X-Git-Url: https://git.lttng.org/?a=blobdiff_plain;f=src%2Flttng-syscalls.c;h=d618bd33ae02474338608cc429dcb06dd461c004;hb=7f52f0d4228ee23b783e907258835d2f818350d7;hp=2e8324133d53ed069ec325bd29fd958ca6360d28;hpb=c3fb484e598a4c08aa096901b611af7311ad77ca;p=lttng-modules.git

diff --git a/src/lttng-syscalls.c b/src/lttng-syscalls.c
index 2e832413..d618bd33 100644
--- a/src/lttng-syscalls.c
+++ b/src/lttng-syscalls.c
@@ -130,6 +130,15 @@ struct lttng_syscall_filter {
 	DECLARE_BITMAP(sc_exit, NR_syscalls);
 	DECLARE_BITMAP(sc_compat_entry, NR_compat_syscalls);
 	DECLARE_BITMAP(sc_compat_exit, NR_compat_syscalls);
+
+	/*
+	 * Reference counters keeping track of number of events enabled
+	 * for each bit.
+	 */
+	u32 sc_entry_refcount_map[NR_syscalls];
+	u32 sc_exit_refcount_map[NR_syscalls];
+	u32 sc_compat_entry_refcount_map[NR_compat_syscalls];
+	u32 sc_compat_exit_refcount_map[NR_compat_syscalls];
 };
 
 static void syscall_entry_event_unknown(struct hlist_head *unknown_action_list_head,
@@ -642,14 +651,15 @@ void lttng_syscall_event_enabler_create_matching_syscall_table_events(struct ltt
 	const struct lttng_kernel_event_desc *desc;
 	unsigned int i;
 
-	if (!IS_ENABLED(CONFIG_COMPAT) && (type == SC_TYPE_COMPAT_ENTRY || type == SC_TYPE_COMPAT_EXIT))
+#ifndef CONFIG_COMPAT
+	if (type == SC_TYPE_COMPAT_ENTRY || type == SC_TYPE_COMPAT_EXIT)
 		return;
-
+#endif
 	/* iterate over all syscall and create event that match */
 	for (i = 0; i < table_len; i++) {
 		struct lttng_kernel_event_common_private *event_priv;
 		struct hlist_head *head;
-		int found = 0;
+		bool found = false;
 
 		desc = table[i].desc;
 		if (!desc) {
@@ -665,8 +675,10 @@ void lttng_syscall_event_enabler_create_matching_syscall_table_events(struct ltt
 		 */
 		head = utils_borrow_hash_table_bucket(events_ht->table, LTTNG_EVENT_HT_SIZE, desc->event_name);
 		lttng_hlist_for_each_entry(event_priv, head, hlist_node) {
-			if (lttng_event_enabler_desc_match_event(syscall_event_enabler_common, desc, event_priv->pub))
-				found = 1;
+			if (lttng_event_enabler_desc_match_event(syscall_event_enabler_common, desc, event_priv->pub)) {
+				found = true;
+				break;
+			}
 		}
 		if (found)
 			continue;
@@ -700,9 +712,10 @@ void create_unknown_syscall_event(struct lttng_event_enabler_common *event_enabl
 	bool found = false;
 	struct hlist_head *head;
 
-	if (!IS_ENABLED(CONFIG_COMPAT) && (type == SC_TYPE_COMPAT_ENTRY || type == SC_TYPE_COMPAT_EXIT))
+#ifndef CONFIG_COMPAT
+	if (type == SC_TYPE_COMPAT_ENTRY || type == SC_TYPE_COMPAT_EXIT)
 		return;
-
+#endif
 	/*
 	 * Considering that currently system calls can only be enabled on a per
 	 * name basis (or wildcard based on a name), unknown syscall events are
@@ -741,8 +754,10 @@ void create_unknown_syscall_event(struct lttng_event_enabler_common *event_enabl
 	 */
 	head = utils_borrow_hash_table_bucket(events_ht->table, LTTNG_EVENT_HT_SIZE, desc->event_name);
 	lttng_hlist_for_each_entry(event_priv, head, hlist_node) {
-		if (lttng_event_enabler_desc_match_event(event_enabler, desc, event_priv->pub))
+		if (lttng_event_enabler_desc_match_event(event_enabler, desc, event_priv->pub)) {
 			found = true;
+			break;
+		}
 	}
 	if (!found)
 		lttng_syscall_event_enabler_create_event(event_enabler, desc, unknown_dispatch_list, type, -1U);
@@ -967,6 +982,7 @@ int lttng_syscall_filter_enable(
 {
 	const char *syscall_name;
 	unsigned long *bitmap;
+	u32 *refcount_map;
 	int syscall_nr;
 
 	syscall_name = get_syscall_name(desc_name, abi, entryexit);
@@ -989,9 +1005,11 @@ int lttng_syscall_filter_enable(
 		switch (abi) {
 		case LTTNG_SYSCALL_ABI_NATIVE:
 			bitmap = filter->sc_entry;
+			refcount_map = filter->sc_entry_refcount_map;
 			break;
 		case LTTNG_SYSCALL_ABI_COMPAT:
 			bitmap = filter->sc_compat_entry;
+			refcount_map = filter->sc_compat_entry_refcount_map;
 			break;
 		default:
 			return -EINVAL;
@@ -1001,9 +1019,11 @@ int lttng_syscall_filter_enable(
 		switch (abi) {
 		case LTTNG_SYSCALL_ABI_NATIVE:
 			bitmap = filter->sc_exit;
+			refcount_map = filter->sc_exit_refcount_map;
 			break;
 		case LTTNG_SYSCALL_ABI_COMPAT:
 			bitmap = filter->sc_compat_exit;
+			refcount_map = filter->sc_compat_exit_refcount_map;
 			break;
 		default:
 			return -EINVAL;
@@ -1012,9 +1032,10 @@ int lttng_syscall_filter_enable(
 	default:
 		return -EINVAL;
 	}
-	if (test_bit(syscall_nr, bitmap))
-		return -EEXIST;
-	bitmap_set(bitmap, syscall_nr, 1);
+	if (refcount_map[syscall_nr] == U32_MAX)
+		return -EOVERFLOW;
+	if (refcount_map[syscall_nr]++ == 0)
+		bitmap_set(bitmap, syscall_nr, 1);
 	return 0;
 }
 
@@ -1027,6 +1048,10 @@ int lttng_syscall_filter_enable_event(struct lttng_kernel_event_common *event)
 
 	WARN_ON_ONCE(event->priv->instrumentation != LTTNG_KERNEL_ABI_SYSCALL);
 
+	/* Skip unknown syscall */
+	if (syscall_id == -1U)
+		return 0;
+
 	ret = lttng_syscall_filter_enable(syscall_table->sc_filter,
 		event->priv->desc->event_name, event->priv->u.syscall.abi,
 		event->priv->u.syscall.entryexit);
@@ -1077,6 +1102,7 @@ int lttng_syscall_filter_disable(struct lttng_syscall_filter *filter,
 {
 	const char *syscall_name;
 	unsigned long *bitmap;
+	u32 *refcount_map;
 	int syscall_nr;
 
 	syscall_name = get_syscall_name(desc_name, abi, entryexit);
@@ -1099,9 +1125,11 @@ int lttng_syscall_filter_disable(struct lttng_syscall_filter *filter,
 		switch (abi) {
 		case LTTNG_SYSCALL_ABI_NATIVE:
 			bitmap = filter->sc_entry;
+			refcount_map = filter->sc_entry_refcount_map;
 			break;
 		case LTTNG_SYSCALL_ABI_COMPAT:
 			bitmap = filter->sc_compat_entry;
+			refcount_map = filter->sc_compat_entry_refcount_map;
 			break;
 		default:
 			return -EINVAL;
@@ -1111,9 +1139,11 @@ int lttng_syscall_filter_disable(struct lttng_syscall_filter *filter,
 		switch (abi) {
 		case LTTNG_SYSCALL_ABI_NATIVE:
 			bitmap = filter->sc_exit;
+			refcount_map = filter->sc_exit_refcount_map;
 			break;
 		case LTTNG_SYSCALL_ABI_COMPAT:
 			bitmap = filter->sc_compat_exit;
+			refcount_map = filter->sc_compat_exit_refcount_map;
 			break;
 		default:
 			return -EINVAL;
@@ -1122,18 +1152,23 @@ int lttng_syscall_filter_disable(struct lttng_syscall_filter *filter,
 	default:
 		return -EINVAL;
 	}
-	if (!test_bit(syscall_nr, bitmap))
-		return -EEXIST;
-	bitmap_clear(bitmap, syscall_nr, 1);
-
+	if (refcount_map[syscall_nr] == 0)
+		return -ENOENT;
+	if (--refcount_map[syscall_nr] == 0)
+		bitmap_clear(bitmap, syscall_nr, 1);
 	return 0;
 }
 
 int lttng_syscall_filter_disable_event(struct lttng_kernel_event_common *event)
 {
 	struct lttng_kernel_syscall_table *syscall_table = get_syscall_table_from_event(event);
+	unsigned int syscall_id = event->priv->u.syscall.syscall_id;
 	int ret;
 
+	/* Skip unknown syscall */
+	if (syscall_id == -1U)
+		return 0;
+
 	ret = lttng_syscall_filter_disable(syscall_table->sc_filter,
 		event->priv->desc->event_name, event->priv->u.syscall.abi,
 		event->priv->u.syscall.entryexit);