +52,7 @@ Synopsis of kprobe_events
   $retval	: Fetch return value.(\*2)
   $comm		: Fetch current task comm.
   +|-[u]OFFS(FETCHARG) : Fetch memory at FETCHARG +|- OFFS address.(\*3)(\*4)
+  \IMM		: Store an immediate value to the argument.
   NAME=FETCHARG : Set NAME as the argument name of FETCHARG.
   FETCHARG:TYPE : Set TYPE as the type of FETCHARG. Currently, basic types
 		  (u8/u16/u32/u64/s8/s16/s32/s64), hexadecimal types

Documentation/trace/uprobetracer.rst

@@ -45,6 +45,7 @@ Synopsis of uprobe_tracer
    $retval	: Fetch return value.(\*1)
    $comm	: Fetch current task comm.
    +|-[u]OFFS(FETCHARG) : Fetch memory at FETCHARG +|- OFFS address.(\*2)(\*3)
+   \IMM		: Store an immediate value to the argument.
    NAME=FETCHARG     : Set NAME as the argument name of FETCHARG.
    FETCHARG:TYPE     : Set TYPE as the type of FETCHARG. Currently, basic types
 		       (u8/u16/u32/u64/s8/s16/s32/s64), hexadecimal types

arch/arm64/include/asm/ftrace.h

@@ -14,6 +14,19 @@
 #define MCOUNT_ADDR		((unsigned long)_mcount)
 #define MCOUNT_INSN_SIZE	AARCH64_INSN_SIZE
 
+/*
+ * Currently, gcc tends to save the link register after the local variables
+ * on the stack. This causes the max stack tracer to report the function
+ * frame sizes for the wrong functions. By defining
+ * ARCH_FTRACE_SHIFT_STACK_TRACER, it will tell the stack tracer to expect
+ * to find the return address on the stack after the local variables have
+ * been set up.
+ *
+ * Note, this may change in the future, and we will need to deal with that
+ * if it were to happen.
+ */
+#define ARCH_FTRACE_SHIFT_STACK_TRACER 1
+
 #ifndef __ASSEMBLY__
 #include <linux/compat.h>
 

kernel/kprobes.c

@@ -961,9 +961,16 @@ static struct kprobe *alloc_aggr_kprobe(struct kprobe *p)
 
 #ifdef CONFIG_KPROBES_ON_FTRACE
 static struct ftrace_ops kprobe_ftrace_ops __read_mostly = {
+	.func = kprobe_ftrace_handler,
+	.flags = FTRACE_OPS_FL_SAVE_REGS,
+};
+
+static struct ftrace_ops kprobe_ipmodify_ops __read_mostly = {
 	.func = kprobe_ftrace_handler,
 	.flags = FTRACE_OPS_FL_SAVE_REGS | FTRACE_OPS_FL_IPMODIFY,
 };
+
+static int kprobe_ipmodify_enabled;
 static int kprobe_ftrace_enabled;
 
 /* Must ensure p->addr is really on ftrace */
@@ -976,58 +983,75 @@ static int prepare_kprobe(struct kprobe *p)
 }
 
 /* Caller must lock kprobe_mutex */
-static int arm_kprobe_ftrace(struct kprobe *p)
+static int __arm_kprobe_ftrace(struct kprobe *p, struct ftrace_ops *ops,
+			       int *cnt)
 {
 	int ret = 0;
 
-	ret = ftrace_set_filter_ip(&kprobe_ftrace_ops,
+	ret = ftrace_set_filter_ip(ops, (unsigned long)p->addr, 0, 0);
-				   (unsigned long)p->addr, 0, 0);
 	if (ret) {
 		pr_debug("Failed to arm kprobe-ftrace at %pS (%d)\n",
 			 p->addr, ret);
 		return ret;
 	}
 
-	if (kprobe_ftrace_enabled == 0) {
+	if (*cnt == 0) {
-		ret = register_ftrace_function(&kprobe_ftrace_ops);
+		ret = register_ftrace_function(ops);
 		if (ret) {
 			pr_debug("Failed to init kprobe-ftrace (%d)\n", ret);
 			goto err_ftrace;
 		}
 	}
 
-	kprobe_ftrace_enabled++;
+	(*cnt)++;
 	return ret;
 
 err_ftrace:
 	/*
-	 * Note: Since kprobe_ftrace_ops has IPMODIFY set, and ftrace requires a
+	 * At this point, sinec ops is not registered, we should be sefe from
-	 * non-empty filter_hash for IPMODIFY ops, we're safe from an accidental
+	 * registering empty filter.
-	 * empty filter_hash which would undesirably trace all functions.
 	 */
-	ftrace_set_filter_ip(&kprobe_ftrace_ops, (unsigned long)p->addr, 1, 0);
+	ftrace_set_filter_ip(ops, (unsigned long)p->addr, 1, 0);
 	return ret;
 }
 
+static int arm_kprobe_ftrace(struct kprobe *p)
+{
+	bool ipmodify = (p->post_handler != NULL);
+
+	return __arm_kprobe_ftrace(p,
+		ipmodify ? &kprobe_ipmodify_ops : &kprobe_ftrace_ops,
+		ipmodify ? &kprobe_ipmodify_enabled : &kprobe_ftrace_enabled);
+}
+
 /* Caller must lock kprobe_mutex */
-static int disarm_kprobe_ftrace(struct kprobe *p)
+static int __disarm_kprobe_ftrace(struct kprobe *p, struct ftrace_ops *ops,
+				  int *cnt)
 {
 	int ret = 0;
 
-	if (kprobe_ftrace_enabled == 1) {
+	if (*cnt == 1) {
-		ret = unregister_ftrace_function(&kprobe_ftrace_ops);
+		ret = unregister_ftrace_function(ops);
 		if (WARN(ret < 0, "Failed to unregister kprobe-ftrace (%d)\n", ret))
 			return ret;
 	}
 
-	kprobe_ftrace_enabled--;
+	(*cnt)--;
 
-	ret = ftrace_set_filter_ip(&kprobe_ftrace_ops,
+	ret = ftrace_set_filter_ip(ops, (unsigned long)p->addr, 1, 0);
-			   (unsigned long)p->addr, 1, 0);
 	WARN_ONCE(ret < 0, "Failed to disarm kprobe-ftrace at %pS (%d)\n",
 		  p->addr, ret);
 	return ret;
 }
+
+static int disarm_kprobe_ftrace(struct kprobe *p)
+{
+	bool ipmodify = (p->post_handler != NULL);
+
+	return __disarm_kprobe_ftrace(p,
+		ipmodify ? &kprobe_ipmodify_ops : &kprobe_ftrace_ops,
+		ipmodify ? &kprobe_ipmodify_enabled : &kprobe_ftrace_enabled);
+}
 #else	/* !CONFIG_KPROBES_ON_FTRACE */
 #define prepare_kprobe(p)	arch_prepare_kprobe(p)
 #define arm_kprobe_ftrace(p)	(-ENODEV)

kernel/trace/ftrace.c

@@ -6036,11 +6036,7 @@ clear_func_from_hash(struct ftrace_init_func *func, struct ftrace_hash *hash)
 {
 	struct ftrace_func_entry *entry;
 
-	if (ftrace_hash_empty(hash))
+	entry = ftrace_lookup_ip(hash, func->ip);
-		return;
-
-	entry = __ftrace_lookup_ip(hash, func->ip);
-
 	/*
 	 * Do not allow this rec to match again.
 	 * Yeah, it may waste some memory, but will be removed

kernel/trace/trace.c

@@ -1854,7 +1854,7 @@ int __init register_tracer(struct tracer *type)
 	return ret;
 }
 
-void tracing_reset(struct trace_buffer *buf, int cpu)
+static void tracing_reset_cpu(struct trace_buffer *buf, int cpu)
 {
 	struct ring_buffer *buffer = buf->buffer;
 
@@ -4251,7 +4251,7 @@ static int tracing_open(struct inode *inode, struct file *file)
 		if (cpu == RING_BUFFER_ALL_CPUS)
 			tracing_reset_online_cpus(trace_buf);
 		else
-			tracing_reset(trace_buf, cpu);
+			tracing_reset_cpu(trace_buf, cpu);
 	}
 
 	if (file->f_mode & FMODE_READ) {
@@ -4815,15 +4815,15 @@ static const char readme_msg[] =
 #endif
 #endif /* CONFIG_STACK_TRACER */
 #ifdef CONFIG_DYNAMIC_EVENTS
-	"  dynamic_events\t\t- Add/remove/show the generic dynamic events\n"
+	"  dynamic_events\t\t- Create/append/remove/show the generic dynamic events\n"
 	"\t\t\t  Write into this file to define/undefine new trace events.\n"
 #endif
 #ifdef CONFIG_KPROBE_EVENTS
-	"  kprobe_events\t\t- Add/remove/show the kernel dynamic events\n"
+	"  kprobe_events\t\t- Create/append/remove/show the kernel dynamic events\n"
 	"\t\t\t  Write into this file to define/undefine new trace events.\n"
 #endif
 #ifdef CONFIG_UPROBE_EVENTS
-	"  uprobe_events\t\t- Add/remove/show the userspace dynamic events\n"
+	"  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)
@@ -4848,7 +4848,7 @@ static const char readme_msg[] =
 #else
 	"\t           $stack<index>, $stack, $retval, $comm,\n"
 #endif
-	"\t           +|-[u]<offset>(<fetcharg>)\n"
+	"\t           +|-[u]<offset>(<fetcharg>), \\imm-value, \\\"imm-string\"\n"
 	"\t     type: s8/16/32/64, u8/16/32/64, x8/16/32/64, string, symbol,\n"
 	"\t           b<bit-width>@<bit-offset>/<container-size>, ustring,\n"
 	"\t           <type>\\[<array-size>\\]\n"
@@ -6742,7 +6742,7 @@ tracing_snapshot_write(struct file *filp, const char __user *ubuf, size_t cnt,
 			if (iter->cpu_file == RING_BUFFER_ALL_CPUS)
 				tracing_reset_online_cpus(&tr->max_buffer);
 			else
-				tracing_reset(&tr->max_buffer, iter->cpu_file);
+				tracing_reset_cpu(&tr->max_buffer, iter->cpu_file);
 		}
 		break;
 	}

kernel/trace/trace.h

@@ -677,7 +677,6 @@ trace_buffer_iter(struct trace_iterator *iter, int cpu)
 
 int tracer_init(struct tracer *t, struct trace_array *tr);
 int tracing_is_enabled(void);
-void tracing_reset(struct trace_buffer *buf, int cpu);
 void tracing_reset_online_cpus(struct trace_buffer *buf);
 void tracing_reset_current(int cpu);
 void tracing_reset_all_online_cpus(void);

kernel/trace/trace_dynevent.c

@@ -47,6 +47,7 @@ int dyn_event_release(int argc, char **argv, struct dyn_event_operations *type)
 			return -EINVAL;
 		event++;
 	}
+	argc--; argv++;
 
 	p = strchr(event, '/');
 	if (p) {
@@ -61,10 +62,13 @@ int dyn_event_release(int argc, char **argv, struct dyn_event_operations *type)
 	for_each_dyn_event_safe(pos, n) {
 		if (type && type != pos->ops)
 			continue;
-		if (pos->ops->match(system, event, pos)) {
+		if (!pos->ops->match(system, event,
-			ret = pos->ops->free(pos);
+				argc, (const char **)argv, pos))
+			continue;
+
+		ret = pos->ops->free(pos);
+		if (ret)
 			break;
-		}
 	}
 	mutex_unlock(&event_mutex);
 

kernel/trace/trace_dynevent.h

@@ -31,8 +31,9 @@ struct dyn_event;
  * @is_busy: Check whether given event is busy so that it can not be deleted.
  *  Return true if it is busy, otherwides false.
  * @free: Delete the given event. Return 0 if success, otherwides error.
- * @match: Check whether given event and system name match this event.
+ * @match: Check whether given event and system name match this event. The argc
- *  Return true if it matches, otherwides false.
+ *  and argv is used for exact match. Return true if it matches, otherwides
+ *  false.
  *
  * Except for @create, these methods are called under holding event_mutex.
  */
@@ -43,7 +44,7 @@ struct dyn_event_operations {
 	bool (*is_busy)(struct dyn_event *ev);
 	int (*free)(struct dyn_event *ev);
 	bool (*match)(const char *system, const char *event,
-			struct dyn_event *ev);
+		      int argc, const char **argv, struct dyn_event *ev);
 };
 
 /* Register new dyn_event type -- must be called at first */

kernel/trace/trace_events_hist.c

@@ -13,6 +13,10 @@
 #include <linux/rculist.h>
 #include <linux/tracefs.h>
 
+/* for gfp flag names */
+#include <linux/trace_events.h>
+#include <trace/events/mmflags.h>
+
 #include "tracing_map.h"
 #include "trace.h"
 #include "trace_dynevent.h"
@@ -374,7 +378,7 @@ static int synth_event_show(struct seq_file *m, struct dyn_event *ev);
 static int synth_event_release(struct dyn_event *ev);
 static bool synth_event_is_busy(struct dyn_event *ev);
 static bool synth_event_match(const char *system, const char *event,
-			      struct dyn_event *ev);
+			int argc, const char **argv, struct dyn_event *ev);
 
 static struct dyn_event_operations synth_event_ops = {
 	.create = synth_event_create,
@@ -422,7 +426,7 @@ static bool synth_event_is_busy(struct dyn_event *ev)
 }
 
 static bool synth_event_match(const char *system, const char *event,
-			      struct dyn_event *ev)
+			int argc, const char **argv, struct dyn_event *ev)
 {
 	struct synth_event *sev = to_synth_event(ev);
 
@@ -752,6 +756,8 @@ static int synth_field_size(char *type)
 		size = sizeof(unsigned long);
 	else if (strcmp(type, "pid_t") == 0)
 		size = sizeof(pid_t);
+	else if (strcmp(type, "gfp_t") == 0)
+		size = sizeof(gfp_t);
 	else if (synth_field_is_string(type))
 		size = synth_field_string_size(type);
 
@@ -792,6 +798,8 @@ static const char *synth_field_fmt(char *type)
 		fmt = "%lu";
 	else if (strcmp(type, "pid_t") == 0)
 		fmt = "%d";
+	else if (strcmp(type, "gfp_t") == 0)
+		fmt = "%x";
 	else if (synth_field_is_string(type))
 		fmt = "%s";
 
@@ -834,9 +842,20 @@ static enum print_line_t print_synth_event(struct trace_iterator *iter,
 					 i == se->n_fields - 1 ? "" : " ");
 			n_u64 += STR_VAR_LEN_MAX / sizeof(u64);
 		} else {
+			struct trace_print_flags __flags[] = {
+			    __def_gfpflag_names, {-1, NULL} };
+
 			trace_seq_printf(s, print_fmt, se->fields[i]->name,
 					 entry->fields[n_u64],
 					 i == se->n_fields - 1 ? "" : " ");
+
+			if (strcmp(se->fields[i]->type, "gfp_t") == 0) {
+				trace_seq_puts(s, " (");
+				trace_print_flags_seq(s, "|",
+						      entry->fields[n_u64],
+						      __flags);
+				trace_seq_putc(s, ')');
+			}
 			n_u64++;
 		}
 	}
@@ -2785,6 +2804,8 @@ static struct hist_field *create_alias(struct hist_trigger_data *hist_data,
 		return NULL;
 	}
 
+	alias->var_ref_idx = var_ref->var_ref_idx;
+
 	return alias;
 }
 

kernel/trace/trace_kprobe.c

@@ -39,7 +39,7 @@ static int trace_kprobe_show(struct seq_file *m, struct dyn_event *ev);
 static int trace_kprobe_release(struct dyn_event *ev);
 static bool trace_kprobe_is_busy(struct dyn_event *ev);
 static bool trace_kprobe_match(const char *system, const char *event,
-			       struct dyn_event *ev);
+			int argc, const char **argv, struct dyn_event *ev);
 
 static struct dyn_event_operations trace_kprobe_ops = {
 	.create = trace_kprobe_create,
@@ -137,13 +137,36 @@ static bool trace_kprobe_is_busy(struct dyn_event *ev)
 	return trace_probe_is_enabled(&tk->tp);
 }
 
+static bool trace_kprobe_match_command_head(struct trace_kprobe *tk,
+					    int argc, const char **argv)
+{
+	char buf[MAX_ARGSTR_LEN + 1];
+
+	if (!argc)
+		return true;
+
+	if (!tk->symbol)
+		snprintf(buf, sizeof(buf), "0x%p", tk->rp.kp.addr);
+	else if (tk->rp.kp.offset)
+		snprintf(buf, sizeof(buf), "%s+%u",
+			 trace_kprobe_symbol(tk), tk->rp.kp.offset);
+	else
+		snprintf(buf, sizeof(buf), "%s", trace_kprobe_symbol(tk));
+	if (strcmp(buf, argv[0]))
+		return false;
+	argc--; argv++;
+
+	return trace_probe_match_command_args(&tk->tp, argc, argv);
+}
+
 static bool trace_kprobe_match(const char *system, const char *event,
-			       struct dyn_event *ev)
+			int argc, const char **argv, struct dyn_event *ev)
 {
 	struct trace_kprobe *tk = to_trace_kprobe(ev);
 
 	return strcmp(trace_probe_name(&tk->tp), event) == 0 &&
-	    (!system || strcmp(trace_probe_group_name(&tk->tp), system) == 0);
+	    (!system || strcmp(trace_probe_group_name(&tk->tp), system) == 0) &&
+	    trace_kprobe_match_command_head(tk, argc, argv);
 }
 
 static nokprobe_inline unsigned long trace_kprobe_nhit(struct trace_kprobe *tk)
@@ -180,20 +203,33 @@ unsigned long trace_kprobe_address(struct trace_kprobe *tk)
 	return addr;
 }
 
+static nokprobe_inline struct trace_kprobe *
+trace_kprobe_primary_from_call(struct trace_event_call *call)
+{
+	struct trace_probe *tp;
+
+	tp = trace_probe_primary_from_call(call);
+	if (WARN_ON_ONCE(!tp))
+		return NULL;
+
+	return container_of(tp, struct trace_kprobe, tp);
+}
+
 bool trace_kprobe_on_func_entry(struct trace_event_call *call)
 {
-	struct trace_kprobe *tk = (struct trace_kprobe *)call->data;
+	struct trace_kprobe *tk = trace_kprobe_primary_from_call(call);
 
-	return kprobe_on_func_entry(tk->rp.kp.addr,
+	return tk ? kprobe_on_func_entry(tk->rp.kp.addr,
 			tk->rp.kp.addr ? NULL : tk->rp.kp.symbol_name,
-			tk->rp.kp.addr ? 0 : tk->rp.kp.offset);
+			tk->rp.kp.addr ? 0 : tk->rp.kp.offset) : false;
 }
 
 bool trace_kprobe_error_injectable(struct trace_event_call *call)
 {
-	struct trace_kprobe *tk = (struct trace_kprobe *)call->data;
+	struct trace_kprobe *tk = trace_kprobe_primary_from_call(call);
 
-	return within_error_injection_list(trace_kprobe_address(tk));
+	return tk ? within_error_injection_list(trace_kprobe_address(tk)) :
+	       false;
 }
 
 static int register_kprobe_event(struct trace_kprobe *tk);
@@ -291,32 +327,68 @@ static inline int __enable_trace_kprobe(struct trace_kprobe *tk)
 	return ret;
 }
 
+static void __disable_trace_kprobe(struct trace_probe *tp)
+{
+	struct trace_probe *pos;
+	struct trace_kprobe *tk;
+
+	list_for_each_entry(pos, trace_probe_probe_list(tp), list) {
+		tk = container_of(pos, struct trace_kprobe, tp);
+		if (!trace_kprobe_is_registered(tk))
+			continue;
+		if (trace_kprobe_is_return(tk))
+			disable_kretprobe(&tk->rp);
+		else
+			disable_kprobe(&tk->rp.kp);
+	}
+}
+
 /*
  * Enable trace_probe
  * if the file is NULL, enable "perf" handler, or enable "trace" handler.
  */
-static int
+static int enable_trace_kprobe(struct trace_event_call *call,
-enable_trace_kprobe(struct trace_kprobe *tk, struct trace_event_file *file)
+				struct trace_event_file *file)
 {
-	bool enabled = trace_probe_is_enabled(&tk->tp);
+	struct trace_probe *pos, *tp;
+	struct trace_kprobe *tk;
+	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(&tk->tp, file);
+		ret = trace_probe_add_file(tp, file);
 		if (ret)
 			return ret;
 	} else
-		trace_probe_set_flag(&tk->tp, TP_FLAG_PROFILE);
+		trace_probe_set_flag(tp, TP_FLAG_PROFILE);
 
 	if (enabled)
 		return 0;
 
-	ret = __enable_trace_kprobe(tk);
+	list_for_each_entry(pos, trace_probe_probe_list(tp), list) {
+		tk = container_of(pos, struct trace_kprobe, tp);
+		if (trace_kprobe_has_gone(tk))
+			continue;
+		ret = __enable_trace_kprobe(tk);
+		if (ret)
+			break;
+		enabled = true;
+	}
+
 	if (ret) {
+		/* Failed to enable one of them. Roll back all */
+		if (enabled)
+			__disable_trace_kprobe(tp);
 		if (file)
-			trace_probe_remove_file(&tk->tp, file);
+			trace_probe_remove_file(tp, file);
 		else
-			trace_probe_clear_flag(&tk->tp, TP_FLAG_PROFILE);
+			trace_probe_clear_flag(tp, TP_FLAG_PROFILE);
 	}
 
 	return ret;
@@ -326,11 +398,14 @@ enable_trace_kprobe(struct trace_kprobe *tk, struct trace_event_file *file)
  * Disable trace_probe
  * if the file is NULL, disable "perf" handler, or disable "trace" handler.
  */
-static int
+static int disable_trace_kprobe(struct trace_event_call *call,
-disable_trace_kprobe(struct trace_kprobe *tk, struct trace_event_file *file)
+				struct trace_event_file *file)
 {
-	struct trace_probe *tp = &tk->tp;
+	struct trace_probe *tp;
-	int ret = 0;
+
+	tp = trace_probe_primary_from_call(call);
+	if (WARN_ON_ONCE(!tp))
+		return -ENODEV;
 
 	if (file) {
 		if (!trace_probe_get_file_link(tp, file))
@@ -341,12 +416,8 @@ disable_trace_kprobe(struct trace_kprobe *tk, struct trace_event_file *file)
 	} else
 		trace_probe_clear_flag(tp, TP_FLAG_PROFILE);
 
-	if (!trace_probe_is_enabled(tp) && trace_kprobe_is_registered(tk)) {
+	if (!trace_probe_is_enabled(tp))
-		if (trace_kprobe_is_return(tk))
+		__disable_trace_kprobe(tp);
-			disable_kretprobe(&tk->rp);
-		else
-			disable_kprobe(&tk->rp.kp);
-	}
 
  out:
 	if (file)
@@ -358,7 +429,7 @@ disable_trace_kprobe(struct trace_kprobe *tk, struct trace_event_file *file)
 		 */
 		trace_probe_remove_file(tp, file);
 
-	return ret;
+	return 0;
 }
 
 #if defined(CONFIG_KPROBES_ON_FTRACE) && \
@@ -437,6 +508,10 @@ static void __unregister_trace_kprobe(struct trace_kprobe *tk)
 /* Unregister a trace_probe and probe_event */
 static int unregister_trace_kprobe(struct trace_kprobe *tk)
 {
+	/* If other probes are on the event, just unregister kprobe */
+	if (trace_probe_has_sibling(&tk->tp))
+		goto unreg;
+
 	/* Enabled event can not be unregistered */
 	if (trace_probe_is_enabled(&tk->tp))
 		return -EBUSY;
@@ -445,12 +520,81 @@ static int unregister_trace_kprobe(struct trace_kprobe *tk)
 	if (unregister_kprobe_event(tk))
 		return -EBUSY;
 
+unreg:
 	__unregister_trace_kprobe(tk);
 	dyn_event_remove(&tk->devent);
+	trace_probe_unlink(&tk->tp);
 
 	return 0;
 }
 
+static bool trace_kprobe_has_same_kprobe(struct trace_kprobe *orig,
+					 struct trace_kprobe *comp)
+{
+	struct trace_probe_event *tpe = orig->tp.event;
+	struct trace_probe *pos;
+	int i;
+
+	list_for_each_entry(pos, &tpe->probes, list) {
+		orig = container_of(pos, struct trace_kprobe, tp);
+		if (strcmp(trace_kprobe_symbol(orig),
+			   trace_kprobe_symbol(comp)) ||
+		    trace_kprobe_offset(orig) != trace_kprobe_offset(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))
+				continue;
+		}
+
+		return true;
+	}
+
+	return false;
+}
+
+static int append_trace_kprobe(struct trace_kprobe *tk, struct trace_kprobe *to)
+{
+	int ret;
+
+	ret = trace_probe_compare_arg_type(&tk->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_kprobe_has_same_kprobe(to, tk)) {
+		trace_probe_log_set_index(0);
+		trace_probe_log_err(0, SAME_PROBE);
+		return -EEXIST;
+	}
+
+	/* Append to existing event */
+	ret = trace_probe_append(&tk->tp, &to->tp);
+	if (ret)
+		return ret;
+
+	/* Register k*probe */
+	ret = __register_trace_kprobe(tk);
+	if (ret == -ENOENT && !trace_kprobe_module_exist(tk)) {
+		pr_warn("This probe might be able to register after target module is loaded. Continue.\n");
+		ret = 0;
+	}
+
+	if (ret)
+		trace_probe_unlink(&tk->tp);
+	else
+		dyn_event_add(&tk->devent);
+
+	return ret;
+}
+
 /* Register a trace_probe and probe_event */
 static int register_trace_kprobe(struct trace_kprobe *tk)
 {
@@ -459,14 +603,17 @@ static int register_trace_kprobe(struct trace_kprobe *tk)
 
 	mutex_lock(&event_mutex);
 
-	/* Delete old (same name) event if exist */
 	old_tk = find_trace_kprobe(trace_probe_name(&tk->tp),
 				   trace_probe_group_name(&tk->tp));
 	if (old_tk) {
-		ret = unregister_trace_kprobe(old_tk);
+		if (trace_kprobe_is_return(tk) != trace_kprobe_is_return(old_tk)) {
-		if (ret < 0)
+			trace_probe_log_set_index(0);
-			goto end;
+			trace_probe_log_err(0, DIFF_PROBE_TYPE);
-		free_trace_kprobe(old_tk);
+			ret = -EEXIST;
+		} else {
+			ret = append_trace_kprobe(tk, old_tk);
+		}
+		goto end;
 	}
 
 	/* Register new event */
@@ -700,7 +847,7 @@ static int trace_kprobe_create(int argc, const char *argv[])
 			trace_probe_log_err(0, BAD_INSN_BNDRY);
 		else if (ret == -ENOENT)
 			trace_probe_log_err(0, BAD_PROBE_ADDR);
-		else if (ret != -ENOMEM)
+		else if (ret != -ENOMEM && ret != -EEXIST)
 			trace_probe_log_err(0, FAIL_REG_PROBE);
 		goto error;
 	}
@@ -965,6 +1112,9 @@ retry:
 	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);
@@ -1089,7 +1239,10 @@ print_kprobe_event(struct trace_iterator *iter, int flags,
 	struct trace_probe *tp;
 
 	field = (struct kprobe_trace_entry_head *)iter->ent;
-	tp = container_of(event, struct trace_probe, call.event);
+	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));
 
@@ -1116,7 +1269,10 @@ print_kretprobe_event(struct trace_iterator *iter, int flags,
 	struct trace_probe *tp;
 
 	field = (struct kretprobe_trace_entry_head *)iter->ent;
-	tp = container_of(event, struct trace_probe, call.event);
+	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));
 
@@ -1145,23 +1301,31 @@ static int kprobe_event_define_fields(struct trace_event_call *event_call)
 {
 	int ret;
 	struct kprobe_trace_entry_head field;
-	struct trace_kprobe *tk = (struct trace_kprobe *)event_call->data;
+	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), &tk->tp);
+	return traceprobe_define_arg_fields(event_call, sizeof(field), tp);
 }
 
 static int kretprobe_event_define_fields(struct trace_event_call *event_call)
 {
 	int ret;
 	struct kretprobe_trace_entry_head field;
-	struct trace_kprobe *tk = (struct trace_kprobe *)event_call->data;
+	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), &tk->tp);
+	return traceprobe_define_arg_fields(event_call, sizeof(field), tp);
 }
 
 #ifdef CONFIG_PERF_EVENTS
@@ -1289,20 +1453,19 @@ int bpf_get_kprobe_info(const struct perf_event *event, u32 *fd_type,
 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);
+		return enable_trace_kprobe(event, file);
 	case TRACE_REG_UNREGISTER:
-		return disable_trace_kprobe(tk, file);
+		return disable_trace_kprobe(event, file);
 
 #ifdef CONFIG_PERF_EVENTS
 	case TRACE_REG_PERF_REGISTER:
-		return enable_trace_kprobe(tk, NULL);
+		return enable_trace_kprobe(event, NULL);
 	case TRACE_REG_PERF_UNREGISTER:
-		return disable_trace_kprobe(tk, NULL);
+		return disable_trace_kprobe(event, NULL);
 	case TRACE_REG_PERF_OPEN:
 	case TRACE_REG_PERF_CLOSE:
 	case TRACE_REG_PERF_ADD:
@@ -1369,7 +1532,6 @@ static inline void init_trace_event_call(struct trace_kprobe *tk)
 
 	call->flags = TRACE_EVENT_FL_KPROBE;
 	call->class->reg = kprobe_register;
-	call->data = tk;
 }
 
 static int register_kprobe_event(struct trace_kprobe *tk)
@@ -1432,7 +1594,9 @@ 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);
+	tk = trace_kprobe_primary_from_call(event_call);
+	if (unlikely(!tk))
+		return;
 
 	if (trace_probe_is_enabled(&tk->tp)) {
 		WARN_ON(1);
@@ -1577,7 +1741,8 @@ static __init int kprobe_trace_self_tests_init(void)
 				pr_warn("error on getting probe file.\n");
 				warn++;
 			} else
-				enable_trace_kprobe(tk, file);
+				enable_trace_kprobe(
+					trace_probe_event_call(&tk->tp), file);
 		}
 	}
 
@@ -1598,7 +1763,8 @@ static __init int kprobe_trace_self_tests_init(void)
 				pr_warn("error on getting probe file.\n");
 				warn++;
 			} else
-				enable_trace_kprobe(tk, file);
+				enable_trace_kprobe(
+					trace_probe_event_call(&tk->tp), file);
 		}
 	}
 
@@ -1631,7 +1797,8 @@ static __init int kprobe_trace_self_tests_init(void)
 			pr_warn("error on getting probe file.\n");
 			warn++;
 		} else
-			disable_trace_kprobe(tk, file);
+			disable_trace_kprobe(
+				trace_probe_event_call(&tk->tp), file);
 	}
 
 	tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
@@ -1649,7 +1816,8 @@ static __init int kprobe_trace_self_tests_init(void)
 			pr_warn("error on getting probe file.\n");
 			warn++;
 		} else
-			disable_trace_kprobe(tk, file);
+			disable_trace_kprobe(
+				trace_probe_event_call(&tk->tp), file);
 	}
 
 	ret = trace_run_command("-:testprobe", create_or_delete_trace_kprobe);

kernel/trace/trace_output.c

@@ -219,10 +219,10 @@ trace_print_hex_seq(struct trace_seq *p, const unsigned char *buf, int buf_len,
 {
 	int i;
 	const char *ret = trace_seq_buffer_ptr(p);
+	const char *fmt = concatenate ? "%*phN" : "%*ph";
 
-	for (i = 0; i < buf_len; i++)
+	for (i = 0; i < buf_len; i += 16)
-		trace_seq_printf(p, "%s%2.2x", concatenate || i == 0 ? "" : " ",
+		trace_seq_printf(p, fmt, min(buf_len - i, 16), &buf[i]);
-				 buf[i]);
 	trace_seq_putc(p, 0);
 
 	return ret;

kernel/trace/trace_probe.c

@@ -316,6 +316,29 @@ inval_var:
 	return -EINVAL;
 }
 
+static int str_to_immediate(char *str, unsigned long *imm)
+{
+	if (isdigit(str[0]))
+		return kstrtoul(str, 0, imm);
+	else if (str[0] == '-')
+		return kstrtol(str, 0, (long *)imm);
+	else if (str[0] == '+')
+		return kstrtol(str + 1, 0, (long *)imm);
+	return -EINVAL;
+}
+
+static int __parse_imm_string(char *str, char **pbuf, int offs)
+{
+	size_t len = strlen(str);
+
+	if (str[len - 1] != '"') {
+		trace_probe_log_err(offs + len, IMMSTR_NO_CLOSE);
+		return -EINVAL;
+	}
+	*pbuf = kstrndup(str, len - 1, GFP_KERNEL);
+	return 0;
+}
+
 /* Recursive argument parser */
 static int
 parse_probe_arg(char *arg, const struct fetch_type *type,
@@ -430,7 +453,8 @@ parse_probe_arg(char *arg, const struct fetch_type *type,
 			ret = parse_probe_arg(arg, t2, &code, end, flags, offs);
 			if (ret)
 				break;
-			if (code->op == FETCH_OP_COMM) {
+			if (code->op == FETCH_OP_COMM ||
+			    code->op == FETCH_OP_DATA) {
 				trace_probe_log_err(offs, COMM_CANT_DEREF);
 				return -EINVAL;
 			}
@@ -444,6 +468,21 @@ parse_probe_arg(char *arg, const struct fetch_type *type,
 			code->offset = offset;
 		}
 		break;
+	case '\\':	/* Immediate value */
+		if (arg[1] == '"') {	/* Immediate string */
+			ret = __parse_imm_string(arg + 2, &tmp, offs + 2);
+			if (ret)
+				break;
+			code->op = FETCH_OP_DATA;
+			code->data = tmp;
+		} else {
+			ret = str_to_immediate(arg + 1, &code->immediate);
+			if (ret)
+				trace_probe_log_err(offs + 1, BAD_IMM);
+			else
+				code->op = FETCH_OP_IMM;
+		}
+		break;
 	}
 	if (!ret && code->op == FETCH_OP_NOP) {
 		/* Parsed, but do not find fetch method */
@@ -542,8 +581,11 @@ static int traceprobe_parse_probe_arg_body(char *arg, ssize_t *size,
 		}
 	}
 
-	/* Since $comm can not be dereferred, we can find $comm by strcmp */
+	/*
-	if (strcmp(arg, "$comm") == 0) {
+	 * Since $comm and immediate string can not be dereferred,
+	 * we can find those by strcmp.
+	 */
+	if (strcmp(arg, "$comm") == 0 || strncmp(arg, "\\\"", 2) == 0) {
 		/* The type of $comm must be "string", and not an array. */
 		if (parg->count || (t && strcmp(t, "string")))
 			return -EINVAL;
@@ -580,7 +622,8 @@ static int traceprobe_parse_probe_arg_body(char *arg, ssize_t *size,
 	if (!strcmp(parg->type->name, "string") ||
 	    !strcmp(parg->type->name, "ustring")) {
 		if (code->op != FETCH_OP_DEREF && code->op != FETCH_OP_UDEREF &&
-		    code->op != FETCH_OP_IMM && code->op != FETCH_OP_COMM) {
+		    code->op != FETCH_OP_IMM && code->op != FETCH_OP_COMM &&
+		    code->op != FETCH_OP_DATA) {
 			trace_probe_log_err(offset + (t ? (t - arg) : 0),
 					    BAD_STRING);
 			ret = -EINVAL;
@@ -589,9 +632,10 @@ static int traceprobe_parse_probe_arg_body(char *arg, ssize_t *size,
 		if ((code->op == FETCH_OP_IMM || code->op == FETCH_OP_COMM) ||
 		     parg->count) {
 			/*
-			 * IMM and COMM is pointing actual address, those must
+			 * IMM, DATA and COMM is pointing actual address, those
-			 * be kept, and if parg->count != 0, this is an array
+			 * must be kept, and if parg->count != 0, this is an
-			 * of string pointers instead of string address itself.
+			 * array of string pointers instead of string address
+			 * itself.
 			 */
 			code++;
 			if (code->op != FETCH_OP_NOP) {
@@ -665,7 +709,8 @@ static int traceprobe_parse_probe_arg_body(char *arg, ssize_t *size,
 fail:
 	if (ret) {
 		for (code = tmp; code < tmp + FETCH_INSN_MAX; code++)
-			if (code->op == FETCH_NOP_SYMBOL)
+			if (code->op == FETCH_NOP_SYMBOL ||
+			    code->op == FETCH_OP_DATA)
 				kfree(code->data);
 	}
 	kfree(tmp);
@@ -736,7 +781,8 @@ void traceprobe_free_probe_arg(struct probe_arg *arg)
 	struct fetch_insn *code = arg->code;
 
 	while (code && code->op != FETCH_OP_END) {
-		if (code->op == FETCH_NOP_SYMBOL)
+		if (code->op == FETCH_NOP_SYMBOL ||
+		    code->op == FETCH_OP_DATA)
 			kfree(code->data);
 		code++;
 	}
@@ -886,44 +932,85 @@ int traceprobe_define_arg_fields(struct trace_event_call *event_call,
 	return 0;
 }
 
+static void trace_probe_event_free(struct trace_probe_event *tpe)
+{
+	kfree(tpe->class.system);
+	kfree(tpe->call.name);
+	kfree(tpe->call.print_fmt);
+	kfree(tpe);
+}
+
+int trace_probe_append(struct trace_probe *tp, struct trace_probe *to)
+{
+	if (trace_probe_has_sibling(tp))
+		return -EBUSY;
+
+	list_del_init(&tp->list);
+	trace_probe_event_free(tp->event);
+
+	tp->event = to->event;
+	list_add_tail(&tp->list, trace_probe_probe_list(to));
+
+	return 0;
+}
+
+void trace_probe_unlink(struct trace_probe *tp)
+{
+	list_del_init(&tp->list);
+	if (list_empty(trace_probe_probe_list(tp)))
+		trace_probe_event_free(tp->event);
+	tp->event = NULL;
+}
 
 void trace_probe_cleanup(struct trace_probe *tp)
 {
-	struct trace_event_call *call = trace_probe_event_call(tp);
 	int i;
 
 	for (i = 0; i < tp->nr_args; i++)
 		traceprobe_free_probe_arg(&tp->args[i]);
 
-	if (call->class)
+	if (tp->event)
-		kfree(call->class->system);
+		trace_probe_unlink(tp);
-	kfree(call->name);
-	kfree(call->print_fmt);
 }
 
 int trace_probe_init(struct trace_probe *tp, const char *event,
 		     const char *group)
 {
-	struct trace_event_call *call = trace_probe_event_call(tp);
+	struct trace_event_call *call;
+	int ret = 0;
 
 	if (!event || !group)
 		return -EINVAL;
 
-	call->class = &tp->class;
+	tp->event = kzalloc(sizeof(struct trace_probe_event), GFP_KERNEL);
-	call->name = kstrdup(event, GFP_KERNEL);
+	if (!tp->event)
-	if (!call->name)
 		return -ENOMEM;
 
-	tp->class.system = kstrdup(group, GFP_KERNEL);
+	INIT_LIST_HEAD(&tp->event->files);
-	if (!tp->class.system) {
+	INIT_LIST_HEAD(&tp->event->class.fields);
-		kfree(call->name);
+	INIT_LIST_HEAD(&tp->event->probes);
-		call->name = NULL;
+	INIT_LIST_HEAD(&tp->list);
-		return -ENOMEM;
+	list_add(&tp->event->probes, &tp->list);
+
+	call = trace_probe_event_call(tp);
+	call->class = &tp->event->class;
+	call->name = kstrdup(event, GFP_KERNEL);
+	if (!call->name) {
+		ret = -ENOMEM;
+		goto error;
+	}
+
+	tp->event->class.system = kstrdup(group, GFP_KERNEL);
+	if (!tp->event->class.system) {
+		ret = -ENOMEM;
+		goto error;
 	}
-	INIT_LIST_HEAD(&tp->files);
-	INIT_LIST_HEAD(&tp->class.fields);
 
 	return 0;
+
+error:
+	trace_probe_cleanup(tp);
+	return ret;
 }
 
 int trace_probe_register_event_call(struct trace_probe *tp)
@@ -952,7 +1039,7 @@ int trace_probe_add_file(struct trace_probe *tp, struct trace_event_file *file)
 
 	link->file = file;
 	INIT_LIST_HEAD(&link->list);
-	list_add_tail_rcu(&link->list, &tp->files);
+	list_add_tail_rcu(&link->list, &tp->event->files);
 	trace_probe_set_flag(tp, TP_FLAG_TRACE);
 	return 0;
 }
@@ -983,8 +1070,45 @@ int trace_probe_remove_file(struct trace_probe *tp,
 	synchronize_rcu();
 	kfree(link);
 
-	if (list_empty(&tp->files))
+	if (list_empty(&tp->event->files))
 		trace_probe_clear_flag(tp, TP_FLAG_TRACE);
 
 	return 0;
 }
+
+/*
+ * Return the smallest index of different type argument (start from 1).
+ * If all argument types and name are same, return 0.
+ */
+int trace_probe_compare_arg_type(struct trace_probe *a, struct trace_probe *b)
+{
+	int i;
+
+	for (i = 0; i < a->nr_args; i++) {
+		if ((b->nr_args <= i) ||
+		    ((a->args[i].type != b->args[i].type) ||
+		     (a->args[i].count != b->args[i].count) ||
+		     strcmp(a->args[i].name, b->args[i].name)))
+			return i + 1;
+	}
+
+	return 0;
+}
+
+bool trace_probe_match_command_args(struct trace_probe *tp,
+				    int argc, const char **argv)
+{
+	char buf[MAX_ARGSTR_LEN + 1];
+	int i;
+
+	if (tp->nr_args < argc)
+		return false;
+
+	for (i = 0; i < argc; i++) {
+		snprintf(buf, sizeof(buf), "%s=%s",
+			 tp->args[i].name, tp->args[i].comm);
+		if (strcmp(buf, argv[i]))
+			return false;
+	}
+	return true;
+}

kernel/trace/trace_probe.h

@@ -89,6 +89,7 @@ enum fetch_op {
 	FETCH_OP_COMM,		/* Current comm */
 	FETCH_OP_ARG,		/* Function argument : .param */
 	FETCH_OP_FOFFS,		/* File offset: .immediate */
+	FETCH_OP_DATA,		/* Allocated data: .data */
 	// Stage 2 (dereference) op
 	FETCH_OP_DEREF,		/* Dereference: .offset */
 	FETCH_OP_UDEREF,	/* User-space Dereference: .offset */
@@ -222,11 +223,18 @@ struct probe_arg {
 	const struct fetch_type	*type;	/* Type of this argument */
 };
 
-struct trace_probe {
+/* Event call and class holder */
+struct trace_probe_event {
 	unsigned int			flags;	/* For TP_FLAG_* */
 	struct trace_event_class	class;
 	struct trace_event_call		call;
 	struct list_head 		files;
+	struct list_head		probes;
+};
+
+struct trace_probe {
+	struct list_head		list;
+	struct trace_probe_event	*event;
 	ssize_t				size;	/* trace entry size */
 	unsigned int			nr_args;
 	struct probe_arg		args[];
@@ -240,19 +248,19 @@ struct event_file_link {
 static inline bool trace_probe_test_flag(struct trace_probe *tp,
 					 unsigned int flag)
 {
-	return !!(tp->flags & flag);
+	return !!(tp->event->flags & flag);
 }
 
 static inline void trace_probe_set_flag(struct trace_probe *tp,
 					unsigned int flag)
 {
-	tp->flags |= flag;
+	tp->event->flags |= flag;
 }
 
 static inline void trace_probe_clear_flag(struct trace_probe *tp,
 					  unsigned int flag)
 {
-	tp->flags &= ~flag;
+	tp->event->flags &= ~flag;
 }
 
 static inline bool trace_probe_is_enabled(struct trace_probe *tp)
@@ -262,45 +270,76 @@ static inline bool trace_probe_is_enabled(struct trace_probe *tp)
 
 static inline const char *trace_probe_name(struct trace_probe *tp)
 {
-	return trace_event_name(&tp->call);
+	return trace_event_name(&tp->event->call);
 }
 
 static inline const char *trace_probe_group_name(struct trace_probe *tp)
 {
-	return tp->call.class->system;
+	return tp->event->call.class->system;
 }
 
 static inline struct trace_event_call *
 	trace_probe_event_call(struct trace_probe *tp)
 {
-	return &tp->call;
+	return &tp->event->call;
+}
+
+static inline struct trace_probe_event *
+trace_probe_event_from_call(struct trace_event_call *event_call)
+{
+	return container_of(event_call, struct trace_probe_event, call);
+}
+
+static inline struct trace_probe *
+trace_probe_primary_from_call(struct trace_event_call *call)
+{
+	struct trace_probe_event *tpe = trace_probe_event_from_call(call);
+
+	return list_first_entry(&tpe->probes, struct trace_probe, list);
+}
+
+static inline struct list_head *trace_probe_probe_list(struct trace_probe *tp)
+{
+	return &tp->event->probes;
+}
+
+static inline bool trace_probe_has_sibling(struct trace_probe *tp)
+{
+	struct list_head *list = trace_probe_probe_list(tp);
+
+	return !list_empty(list) && !list_is_singular(list);
 }
 
 static inline int trace_probe_unregister_event_call(struct trace_probe *tp)
 {
 	/* tp->event is unregistered in trace_remove_event_call() */
-	return trace_remove_event_call(&tp->call);
+	return trace_remove_event_call(&tp->event->call);
 }
 
 static inline bool trace_probe_has_single_file(struct trace_probe *tp)
 {
-	return !!list_is_singular(&tp->files);
+	return !!list_is_singular(&tp->event->files);
 }
 
 int trace_probe_init(struct trace_probe *tp, const char *event,
 		     const char *group);
 void trace_probe_cleanup(struct trace_probe *tp);
+int trace_probe_append(struct trace_probe *tp, struct trace_probe *to);
+void trace_probe_unlink(struct trace_probe *tp);
 int trace_probe_register_event_call(struct trace_probe *tp);
 int trace_probe_add_file(struct trace_probe *tp, struct trace_event_file *file);
 int trace_probe_remove_file(struct trace_probe *tp,
 			    struct trace_event_file *file);
 struct event_file_link *trace_probe_get_file_link(struct trace_probe *tp,
 						struct trace_event_file *file);
+int trace_probe_compare_arg_type(struct trace_probe *a, struct trace_probe *b);
+bool trace_probe_match_command_args(struct trace_probe *tp,
+				    int argc, const char **argv);
 
 #define trace_probe_for_each_link(pos, tp)	\
-	list_for_each_entry(pos, &(tp)->files, list)
+	list_for_each_entry(pos, &(tp)->event->files, list)
 #define trace_probe_for_each_link_rcu(pos, tp)	\
-	list_for_each_entry_rcu(pos, &(tp)->files, list)
+	list_for_each_entry_rcu(pos, &(tp)->event->files, list)
 
 /* Check the name is good for event/group/fields */
 static inline bool is_good_name(const char *name)
@@ -370,6 +409,8 @@ extern int traceprobe_define_arg_fields(struct trace_event_call *event_call,
 	C(BAD_VAR,		"Invalid $-valiable specified"),	\
 	C(BAD_REG_NAME,		"Invalid register name"),		\
 	C(BAD_MEM_ADDR,		"Invalid memory address"),		\
+	C(BAD_IMM,		"Invalid immediate value"),		\
+	C(IMMSTR_NO_CLOSE,	"String is not closed with '\"'"),	\
 	C(FILE_ON_KPROBE,	"File offset is not available with kprobe"), \
 	C(BAD_FILE_OFFS,	"Invalid file offset value"),		\
 	C(SYM_ON_UPROBE,	"Symbol is not available with uprobe"),	\
@@ -393,7 +434,10 @@ extern int traceprobe_define_arg_fields(struct trace_event_call *event_call,
 	C(ARG_TOO_LONG,		"Argument expression is too long"),	\
 	C(NO_ARG_BODY,		"No argument expression"),		\
 	C(BAD_INSN_BNDRY,	"Probe point is not an instruction boundary"),\
-	C(FAIL_REG_PROBE,	"Failed to register probe event"),
+	C(FAIL_REG_PROBE,	"Failed to register probe event"),\
+	C(DIFF_PROBE_TYPE,	"Probe type is different from existing probe"),\
+	C(DIFF_ARG_TYPE,	"Argument type or name is different from existing probe"),\
+	C(SAME_PROBE,		"There is already the exact same probe event"),
 
 #undef C
 #define C(a, b)		TP_ERR_##a

kernel/trace/trace_stack.c

@@ -53,6 +53,104 @@ static void print_max_stack(void)
 	}
 }
 
+/*
+ * The stack tracer looks for a maximum stack at each call from a function. It
+ * registers a callback from ftrace, and in that callback it examines the stack
+ * size. It determines the stack size from the variable passed in, which is the
+ * address of a local variable in the stack_trace_call() callback function.
+ * The stack size is calculated by the address of the local variable to the top
+ * of the current stack. If that size is smaller than the currently saved max
+ * stack size, nothing more is done.
+ *
+ * If the size of the stack is greater than the maximum recorded size, then the
+ * following algorithm takes place.
+ *
+ * For architectures (like x86) that store the function's return address before
+ * saving the function's local variables, the stack will look something like
+ * this:
+ *
+ *   [ top of stack ]
+ *    0: sys call entry frame
+ *   10: return addr to entry code
+ *   11: start of sys_foo frame
+ *   20: return addr to sys_foo
+ *   21: start of kernel_func_bar frame
+ *   30: return addr to kernel_func_bar
+ *   31: [ do trace stack here ]
+ *
+ * The save_stack_trace() is called returning all the functions it finds in the
+ * current stack. Which would be (from the bottom of the stack to the top):
+ *
+ *   return addr to kernel_func_bar
+ *   return addr to sys_foo
+ *   return addr to entry code
+ *
+ * Now to figure out how much each of these functions' local variable size is,
+ * a search of the stack is made to find these values. When a match is made, it
+ * is added to the stack_dump_trace[] array. The offset into the stack is saved
+ * in the stack_trace_index[] array. The above example would show:
+ *
+ *        stack_dump_trace[]        |   stack_trace_index[]
+ *        ------------------        +   -------------------
+ *  return addr to kernel_func_bar  |          30
+ *  return addr to sys_foo          |          20
+ *  return addr to entry            |          10
+ *
+ * The print_max_stack() function above, uses these values to print the size of
+ * each function's portion of the stack.
+ *
+ *  for (i = 0; i < nr_entries; i++) {
+ *     size = i == nr_entries - 1 ? stack_trace_index[i] :
+ *                    stack_trace_index[i] - stack_trace_index[i+1]
+ *     print "%d %d %d %s\n", i, stack_trace_index[i], size, stack_dump_trace[i]);
+ *  }
+ *
+ * The above shows
+ *
+ *     depth size  location
+ *     ----- ----  --------
+ *  0    30   10   kernel_func_bar
+ *  1    20   10   sys_foo
+ *  2    10   10   entry code
+ *
+ * Now for architectures that might save the return address after the functions
+ * local variables (saving the link register before calling nested functions),
+ * this will cause the stack to look a little different:
+ *
+ * [ top of stack ]
+ *  0: sys call entry frame
+ * 10: start of sys_foo_frame
+ * 19: return addr to entry code << lr saved before calling kernel_func_bar
+ * 20: start of kernel_func_bar frame
+ * 29: return addr to sys_foo_frame << lr saved before calling next function
+ * 30: [ do trace stack here ]
+ *
+ * Although the functions returned by save_stack_trace() may be the same, the
+ * placement in the stack will be different. Using the same algorithm as above
+ * would yield:
+ *
+ *        stack_dump_trace[]        |   stack_trace_index[]
+ *        ------------------        +   -------------------
+ *  return addr to kernel_func_bar  |          30
+ *  return addr to sys_foo          |          29
+ *  return addr to entry            |          19
+ *
+ * Where the mapping is off by one:
+ *
+ *   kernel_func_bar stack frame size is 29 - 19 not 30 - 29!
+ *
+ * To fix this, if the architecture sets ARCH_RET_ADDR_AFTER_LOCAL_VARS the
+ * values in stack_trace_index[] are shifted by one to and the number of
+ * stack trace entries is decremented by one.
+ *
+ *        stack_dump_trace[]        |   stack_trace_index[]
+ *        ------------------        +   -------------------
+ *  return addr to kernel_func_bar  |          29
+ *  return addr to sys_foo          |          19
+ *
+ * Although the entry function is not displayed, the first function (sys_foo)
+ * will still include the stack size of it.
+ */
 static void check_stack(unsigned long ip, unsigned long *stack)
 {
 	unsigned long this_size, flags; unsigned long *p, *top, *start;
@@ -158,6 +256,20 @@ static void check_stack(unsigned long ip, unsigned long *stack)
 			i++;
 	}
 
+#ifdef ARCH_FTRACE_SHIFT_STACK_TRACER
+	/*
+	 * Some archs will store the link register before calling
+	 * nested functions. This means the saved return address
+	 * comes after the local storage, and we need to shift
+	 * for that.
+	 */
+	if (x > 1) {
+		memmove(&stack_trace_index[0], &stack_trace_index[1],
+			sizeof(stack_trace_index[0]) * (x - 1));
+		x--;
+	}
+#endif
+
 	stack_trace_nr_entries = x;
 
 	if (task_stack_end_corrupted(current)) {

kernel/trace/trace_uprobe.c

@@ -44,7 +44,7 @@ static int trace_uprobe_show(struct seq_file *m, struct dyn_event *ev);
 static int trace_uprobe_release(struct dyn_event *ev);
 static bool trace_uprobe_is_busy(struct dyn_event *ev);
 static bool trace_uprobe_match(const char *system, const char *event,
-			       struct dyn_event *ev);
+			int argc, const char **argv, struct dyn_event *ev);
 
 static struct dyn_event_operations trace_uprobe_ops = {
 	.create = trace_uprobe_create,
@@ -248,6 +248,9 @@ process_fetch_insn(struct fetch_insn *code, struct pt_regs *regs, void *dest,
 	case FETCH_OP_COMM:
 		val = FETCH_TOKEN_COMM;
 		break;
+	case FETCH_OP_DATA:
+		val = (unsigned long)code->data;
+		break;
 	case FETCH_OP_FOFFS:
 		val = translate_user_vaddr(code->immediate);
 		break;
@@ -284,13 +287,54 @@ static bool trace_uprobe_is_busy(struct dyn_event *ev)
 	return trace_probe_is_enabled(&tu->tp);
 }
 
+static bool trace_uprobe_match_command_head(struct trace_uprobe *tu,
+					    int argc, const char **argv)
+{
+	char buf[MAX_ARGSTR_LEN + 1];
+	int len;
+
+	if (!argc)
+		return true;
+
+	len = strlen(tu->filename);
+	if (strncmp(tu->filename, argv[0], len) || argv[0][len] != ':')
+		return false;
+
+	if (tu->ref_ctr_offset == 0)
+		snprintf(buf, sizeof(buf), "0x%0*lx",
+				(int)(sizeof(void *) * 2), tu->offset);
+	else
+		snprintf(buf, sizeof(buf), "0x%0*lx(0x%lx)",
+				(int)(sizeof(void *) * 2), tu->offset,
+				tu->ref_ctr_offset);
+	if (strcmp(buf, &argv[0][len + 1]))
+		return false;
+
+	argc--; argv++;
+
+	return trace_probe_match_command_args(&tu->tp, argc, argv);
+}
+
 static bool trace_uprobe_match(const char *system, const char *event,
-			       struct dyn_event *ev)
+			int argc, const char **argv, struct dyn_event *ev)
 {
 	struct trace_uprobe *tu = to_trace_uprobe(ev);
 
 	return strcmp(trace_probe_name(&tu->tp), event) == 0 &&
-	    (!system || strcmp(trace_probe_group_name(&tu->tp), system) == 0);
+	   (!system || strcmp(trace_probe_group_name(&tu->tp), system) == 0) &&
+	   trace_uprobe_match_command_head(tu, argc, argv);
+}
+
+static nokprobe_inline struct trace_uprobe *
+trace_uprobe_primary_from_call(struct trace_event_call *call)
+{
+	struct trace_probe *tp;
+
+	tp = trace_probe_primary_from_call(call);
+	if (WARN_ON_ONCE(!tp))
+		return NULL;
+
+	return container_of(tp, struct trace_uprobe, tp);
 }
 
 /*
@@ -352,15 +396,75 @@ static int unregister_trace_uprobe(struct trace_uprobe *tu)
 {
 	int ret;
 
+	if (trace_probe_has_sibling(&tu->tp))
+		goto unreg;
+
 	ret = unregister_uprobe_event(tu);
 	if (ret)
 		return ret;
 
+unreg:
 	dyn_event_remove(&tu->devent);
+	trace_probe_unlink(&tu->tp);
 	free_trace_uprobe(tu);
 	return 0;
 }
 
+static bool trace_uprobe_has_same_uprobe(struct trace_uprobe *orig,
+					 struct trace_uprobe *comp)
+{
+	struct trace_probe_event *tpe = orig->tp.event;
+	struct trace_probe *pos;
+	struct inode *comp_inode = d_real_inode(comp->path.dentry);
+	int i;
+
+	list_for_each_entry(pos, &tpe->probes, list) {
+		orig = container_of(pos, struct trace_uprobe, tp);
+		if (comp_inode != d_real_inode(orig->path.dentry) ||
+		    comp->offset != orig->offset)
+			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))
+				continue;
+		}
+
+		return true;
+	}
+
+	return false;
+}
+
+static int append_trace_uprobe(struct trace_uprobe *tu, struct trace_uprobe *to)
+{
+	int ret;
+
+	ret = trace_probe_compare_arg_type(&tu->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_uprobe_has_same_uprobe(to, tu)) {
+		trace_probe_log_set_index(0);
+		trace_probe_log_err(0, SAME_PROBE);
+		return -EEXIST;
+	}
+
+	/* Append to existing event */
+	ret = trace_probe_append(&tu->tp, &to->tp);
+	if (!ret)
+		dyn_event_add(&tu->devent);
+
+	return ret;
+}
+
 /*
  * Uprobe with multiple reference counter is not allowed. i.e.
  * If inode and offset matches, reference counter offset *must*
@@ -370,25 +474,21 @@ static int unregister_trace_uprobe(struct trace_uprobe *tu)
  * as the new one does not conflict with any other existing
  * ones.
  */
-static struct trace_uprobe *find_old_trace_uprobe(struct trace_uprobe *new)
+static int validate_ref_ctr_offset(struct trace_uprobe *new)
 {
 	struct dyn_event *pos;
-	struct trace_uprobe *tmp, *old = NULL;
+	struct trace_uprobe *tmp;
 	struct inode *new_inode = d_real_inode(new->path.dentry);
 
-	old = find_probe_event(trace_probe_name(&new->tp),
-				trace_probe_group_name(&new->tp));
-
 	for_each_trace_uprobe(tmp, pos) {
-		if ((old ? old != tmp : true) &&
+		if (new_inode == d_real_inode(tmp->path.dentry) &&
-		    new_inode == d_real_inode(tmp->path.dentry) &&
 		    new->offset == tmp->offset &&
 		    new->ref_ctr_offset != tmp->ref_ctr_offset) {
 			pr_warn("Reference counter offset mismatch.");
-			return ERR_PTR(-EINVAL);
+			return -EINVAL;
 		}
 	}
-	return old;
+	return 0;
 }
 
 /* Register a trace_uprobe and probe_event */
@@ -399,18 +499,22 @@ static int register_trace_uprobe(struct trace_uprobe *tu)
 
 	mutex_lock(&event_mutex);
 
-	/* register as an event */
+	ret = validate_ref_ctr_offset(tu);
-	old_tu = find_old_trace_uprobe(tu);
+	if (ret)
-	if (IS_ERR(old_tu)) {
-		ret = PTR_ERR(old_tu);
 		goto end;
-	}
 
+	/* register as an event */
+	old_tu = find_probe_event(trace_probe_name(&tu->tp),
+				  trace_probe_group_name(&tu->tp));
 	if (old_tu) {
-		/* delete old event */
+		if (is_ret_probe(tu) != is_ret_probe(old_tu)) {
-		ret = unregister_trace_uprobe(old_tu);
+			trace_probe_log_set_index(0);
-		if (ret)
+			trace_probe_log_err(0, DIFF_PROBE_TYPE);
-			goto end;
+			ret = -EEXIST;
+		} else {
+			ret = append_trace_uprobe(tu, old_tu);
+		}
+		goto end;
 	}
 
 	ret = register_uprobe_event(tu);
@@ -897,7 +1001,10 @@ print_uprobe_event(struct trace_iterator *iter, int flags, struct trace_event *e
 	u8 *data;
 
 	entry = (struct uprobe_trace_entry_head *)iter->ent;
-	tu = container_of(event, struct trace_uprobe, tp.call.event);
+	tu = trace_uprobe_primary_from_call(
+		container_of(event, struct trace_event_call, event));
+	if (unlikely(!tu))
+		goto out;
 
 	if (is_ret_probe(tu)) {
 		trace_seq_printf(s, "%s: (0x%lx <- 0x%lx)",
@@ -924,27 +1031,71 @@ typedef bool (*filter_func_t)(struct uprobe_consumer *self,
 				enum uprobe_filter_ctx ctx,
 				struct mm_struct *mm);
 
-static int
+static int trace_uprobe_enable(struct trace_uprobe *tu, filter_func_t filter)
-probe_event_enable(struct trace_uprobe *tu, struct trace_event_file *file,
-		   filter_func_t filter)
 {
-	bool enabled = trace_probe_is_enabled(&tu->tp);
 	int ret;
 
+	tu->consumer.filter = filter;
+	tu->inode = d_real_inode(tu->path.dentry);
+
+	if (tu->ref_ctr_offset)
+		ret = uprobe_register_refctr(tu->inode, tu->offset,
+				tu->ref_ctr_offset, &tu->consumer);
+	else
+		ret = uprobe_register(tu->inode, tu->offset, &tu->consumer);
+
+	if (ret)
+		tu->inode = NULL;
+
+	return ret;
+}
+
+static void __probe_event_disable(struct trace_probe *tp)
+{
+	struct trace_probe *pos;
+	struct trace_uprobe *tu;
+
+	list_for_each_entry(pos, trace_probe_probe_list(tp), list) {
+		tu = container_of(pos, struct trace_uprobe, tp);
+		if (!tu->inode)
+			continue;
+
+		WARN_ON(!uprobe_filter_is_empty(&tu->filter));
+
+		uprobe_unregister(tu->inode, tu->offset, &tu->consumer);
+		tu->inode = NULL;
+	}
+}
+
+static int probe_event_enable(struct trace_event_call *call,
+			struct trace_event_file *file, filter_func_t filter)
+{
+	struct trace_probe *pos, *tp;
+	struct trace_uprobe *tu;
+	bool enabled;
+	int ret;
+
+	tp = trace_probe_primary_from_call(call);
+	if (WARN_ON_ONCE(!tp))
+		return -ENODEV;
+	enabled = trace_probe_is_enabled(tp);
+
+	/* This may also change "enabled" state */
 	if (file) {
-		if (trace_probe_test_flag(&tu->tp, TP_FLAG_PROFILE))
+		if (trace_probe_test_flag(tp, TP_FLAG_PROFILE))
 			return -EINTR;
 
-		ret = trace_probe_add_file(&tu->tp, file);
+		ret = trace_probe_add_file(tp, file);
 		if (ret < 0)
 			return ret;
 	} else {
-		if (trace_probe_test_flag(&tu->tp, TP_FLAG_TRACE))
+		if (trace_probe_test_flag(tp, TP_FLAG_TRACE))
 			return -EINTR;
 
-		trace_probe_set_flag(&tu->tp, TP_FLAG_PROFILE);
+		trace_probe_set_flag(tp, TP_FLAG_PROFILE);
 	}
 
+	tu = container_of(tp, struct trace_uprobe, tp);
 	WARN_ON(!uprobe_filter_is_empty(&tu->filter));
 
 	if (enabled)
@@ -954,18 +1105,15 @@ probe_event_enable(struct trace_uprobe *tu, struct trace_event_file *file,
 	if (ret)
 		goto err_flags;
 
-	tu->consumer.filter = filter;
+	list_for_each_entry(pos, trace_probe_probe_list(tp), list) {
-	tu->inode = d_real_inode(tu->path.dentry);
+		tu = container_of(pos, struct trace_uprobe, tp);
-	if (tu->ref_ctr_offset) {
+		ret = trace_uprobe_enable(tu, filter);
-		ret = uprobe_register_refctr(tu->inode, tu->offset,
+		if (ret) {
-				tu->ref_ctr_offset, &tu->consumer);
+			__probe_event_disable(tp);
-	} else {
+			goto err_buffer;
-		ret = uprobe_register(tu->inode, tu->offset, &tu->consumer);
+		}
 	}
 
-	if (ret)
-		goto err_buffer;
-
 	return 0;
 
  err_buffer:
@@ -973,33 +1121,35 @@ probe_event_enable(struct trace_uprobe *tu, struct trace_event_file *file,
 
  err_flags:
 	if (file)
-		trace_probe_remove_file(&tu->tp, file);
+		trace_probe_remove_file(tp, file);
 	else
-		trace_probe_clear_flag(&tu->tp, TP_FLAG_PROFILE);
+		trace_probe_clear_flag(tp, TP_FLAG_PROFILE);
 
 	return ret;
 }
 
-static void
+static void probe_event_disable(struct trace_event_call *call,
-probe_event_disable(struct trace_uprobe *tu, struct trace_event_file *file)
+				struct trace_event_file *file)
 {
-	if (!trace_probe_is_enabled(&tu->tp))
+	struct trace_probe *tp;
+
+	tp = trace_probe_primary_from_call(call);
+	if (WARN_ON_ONCE(!tp))
+		return;
+
+	if (!trace_probe_is_enabled(tp))
 		return;
 
 	if (file) {
-		if (trace_probe_remove_file(&tu->tp, file) < 0)
+		if (trace_probe_remove_file(tp, file) < 0)
 			return;
 
-		if (trace_probe_is_enabled(&tu->tp))
+		if (trace_probe_is_enabled(tp))
 			return;
 	} else
-		trace_probe_clear_flag(&tu->tp, TP_FLAG_PROFILE);
+		trace_probe_clear_flag(tp, TP_FLAG_PROFILE);
-
-	WARN_ON(!uprobe_filter_is_empty(&tu->filter));
-
-	uprobe_unregister(tu->inode, tu->offset, &tu->consumer);
-	tu->inode = NULL;
 
+	__probe_event_disable(tp);
 	uprobe_buffer_disable();
 }
 
@@ -1007,7 +1157,11 @@ static int uprobe_event_define_fields(struct trace_event_call *event_call)
 {
 	int ret, size;
 	struct uprobe_trace_entry_head field;
-	struct trace_uprobe *tu = event_call->data;
+	struct trace_uprobe *tu;
+
+	tu = trace_uprobe_primary_from_call(event_call);
+	if (unlikely(!tu))
+		return -ENODEV;
 
 	if (is_ret_probe(tu)) {
 		DEFINE_FIELD(unsigned long, vaddr[0], FIELD_STRING_FUNC, 0);
@@ -1100,6 +1254,27 @@ static int uprobe_perf_open(struct trace_uprobe *tu, struct perf_event *event)
 	return err;
 }
 
+static int uprobe_perf_multi_call(struct trace_event_call *call,
+				  struct perf_event *event,
+		int (*op)(struct trace_uprobe *tu, struct perf_event *event))
+{
+	struct trace_probe *pos, *tp;
+	struct trace_uprobe *tu;
+	int ret = 0;
+
+	tp = trace_probe_primary_from_call(call);
+	if (WARN_ON_ONCE(!tp))
+		return -ENODEV;
+
+	list_for_each_entry(pos, trace_probe_probe_list(tp), list) {
+		tu = container_of(pos, struct trace_uprobe, tp);
+		ret = op(tu, event);
+		if (ret)
+			break;
+	}
+
+	return ret;
+}
 static bool uprobe_perf_filter(struct uprobe_consumer *uc,
 				enum uprobe_filter_ctx ctx, struct mm_struct *mm)
 {
@@ -1213,30 +1388,29 @@ static int
 trace_uprobe_register(struct trace_event_call *event, enum trace_reg type,
 		      void *data)
 {
-	struct trace_uprobe *tu = event->data;
 	struct trace_event_file *file = data;
 
 	switch (type) {
 	case TRACE_REG_REGISTER:
-		return probe_event_enable(tu, file, NULL);
+		return probe_event_enable(event, file, NULL);
 
 	case TRACE_REG_UNREGISTER:
-		probe_event_disable(tu, file);
+		probe_event_disable(event, file);
 		return 0;
 
 #ifdef CONFIG_PERF_EVENTS
 	case TRACE_REG_PERF_REGISTER:
-		return probe_event_enable(tu, NULL, uprobe_perf_filter);
+		return probe_event_enable(event, NULL, uprobe_perf_filter);
 
 	case TRACE_REG_PERF_UNREGISTER:
-		probe_event_disable(tu, NULL);
+		probe_event_disable(event, NULL);
 		return 0;
 
 	case TRACE_REG_PERF_OPEN:
-		return uprobe_perf_open(tu, data);
+		return uprobe_perf_multi_call(event, data, uprobe_perf_open);
 
 	case TRACE_REG_PERF_CLOSE:
-		return uprobe_perf_close(tu, data);
+		return uprobe_perf_multi_call(event, data, uprobe_perf_close);
 
 #endif
 	default:
@@ -1330,7 +1504,6 @@ static inline void init_trace_event_call(struct trace_uprobe *tu)
 
 	call->flags = TRACE_EVENT_FL_UPROBE | TRACE_EVENT_FL_CAP_ANY;
 	call->class->reg = trace_uprobe_register;
-	call->data = tu;
 }
 
 static int register_uprobe_event(struct trace_uprobe *tu)
@@ -1399,7 +1572,7 @@ void destroy_local_trace_uprobe(struct trace_event_call *event_call)
 {
 	struct trace_uprobe *tu;
 
-	tu = container_of(event_call, struct trace_uprobe, tp.call);
+	tu = trace_uprobe_primary_from_call(event_call);
 
 	free_trace_uprobe(tu);
 }

scripts/recordmcount.c

@@ -27,7 +27,6 @@
 #include <getopt.h>
 #include <elf.h>
 #include <fcntl.h>
-#include <setjmp.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -43,56 +42,37 @@ static int fd_map;	/* File descriptor for file being modified. */
 static int mmap_failed; /* Boolean flag. */
 static char gpfx;	/* prefix for global symbol name (sometimes '_') */
 static struct stat sb;	/* Remember .st_size, etc. */
-static jmp_buf jmpenv;	/* setjmp/longjmp per-file error escape */
 static const char *altmcount;	/* alternate mcount symbol name */
 static int warn_on_notrace_sect; /* warn when section has mcount not being recorded */
 static void *file_map;	/* pointer of the mapped file */
 static void *file_end;	/* pointer to the end of the mapped file */
 static int file_updated; /* flag to state file was changed */
 static void *file_ptr;	/* current file pointer location */
+
 static void *file_append; /* added to the end of the file */
 static size_t file_append_size; /* how much is added to end of file */
 
-/* setjmp() return values */
-enum {
-	SJ_SETJMP = 0,  /* hardwired first return */
-	SJ_FAIL,
-	SJ_SUCCEED
-};
-
 /* Per-file resource cleanup when multiple files. */
-static void
+static void file_append_cleanup(void)
-cleanup(void)
 {
-	if (!mmap_failed)
-		munmap(file_map, sb.st_size);
-	else
-		free(file_map);
-	file_map = NULL;
 	free(file_append);
 	file_append = NULL;
 	file_append_size = 0;
 	file_updated = 0;
 }
 
-static void __attribute__((noreturn))
+static void mmap_cleanup(void)
-fail_file(void)
 {
-	cleanup();
+	if (!mmap_failed)
-	longjmp(jmpenv, SJ_FAIL);
+		munmap(file_map, sb.st_size);
+	else
+		free(file_map);
+	file_map = NULL;
 }
 
-static void __attribute__((noreturn))
+/* ulseek, uwrite, ...:  Check return value for errors. */
-succeed_file(void)
-{
-	cleanup();
-	longjmp(jmpenv, SJ_SUCCEED);
-}
 
-/* ulseek, uread, ...:  Check return value for errors. */
+static off_t ulseek(off_t const offset, int const whence)
-
-static off_t
-ulseek(int const fd, off_t const offset, int const whence)
 {
 	switch (whence) {
 	case SEEK_SET:
@@ -107,24 +87,12 @@ ulseek(int const fd, off_t const offset, int const whence)
 	}
 	if (file_ptr < file_map) {
 		fprintf(stderr, "lseek: seek before file\n");
-		fail_file();
+		return -1;
 	}
 	return file_ptr - file_map;
 }
 
-static size_t
+static ssize_t uwrite(void const *const buf, size_t const count)
-uread(int const fd, void *const buf, size_t const count)
-{
-	size_t const n = read(fd, buf, count);
-	if (n != count) {
-		perror("read");
-		fail_file();
-	}
-	return n;
-}
-
-static size_t
-uwrite(int const fd, void const *const buf, size_t const count)
 {
 	size_t cnt = count;
 	off_t idx = 0;
@@ -140,7 +108,9 @@ uwrite(int const fd, void const *const buf, size_t const count)
 		}
 		if (!file_append) {
 			perror("write");
-			fail_file();
+			file_append_cleanup();
+			mmap_cleanup();
+			return -1;
 		}
 		if (file_ptr < file_end) {
 			cnt = file_end - file_ptr;
@@ -160,17 +130,81 @@ uwrite(int const fd, void const *const buf, size_t const count)
 	return count;
 }
 
-static void *
+static void * umalloc(size_t size)
-umalloc(size_t size)
 {
 	void *const addr = malloc(size);
 	if (addr == 0) {
 		fprintf(stderr, "malloc failed: %zu bytes\n", size);
-		fail_file();
+		file_append_cleanup();
+		mmap_cleanup();
+		return NULL;
 	}
 	return addr;
 }
 
+/*
+ * Get the whole file as a programming convenience in order to avoid
+ * malloc+lseek+read+free of many pieces.  If successful, then mmap
+ * avoids copying unused pieces; else just read the whole file.
+ * Open for both read and write; new info will be appended to the file.
+ * Use MAP_PRIVATE so that a few changes to the in-memory ElfXX_Ehdr
+ * do not propagate to the file until an explicit overwrite at the last.
+ * This preserves most aspects of consistency (all except .st_size)
+ * for simultaneous readers of the file while we are appending to it.
+ * However, multiple writers still are bad.  We choose not to use
+ * locking because it is expensive and the use case of kernel build
+ * makes multiple writers unlikely.
+ */
+static void *mmap_file(char const *fname)
+{
+	/* Avoid problems if early cleanup() */
+	fd_map = -1;
+	mmap_failed = 1;
+	file_map = NULL;
+	file_ptr = NULL;
+	file_updated = 0;
+	sb.st_size = 0;
+
+	fd_map = open(fname, O_RDONLY);
+	if (fd_map < 0) {
+		perror(fname);
+		return NULL;
+	}
+	if (fstat(fd_map, &sb) < 0) {
+		perror(fname);
+		goto out;
+	}
+	if (!S_ISREG(sb.st_mode)) {
+		fprintf(stderr, "not a regular file: %s\n", fname);
+		goto out;
+	}
+	file_map = mmap(0, sb.st_size, PROT_READ|PROT_WRITE, MAP_PRIVATE,
+			fd_map, 0);
+	if (file_map == MAP_FAILED) {
+		mmap_failed = 1;
+		file_map = umalloc(sb.st_size);
+		if (!file_map) {
+			perror(fname);
+			goto out;
+		}
+		if (read(fd_map, file_map, sb.st_size) != sb.st_size) {
+			perror(fname);
+			free(file_map);
+			file_map = NULL;
+			goto out;
+		}
+	} else
+		mmap_failed = 0;
+out:
+	close(fd_map);
+	fd_map = -1;
+
+	file_end = file_map + sb.st_size;
+
+	return file_map;
+}
+
+
 static unsigned char ideal_nop5_x86_64[5] = { 0x0f, 0x1f, 0x44, 0x00, 0x00 };
 static unsigned char ideal_nop5_x86_32[5] = { 0x3e, 0x8d, 0x74, 0x26, 0x00 };
 static unsigned char *ideal_nop;
@@ -194,8 +228,10 @@ static int make_nop_x86(void *map, size_t const offset)
 		return -1;
 
 	/* convert to nop */
-	ulseek(fd_map, offset - 1, SEEK_SET);
+	if (ulseek(offset - 1, SEEK_SET) < 0)
-	uwrite(fd_map, ideal_nop, 5);
+		return -1;
+	if (uwrite(ideal_nop, 5) < 0)
+		return -1;
 	return 0;
 }
 
@@ -243,10 +279,12 @@ static int make_nop_arm(void *map, size_t const offset)
 		return -1;
 
 	/* Convert to nop */
-	ulseek(fd_map, off, SEEK_SET);
+	if (ulseek(off, SEEK_SET) < 0)
+		return -1;
 
 	do {
-		uwrite(fd_map, ideal_nop, nop_size);
+		if (uwrite(ideal_nop, nop_size) < 0)
+			return -1;
 	} while (--cnt > 0);
 
 	return 0;
@@ -263,57 +301,20 @@ static int make_nop_arm64(void *map, size_t const offset)
 		return -1;
 
 	/* Convert to nop */
-	ulseek(fd_map, offset, SEEK_SET);
+	if (ulseek(offset, SEEK_SET) < 0)
-	uwrite(fd_map, ideal_nop, 4);
+		return -1;
+	if (uwrite(ideal_nop, 4) < 0)
+		return -1;
 	return 0;
 }
 
-/*
+static int write_file(const char *fname)
- * Get the whole file as a programming convenience in order to avoid
- * malloc+lseek+read+free of many pieces.  If successful, then mmap
- * avoids copying unused pieces; else just read the whole file.
- * Open for both read and write; new info will be appended to the file.
- * Use MAP_PRIVATE so that a few changes to the in-memory ElfXX_Ehdr
- * do not propagate to the file until an explicit overwrite at the last.
- * This preserves most aspects of consistency (all except .st_size)
- * for simultaneous readers of the file while we are appending to it.
- * However, multiple writers still are bad.  We choose not to use
- * locking because it is expensive and the use case of kernel build
- * makes multiple writers unlikely.
- */
-static void *mmap_file(char const *fname)
-{
-	fd_map = open(fname, O_RDONLY);
-	if (fd_map < 0 || fstat(fd_map, &sb) < 0) {
-		perror(fname);
-		fail_file();
-	}
-	if (!S_ISREG(sb.st_mode)) {
-		fprintf(stderr, "not a regular file: %s\n", fname);
-		fail_file();
-	}
-	file_map = mmap(0, sb.st_size, PROT_READ|PROT_WRITE, MAP_PRIVATE,
-			fd_map, 0);
-	mmap_failed = 0;
-	if (file_map == MAP_FAILED) {
-		mmap_failed = 1;
-		file_map = umalloc(sb.st_size);
-		uread(fd_map, file_map, sb.st_size);
-	}
-	close(fd_map);
-
-	file_end = file_map + sb.st_size;
-
-	return file_map;
-}
-
-static void write_file(const char *fname)
 {
 	char tmp_file[strlen(fname) + 4];
 	size_t n;
 
 	if (!file_updated)
-		return;
+		return 0;
 
 	sprintf(tmp_file, "%s.rc", fname);
 
@@ -325,25 +326,28 @@ static void write_file(const char *fname)
 	fd_map = open(tmp_file, O_WRONLY | O_TRUNC | O_CREAT, sb.st_mode);
 	if (fd_map < 0) {
 		perror(fname);
-		fail_file();
+		return -1;
 	}
 	n = write(fd_map, file_map, sb.st_size);
 	if (n != sb.st_size) {
 		perror("write");
-		fail_file();
+		close(fd_map);
+		return -1;
 	}
 	if (file_append_size) {
 		n = write(fd_map, file_append, file_append_size);
 		if (n != file_append_size) {
 			perror("write");
-			fail_file();
+			close(fd_map);
+			return -1;
 		}
 	}
 	close(fd_map);
 	if (rename(tmp_file, fname) < 0) {
 		perror(fname);
-		fail_file();
+		return -1;
 	}
+	return 0;
 }
 
 /* w8rev, w8nat, ...: Handle endianness. */
@@ -394,8 +398,7 @@ static uint32_t (*w)(uint32_t);
 static uint32_t (*w2)(uint16_t);
 
 /* Names of the sections that could contain calls to mcount. */
-static int
+static int is_mcounted_section_name(char const *const txtname)
-is_mcounted_section_name(char const *const txtname)
 {
 	return strncmp(".text",          txtname, 5) == 0 ||
 		strcmp(".init.text",     txtname) == 0 ||
@@ -405,10 +408,11 @@ is_mcounted_section_name(char const *const txtname)
 		strcmp(".irqentry.text", txtname) == 0 ||
 		strcmp(".softirqentry.text", txtname) == 0 ||
 		strcmp(".kprobes.text", txtname) == 0 ||
-		strcmp(".cpuidle.text", txtname) == 0 ||
+		strcmp(".cpuidle.text", txtname) == 0;
-		strcmp(".text.unlikely", txtname) == 0;
 }
 
+static char const *already_has_rel_mcount = "success"; /* our work here is done! */
+
 /* 32 bit and 64 bit are very similar */
 #include "recordmcount.h"
 #define RECORD_MCOUNT_64
@@ -447,11 +451,15 @@ static void MIPS64_r_info(Elf64_Rel *const rp, unsigned sym, unsigned type)
 	}).r_info;
 }
 
-static void
+static int do_file(char const *const fname)
-do_file(char const *const fname)
 {
-	Elf32_Ehdr *const ehdr = mmap_file(fname);
 	unsigned int reltype = 0;
+	Elf32_Ehdr *ehdr;
+	int rc = -1;
+
+	ehdr = mmap_file(fname);
+	if (!ehdr)
+		goto out;
 
 	w = w4nat;
 	w2 = w2nat;
@@ -461,8 +469,7 @@ do_file(char const *const fname)
 	default:
 		fprintf(stderr, "unrecognized ELF data encoding %d: %s\n",
 			ehdr->e_ident[EI_DATA], fname);
-		fail_file();
+		goto out;
-		break;
 	case ELFDATA2LSB:
 		if (*(unsigned char const *)&endian != 1) {
 			/* main() is big endian, file.o is little endian. */
@@ -490,52 +497,54 @@ do_file(char const *const fname)
 		push_bl_mcount_thumb = push_bl_mcount_thumb_be;
 		break;
 	}  /* end switch */
-	if (memcmp(ELFMAG, ehdr->e_ident, SELFMAG) != 0
+	if (memcmp(ELFMAG, ehdr->e_ident, SELFMAG) != 0 ||
-	||  w2(ehdr->e_type) != ET_REL
+	    w2(ehdr->e_type) != ET_REL ||
-	||  ehdr->e_ident[EI_VERSION] != EV_CURRENT) {
+	    ehdr->e_ident[EI_VERSION] != EV_CURRENT) {
 		fprintf(stderr, "unrecognized ET_REL file %s\n", fname);
-		fail_file();
+		goto out;
 	}
 
-	gpfx = 0;
+	gpfx = '_';
 	switch (w2(ehdr->e_machine)) {
 	default:
 		fprintf(stderr, "unrecognized e_machine %u %s\n",
 			w2(ehdr->e_machine), fname);
-		fail_file();
+		goto out;
-		break;
 	case EM_386:
 		reltype = R_386_32;
 		rel_type_nop = R_386_NONE;
 		make_nop = make_nop_x86;
 		ideal_nop = ideal_nop5_x86_32;
 		mcount_adjust_32 = -1;
+		gpfx = 0;
+		break;
+	case EM_ARM:
+		reltype = R_ARM_ABS32;
+		altmcount = "__gnu_mcount_nc";
+		make_nop = make_nop_arm;
+		rel_type_nop = R_ARM_NONE;
+		gpfx = 0;
 		break;
-	case EM_ARM:	 reltype = R_ARM_ABS32;
-			 altmcount = "__gnu_mcount_nc";
-			 make_nop = make_nop_arm;
-			 rel_type_nop = R_ARM_NONE;
-			 break;
 	case EM_AARCH64:
-			reltype = R_AARCH64_ABS64;
+		reltype = R_AARCH64_ABS64;
-			make_nop = make_nop_arm64;
+		make_nop = make_nop_arm64;
-			rel_type_nop = R_AARCH64_NONE;
+		rel_type_nop = R_AARCH64_NONE;
-			ideal_nop = ideal_nop4_arm64;
+		ideal_nop = ideal_nop4_arm64;
-			gpfx = '_';
+		break;
-			break;
+	case EM_IA_64:	reltype = R_IA64_IMM64; break;
-	case EM_IA_64:	 reltype = R_IA64_IMM64;   gpfx = '_'; break;
+	case EM_MIPS:	/* reltype: e_class    */ break;
-	case EM_MIPS:	 /* reltype: e_class    */ gpfx = '_'; break;
+	case EM_PPC:	reltype = R_PPC_ADDR32; break;
-	case EM_PPC:	 reltype = R_PPC_ADDR32;   gpfx = '_'; break;
+	case EM_PPC64:	reltype = R_PPC64_ADDR64; break;
-	case EM_PPC64:	 reltype = R_PPC64_ADDR64; gpfx = '_'; break;
+	case EM_S390:	/* reltype: e_class    */ break;
-	case EM_S390:    /* reltype: e_class    */ gpfx = '_'; break;
+	case EM_SH:	reltype = R_SH_DIR32; gpfx = 0; break;
-	case EM_SH:	 reltype = R_SH_DIR32;                 break;
+	case EM_SPARCV9: reltype = R_SPARC_64; break;
-	case EM_SPARCV9: reltype = R_SPARC_64;     gpfx = '_'; break;
 	case EM_X86_64:
 		make_nop = make_nop_x86;
 		ideal_nop = ideal_nop5_x86_64;
 		reltype = R_X86_64_64;
 		rel_type_nop = R_X86_64_NONE;
 		mcount_adjust_64 = -1;
+		gpfx = 0;
 		break;
 	}  /* end switch */
 
@@ -543,20 +552,20 @@ do_file(char const *const fname)
 	default:
 		fprintf(stderr, "unrecognized ELF class %d %s\n",
 			ehdr->e_ident[EI_CLASS], fname);
-		fail_file();
+		goto out;
-		break;
 	case ELFCLASS32:
 		if (w2(ehdr->e_ehsize) != sizeof(Elf32_Ehdr)
 		||  w2(ehdr->e_shentsize) != sizeof(Elf32_Shdr)) {
 			fprintf(stderr,
 				"unrecognized ET_REL file: %s\n", fname);
-			fail_file();
+			goto out;
 		}
 		if (w2(ehdr->e_machine) == EM_MIPS) {
 			reltype = R_MIPS_32;
 			is_fake_mcount32 = MIPS32_is_fake_mcount;
 		}
-		do32(ehdr, fname, reltype);
+		if (do32(ehdr, fname, reltype) < 0)
+			goto out;
 		break;
 	case ELFCLASS64: {
 		Elf64_Ehdr *const ghdr = (Elf64_Ehdr *)ehdr;
@@ -564,7 +573,7 @@ do_file(char const *const fname)
 		||  w2(ghdr->e_shentsize) != sizeof(Elf64_Shdr)) {
 			fprintf(stderr,
 				"unrecognized ET_REL file: %s\n", fname);
-			fail_file();
+			goto out;
 		}
 		if (w2(ghdr->e_machine) == EM_S390) {
 			reltype = R_390_64;
@@ -576,17 +585,20 @@ do_file(char const *const fname)
 			Elf64_r_info = MIPS64_r_info;
 			is_fake_mcount64 = MIPS64_is_fake_mcount;
 		}
-		do64(ghdr, fname, reltype);
+		if (do64(ghdr, fname, reltype) < 0)
+			goto out;
 		break;
 	}
 	}  /* end switch */
 
-	write_file(fname);
+	rc = write_file(fname);
-	cleanup();
+out:
+	file_append_cleanup();
+	mmap_cleanup();
+	return rc;
 }
 
-int
+int main(int argc, char *argv[])
-main(int argc, char *argv[])
 {
 	const char ftrace[] = "/ftrace.o";
 	int ftrace_size = sizeof(ftrace) - 1;
@@ -613,7 +625,6 @@ main(int argc, char *argv[])
 	/* Process each file in turn, allowing deep failure. */
 	for (i = optind; i < argc; i++) {
 		char *file = argv[i];
-		int const sjval = setjmp(jmpenv);
 		int len;
 
 		/*
@@ -626,28 +637,10 @@ main(int argc, char *argv[])
 		    strcmp(file + (len - ftrace_size), ftrace) == 0)
 			continue;
 
-		switch (sjval) {
+		if (do_file(file)) {
-		default:
-			fprintf(stderr, "internal error: %s\n", file);
-			exit(1);
-			break;
-		case SJ_SETJMP:    /* normal sequence */
-			/* Avoid problems if early cleanup() */
-			fd_map = -1;
-			mmap_failed = 1;
-			file_map = NULL;
-			file_ptr = NULL;
-			file_updated = 0;
-			do_file(file);
-			break;
-		case SJ_FAIL:    /* error in do_file or below */
 			fprintf(stderr, "%s: failed\n", file);
 			++n_error;
-			break;
+		}
-		case SJ_SUCCEED:    /* premature success */
-			/* do nothing */
-			break;
-		}  /* end switch */
 	}
 	return !!n_error;
 }

scripts/recordmcount.h

@@ -174,7 +174,7 @@ static int MIPS_is_fake_mcount(Elf_Rel const *rp)
 }
 
 /* Append the new shstrtab, Elf_Shdr[], __mcount_loc and its relocations. */
-static void append_func(Elf_Ehdr *const ehdr,
+static int append_func(Elf_Ehdr *const ehdr,
 			Elf_Shdr *const shstr,
 			uint_t const *const mloc0,
 			uint_t const *const mlocp,
@@ -202,15 +202,20 @@ static void append_func(Elf_Ehdr *const ehdr,
 	new_e_shoff = t;
 
 	/* body for new shstrtab */
-	ulseek(fd_map, sb.st_size, SEEK_SET);
+	if (ulseek(sb.st_size, SEEK_SET) < 0)
-	uwrite(fd_map, old_shstr_sh_offset + (void *)ehdr, old_shstr_sh_size);
+		return -1;
-	uwrite(fd_map, mc_name, 1 + strlen(mc_name));
+	if (uwrite(old_shstr_sh_offset + (void *)ehdr, old_shstr_sh_size) < 0)
+		return -1;
+	if (uwrite(mc_name, 1 + strlen(mc_name)) < 0)
+		return -1;
 
 	/* old(modified) Elf_Shdr table, word-byte aligned */
-	ulseek(fd_map, t, SEEK_SET);
+	if (ulseek(t, SEEK_SET) < 0)
+		return -1;
 	t += sizeof(Elf_Shdr) * old_shnum;
-	uwrite(fd_map, old_shoff + (void *)ehdr,
+	if (uwrite(old_shoff + (void *)ehdr,
-	       sizeof(Elf_Shdr) * old_shnum);
+	       sizeof(Elf_Shdr) * old_shnum) < 0)
+		return -1;
 
 	/* new sections __mcount_loc and .rel__mcount_loc */
 	t += 2*sizeof(mcsec);
@@ -225,7 +230,8 @@ static void append_func(Elf_Ehdr *const ehdr,
 	mcsec.sh_info = 0;
 	mcsec.sh_addralign = _w(_size);
 	mcsec.sh_entsize = _w(_size);
-	uwrite(fd_map, &mcsec, sizeof(mcsec));
+	if (uwrite(&mcsec, sizeof(mcsec)) < 0)
+		return -1;
 
 	mcsec.sh_name = w(old_shstr_sh_size);
 	mcsec.sh_type = (sizeof(Elf_Rela) == rel_entsize)
@@ -239,15 +245,22 @@ static void append_func(Elf_Ehdr *const ehdr,
 	mcsec.sh_info = w(old_shnum);
 	mcsec.sh_addralign = _w(_size);
 	mcsec.sh_entsize = _w(rel_entsize);
-	uwrite(fd_map, &mcsec, sizeof(mcsec));
 
-	uwrite(fd_map, mloc0, (void *)mlocp - (void *)mloc0);
+	if (uwrite(&mcsec, sizeof(mcsec)) < 0)
-	uwrite(fd_map, mrel0, (void *)mrelp - (void *)mrel0);
+		return -1;
+
+	if (uwrite(mloc0, (void *)mlocp - (void *)mloc0) < 0)
+		return -1;
+	if (uwrite(mrel0, (void *)mrelp - (void *)mrel0) < 0)
+		return -1;
 
 	ehdr->e_shoff = _w(new_e_shoff);
 	ehdr->e_shnum = w2(2 + w2(ehdr->e_shnum));  /* {.rel,}__mcount_loc */
-	ulseek(fd_map, 0, SEEK_SET);
+	if (ulseek(0, SEEK_SET) < 0)
-	uwrite(fd_map, ehdr, sizeof(*ehdr));
+		return -1;
+	if (uwrite(ehdr, sizeof(*ehdr)) < 0)
+		return -1;
+	return 0;
 }
 
 static unsigned get_mcountsym(Elf_Sym const *const sym0,
@@ -351,9 +364,9 @@ static uint_t *sift_rel_mcount(uint_t *mlocp,
  * that are not going to be traced. The mcount calls here will be converted
  * into nops.
  */
-static void nop_mcount(Elf_Shdr const *const relhdr,
+static int nop_mcount(Elf_Shdr const *const relhdr,
-		       Elf_Ehdr const *const ehdr,
+		      Elf_Ehdr const *const ehdr,
-		       const char *const txtname)
+		      const char *const txtname)
 {
 	Elf_Shdr *const shdr0 = (Elf_Shdr *)(_w(ehdr->e_shoff)
 		+ (void *)ehdr);
@@ -376,15 +389,18 @@ static void nop_mcount(Elf_Shdr const *const relhdr,
 			mcountsym = get_mcountsym(sym0, relp, str0);
 
 		if (mcountsym == Elf_r_sym(relp) && !is_fake_mcount(relp)) {
-			if (make_nop)
+			if (make_nop) {
 				ret = make_nop((void *)ehdr, _w(shdr->sh_offset) + _w(relp->r_offset));
+				if (ret < 0)
+					return -1;
+			}
 			if (warn_on_notrace_sect && !once) {
 				printf("Section %s has mcount callers being ignored\n",
 				       txtname);
 				once = 1;
 				/* just warn? */
 				if (!make_nop)
-					return;
+					return 0;
 			}
 		}
 
@@ -396,14 +412,16 @@ static void nop_mcount(Elf_Shdr const *const relhdr,
 			Elf_Rel rel;
 			rel = *(Elf_Rel *)relp;
 			Elf_r_info(&rel, Elf_r_sym(relp), rel_type_nop);
-			ulseek(fd_map, (void *)relp - (void *)ehdr, SEEK_SET);
+			if (ulseek((void *)relp - (void *)ehdr, SEEK_SET) < 0)
-			uwrite(fd_map, &rel, sizeof(rel));
+				return -1;
+			if (uwrite(&rel, sizeof(rel)) < 0)
+				return -1;
 		}
 		relp = (Elf_Rel const *)(rel_entsize + (void *)relp);
 	}
+	return 0;
 }
 
-
 /*
  * Find a symbol in the given section, to be used as the base for relocating
  * the table of offsets of calls to mcount.  A local or global symbol suffices,
@@ -414,9 +432,10 @@ static void nop_mcount(Elf_Shdr const *const relhdr,
  *    Num:    Value  Size Type    Bind   Vis      Ndx Name
  *      2: 00000000     0 SECTION LOCAL  DEFAULT    1
  */
-static unsigned find_secsym_ndx(unsigned const txtndx,
+static int find_secsym_ndx(unsigned const txtndx,
 				char const *const txtname,
 				uint_t *const recvalp,
+				unsigned int *sym_index,
 				Elf_Shdr const *const symhdr,
 				Elf_Ehdr const *const ehdr)
 {
@@ -438,21 +457,20 @@ static unsigned find_secsym_ndx(unsigned const txtndx,
 				continue;
 
 			*recvalp = _w(symp->st_value);
-			return symp - sym0;
+			*sym_index = symp - sym0;
+			return 0;
 		}
 	}
 	fprintf(stderr, "Cannot find symbol for section %u: %s.\n",
 		txtndx, txtname);
-	fail_file();
+	return -1;
 }
 
-
 /* Evade ISO C restriction: no declaration after statement in has_rel_mcount. */
-static char const *
+static char const * __has_rel_mcount(Elf_Shdr const *const relhdr, /* reltype */
-__has_rel_mcount(Elf_Shdr const *const relhdr,  /* is SHT_REL or SHT_RELA */
+				     Elf_Shdr const *const shdr0,
-		 Elf_Shdr const *const shdr0,
+				     char const *const shstrtab,
-		 char const *const shstrtab,
+				     char const *const fname)
-		 char const *const fname)
 {
 	/* .sh_info depends on .sh_type == SHT_REL[,A] */
 	Elf_Shdr const *const txthdr = &shdr0[w(relhdr->sh_info)];
@@ -461,7 +479,7 @@ __has_rel_mcount(Elf_Shdr const *const relhdr,  /* is SHT_REL or SHT_RELA */
 	if (strcmp("__mcount_loc", txtname) == 0) {
 		fprintf(stderr, "warning: __mcount_loc already exists: %s\n",
 			fname);
-		succeed_file();
+		return already_has_rel_mcount;
 	}
 	if (w(txthdr->sh_type) != SHT_PROGBITS ||
 	    !(_w(txthdr->sh_flags) & SHF_EXECINSTR))
@@ -491,6 +509,10 @@ static unsigned tot_relsize(Elf_Shdr const *const shdr0,
 
 	for (; nhdr; --nhdr, ++shdrp) {
 		txtname = has_rel_mcount(shdrp, shdr0, shstrtab, fname);
+		if (txtname == already_has_rel_mcount) {
+			totrelsz = 0;
+			break;
+		}
 		if (txtname && is_mcounted_section_name(txtname))
 			totrelsz += _w(shdrp->sh_size);
 	}
@@ -499,8 +521,8 @@ static unsigned tot_relsize(Elf_Shdr const *const shdr0,
 
 
 /* Overall supervision for Elf32 ET_REL file. */
-static void
+static int do_func(Elf_Ehdr *const ehdr, char const *const fname,
-do_func(Elf_Ehdr *const ehdr, char const *const fname, unsigned const reltype)
+		   unsigned const reltype)
 {
 	Elf_Shdr *const shdr0 = (Elf_Shdr *)(_w(ehdr->e_shoff)
 		+ (void *)ehdr);
@@ -513,26 +535,54 @@ do_func(Elf_Ehdr *const ehdr, char const *const fname, unsigned const reltype)
 	unsigned k;
 
 	/* Upper bound on space: assume all relevant relocs are for mcount. */
-	unsigned const totrelsz = tot_relsize(shdr0, nhdr, shstrtab, fname);
+	unsigned       totrelsz;
-	Elf_Rel *const mrel0 = umalloc(totrelsz);
-	Elf_Rel *      mrelp = mrel0;
 
-	/* 2*sizeof(address) <= sizeof(Elf_Rel) */
+	Elf_Rel *      mrel0;
-	uint_t *const mloc0 = umalloc(totrelsz>>1);
+	Elf_Rel *      mrelp;
-	uint_t *      mlocp = mloc0;
+
+	uint_t *      mloc0;
+	uint_t *      mlocp;
 
 	unsigned rel_entsize = 0;
 	unsigned symsec_sh_link = 0;
 
+	int result = 0;
+
+	totrelsz = tot_relsize(shdr0, nhdr, shstrtab, fname);
+	if (totrelsz == 0)
+		return 0;
+	mrel0 = umalloc(totrelsz);
+	mrelp = mrel0;
+	if (!mrel0)
+		return -1;
+
+	/* 2*sizeof(address) <= sizeof(Elf_Rel) */
+	mloc0 = umalloc(totrelsz>>1);
+	mlocp = mloc0;
+	if (!mloc0) {
+		free(mrel0);
+		return -1;
+	}
+
 	for (relhdr = shdr0, k = nhdr; k; --k, ++relhdr) {
 		char const *const txtname = has_rel_mcount(relhdr, shdr0,
 			shstrtab, fname);
+		if (txtname == already_has_rel_mcount) {
+			result = 0;
+			file_updated = 0;
+			goto out; /* Nothing to be done; don't append! */
+		}
 		if (txtname && is_mcounted_section_name(txtname)) {
+			unsigned int recsym;
 			uint_t recval = 0;
-			unsigned const recsym = find_secsym_ndx(
+
-				w(relhdr->sh_info), txtname, &recval,
+			symsec_sh_link = w(relhdr->sh_link);
-				&shdr0[symsec_sh_link = w(relhdr->sh_link)],
+			result = find_secsym_ndx(w(relhdr->sh_info), txtname,
-				ehdr);
+						&recval, &recsym,
+						&shdr0[symsec_sh_link],
+						ehdr);
+			if (result)
+				goto out;
 
 			rel_entsize = _w(relhdr->sh_entsize);
 			mlocp = sift_rel_mcount(mlocp,
@@ -543,13 +593,17 @@ do_func(Elf_Ehdr *const ehdr, char const *const fname, unsigned const reltype)
 			 * This section is ignored by ftrace, but still
 			 * has mcount calls. Convert them to nops now.
 			 */
-			nop_mcount(relhdr, ehdr, txtname);
+			if (nop_mcount(relhdr, ehdr, txtname) < 0) {
+				result = -1;
+				goto out;
+			}
 		}
 	}
-	if (mloc0 != mlocp) {
+	if (!result && mloc0 != mlocp)
-		append_func(ehdr, shstr, mloc0, mlocp, mrel0, mrelp,
+		result = append_func(ehdr, shstr, mloc0, mlocp, mrel0, mrelp,
-			    rel_entsize, symsec_sh_link);
+				     rel_entsize, symsec_sh_link);
-	}
+out:
 	free(mrel0);
 	free(mloc0);
+	return result;
 }

tools/testing/selftests/ftrace/test.d/functions

@@ -115,7 +115,7 @@ ftrace_errlog_check() { # err-prefix command-with-error-pos-by-^ command-file
     command=$(echo "$2" | tr -d ^)
     echo "Test command: $command"
     echo > error_log
-    (! echo "$command" > "$3" ) 2> /dev/null
+    (! echo "$command" >> "$3" ) 2> /dev/null
     grep "$1: error:" -A 3 error_log
     N=$(tail -n 1 error_log | wc -c)
     # "  Command: " and "^\n" => 13

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

@@ -24,7 +24,21 @@ test -d events/kprobes2/event2 || exit_failure
 
 :;: "Add an event on dot function without name" ;:
 
-FUNC=`grep -m 10 " [tT] .*\.isra\..*$" /proc/kallsyms | tail -n 1 | cut -f 3 -d " "`
+find_dot_func() {
+	if [ ! -f available_filter_functions ]; then
+		grep -m 10 " [tT] .*\.isra\..*$" /proc/kallsyms | tail -n 1 | cut -f 3 -d " "
+		return;
+	fi
+
+	grep " [tT] .*\.isra\..*" /proc/kallsyms | cut -f 3 -d " " | while read f; do
+		if grep -s $f available_filter_functions; then
+			echo $f
+			break
+		fi
+	done
+}
+
+FUNC=`find_dot_func | tail -n 1`
 [ "x" != "x$FUNC" ] || exit_unresolved
 echo "p $FUNC" > kprobe_events
 EVENT=`grep $FUNC kprobe_events | cut -f 1 -d " " | cut -f 2 -d:`

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

@@ -0,0 +1,35 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+# description: Create/delete multiprobe on kprobe event
+
+[ -f kprobe_events ] || exit_unsupported
+
+grep -q "Create/append/" README || exit_unsupported
+
+# Choose 2 symbols for target
+SYM1=_do_fork
+SYM2=do_exit
+EVENT_NAME=kprobes/testevent
+
+DEF1="p:$EVENT_NAME $SYM1"
+DEF2="p:$EVENT_NAME $SYM2"
+
+:;: "Define an event which has 2 probes" ;:
+echo $DEF1 >> kprobe_events
+echo $DEF2 >> kprobe_events
+cat kprobe_events | grep "$DEF1"
+cat kprobe_events | grep "$DEF2"
+
+:;: "Remove the event by name (should remove both)" ;:
+echo "-:$EVENT_NAME" >> kprobe_events
+test `cat kprobe_events | wc -l` -eq 0
+
+:;: "Remove just 1 event" ;:
+echo $DEF1 >> kprobe_events
+echo $DEF2 >> kprobe_events
+echo "-:$EVENT_NAME $SYM1" >> kprobe_events
+! cat kprobe_events | grep "$DEF1"
+cat kprobe_events | grep "$DEF2"
+
+:;: "Appending different type must fail" ;:
+! echo "$DEF1 \$stack" >> kprobe_events

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

@@ -41,6 +41,11 @@ check_error 'p vfs_read ^%none_reg'	# BAD_REG_NAME
 check_error 'p vfs_read ^@12345678abcde'	# BAD_MEM_ADDR
 check_error 'p vfs_read ^@+10'		# FILE_ON_KPROBE
 
+grep -q "imm-value" README && \
+check_error 'p vfs_read arg1=\^x'	# BAD_IMM
+grep -q "imm-string" README && \
+check_error 'p vfs_read arg1=\"abcd^'	# IMMSTR_NO_CLOSE
+
 check_error 'p vfs_read ^+0@0)'		# DEREF_NEED_BRACE
 check_error 'p vfs_read ^+0ab1(@0)'	# BAD_DEREF_OFFS
 check_error 'p vfs_read +0(+0(@0^)'	# DEREF_OPEN_BRACE
@@ -82,4 +87,15 @@ case $(uname -m) in
     ;;
 esac
 
+# multiprobe errors
+if grep -q "Create/append/" README && grep -q "imm-value" README; then
+echo 'p:kprobes/testevent _do_fork' > kprobe_events
+check_error '^r:kprobes/testevent do_exit'	# DIFF_PROBE_TYPE
+echo 'p:kprobes/testevent _do_fork abcd=\1' > kprobe_events
+check_error 'p:kprobes/testevent _do_fork ^bcd=\1'	# DIFF_ARG_TYPE
+check_error 'p:kprobes/testevent _do_fork ^abcd=\1:u8'	# DIFF_ARG_TYPE
+check_error 'p:kprobes/testevent _do_fork ^abcd=\"foo"'	# DIFF_ARG_TYPE
+check_error '^p:kprobes/testevent _do_fork'	# SAME_PROBE
+fi
+
 exit 0