[RFC PATCH perf/core 08/13] perf probe: Check kprobe blacklist in converting phase

[Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>]

Instead of checking kprobe blacklist in writing phase, check it
in converting phase.

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
---
 tools/perf/util/probe-event.c |   92 ++++++++++++++++++++++++-----------------
 1 file changed, 54 insertions(+), 38 deletions(-)

diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index 6c5ddb8..e8c3a25 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -549,6 +549,8 @@ static int add_module_to_probe_trace_events(struct probe_trace_event *tevs,
 	return ret;
 }
 
+static bool kprobe_blacklist__listed(unsigned long address);
+
 /* Post processing the probe events */
 static int post_process_probe_trace_events(struct probe_trace_event *tevs,
 					   int ntevs, const char *module,
@@ -575,27 +577,32 @@ static int post_process_probe_trace_events(struct probe_trace_event *tevs,
 	etext_addr = kernel_get_symbol_address_by_name("_etext", false);
 
 	for (i = 0; i < ntevs; i++) {
-		if (tevs[i].point.address && !tevs[i].point.retprobe) {
-			/* If we found a wrong one, mark it by NULL symbol */
-			if (etext_addr < tevs[i].point.address) {
-				pr_warning("%s+%lu is out of .text, skip it.\n",
-				   tevs[i].point.symbol, tevs[i].point.offset);
-				tmp = NULL;
-				skipped++;
-			} else {
-				tmp = strdup(reloc_sym->name);
-				if (!tmp)
-					return -ENOMEM;
-			}
-			/* If we have no realname, use symbol for it */
-			if (!tevs[i].point.realname)
-				tevs[i].point.realname = tevs[i].point.symbol;
-			else
-				free(tevs[i].point.symbol);
-			tevs[i].point.symbol = tmp;
-			tevs[i].point.offset = tevs[i].point.address -
-					       reloc_sym->unrelocated_addr;
+		if (!tevs[i].point.address || tevs[i].point.retprobe)
+			continue;
+		/* If we found a wrong one, mark it by NULL symbol */
+		if (etext_addr < tevs[i].point.address) {
+			pr_warning("%s+%lu is out of .text, skip it.\n",
+			   tevs[i].point.symbol, tevs[i].point.offset);
+			tmp = NULL;
+			skipped++;
+		} else if (kprobe_blacklist__listed(tevs[i].point.address)) {
+			pr_warning("%s is blacklisted function, skip it.\n",
+				   tevs[i].point.symbol);
+			tmp = NULL;
+			skipped++;
+		} else {
+			tmp = strdup(reloc_sym->name);
+			if (!tmp)
+				return -ENOMEM;
 		}
+		/* If we have no realname, use symbol for it */
+		if (!tevs[i].point.realname)
+			tevs[i].point.realname = tevs[i].point.symbol;
+		else
+			free(tevs[i].point.symbol);
+		tevs[i].point.symbol = tmp;
+		tevs[i].point.offset = tevs[i].point.address -
+				       reloc_sym->unrelocated_addr;
 	}
 	return skipped;
 }
@@ -2008,6 +2015,27 @@ kprobe_blacklist__find_by_address(struct list_head *blacklist,
 	return NULL;
 }
 
+static LIST_HEAD(kprobe_blacklist);
+
+static void kprobe_blacklist__init(void)
+{
+	if (!list_empty(&kprobe_blacklist))
+		return;
+
+	if (kprobe_blacklist__load(&kprobe_blacklist) < 0)
+		pr_debug("No kprobe blacklist support, ignored\n");
+}
+
+static void kprobe_blacklist__release(void)
+{
+	kprobe_blacklist__delete(&kprobe_blacklist);
+}
+
+static bool kprobe_blacklist__listed(unsigned long address)
+{
+	return !!kprobe_blacklist__find_by_address(&kprobe_blacklist, address);
+}
+
 /* Show an event */
 static int show_perf_probe_event(const char *group, const char *event,
 				 struct perf_probe_event *pev,
@@ -2236,8 +2264,6 @@ static int __add_probe_trace_events(struct perf_probe_event *pev,
 	int i, fd, ret;
 	struct probe_trace_event *tev = NULL;
 	struct strlist *namelist;
-	LIST_HEAD(blacklist);
-	struct kprobe_blacklist_node *node;
 
 	fd = probe_file__open(PF_FL_RW | (pev->uprobes ? PF_FL_UPROBE : 0));
 	if (fd < 0)
@@ -2251,27 +2277,13 @@ static int __add_probe_trace_events(struct perf_probe_event *pev,
 		goto close_out;
 	}
 
-	/* Get kprobe blacklist if exists */
-	if (!pev->uprobes) {
-		ret = kprobe_blacklist__load(&blacklist);
-		if (ret < 0)
-			pr_debug("No kprobe blacklist support, ignored\n");
-	}
-
 	ret = 0;
 	pr_info("Added new event%s\n", (ntevs > 1) ? "s:" : ":");
 	for (i = 0; i < ntevs; i++) {
 		tev = &tevs[i];
-		/* Skip if the symbol is out of .text (marked previously) */
+		/* Skip if the symbol is out of .text or blacklisted */
 		if (!tev->point.symbol)
 			continue;
-		/* Ensure that the address is NOT blacklisted */
-		node = kprobe_blacklist__find_by_address(&blacklist,
-							 tev->point.address);
-		if (node) {
-			pr_warning("Warning: Skipped probing on blacklisted function: %s\n", node->symbol);
-			continue;
-		}
 
 		/* Set new name for tev (and update namelist) */
 		ret = probe_trace_event__set_name(tev, pev, namelist,
@@ -2305,7 +2317,6 @@ static int __add_probe_trace_events(struct perf_probe_event *pev,
 			 tev->event);
 	}
 
-	kprobe_blacklist__delete(&blacklist);
 	strlist__delete(namelist);
 close_out:
 	close(fd);
@@ -2513,6 +2524,9 @@ int add_perf_probe_events(struct perf_probe_event *pevs, int npevs)
 	/* Loop 1: convert all events */
 	for (i = 0; i < npevs; i++) {
 		pkgs[i].pev = &pevs[i];
+		/* Init kprobe blacklist if needed */
+		if (!pkgs[i].pev->uprobes)
+			kprobe_blacklist__init();
 		/* Convert with or without debuginfo */
 		ret  = convert_to_probe_trace_events(pkgs[i].pev,
 						     &pkgs[i].tevs);
@@ -2520,6 +2534,8 @@ int add_perf_probe_events(struct perf_probe_event *pevs, int npevs)
 			goto end;
 		pkgs[i].ntevs = ret;
 	}
+	/* This just release blacklist only if allocated */
+	kprobe_blacklist__release();
 
 	/* Loop 2: add all events */
 	for (i = 0; i < npevs; i++) {