X-Git-Url: https://git.liburcu.org/?a=blobdiff_plain;f=src%2Fbin%2Flttng-sessiond%2Flttng-syscall.cpp;h=821bbaa34f80b6e1c6d572192909c0ec0257aab2;hb=56047f5a23df5c2c583a102b8015bbec5a7da9f1;hp=3f09090cb37a6821fe61e6a1de68e3a049c46467;hpb=28ab034a2c3582d07d3423d2d746731f87d3969f;p=lttng-tools.git

diff --git a/src/bin/lttng-sessiond/lttng-syscall.cpp b/src/bin/lttng-sessiond/lttng-syscall.cpp
index 3f09090cb..821bbaa34 100644
--- a/src/bin/lttng-sessiond/lttng-syscall.cpp
+++ b/src/bin/lttng-sessiond/lttng-syscall.cpp
@@ -13,6 +13,7 @@
 
 #include <common/common.hpp>
 #include <common/kernel-ctl/kernel-ctl.hpp>
+#include <common/urcu.hpp>
 
 #include <stdbool.h>
 
@@ -85,7 +86,7 @@ int syscall_init_table(int tracer_fd)
 				/* Overflow, stop everything, something went really wrong. */
 				ERR("Syscall listing memory size overflow. Stopping");
 				free(syscall_table);
-				syscall_table = NULL;
+				syscall_table = nullptr;
 				ret = -EINVAL;
 				goto error;
 			}
@@ -110,7 +111,7 @@ int syscall_init_table(int tracer_fd)
 			    syscall_table[index].name, name, sizeof(syscall_table[index].name))) {
 			ret = -EINVAL;
 			free(syscall_table);
-			syscall_table = NULL;
+			syscall_table = nullptr;
 			goto error;
 		}
 		/*
@@ -150,28 +151,31 @@ error_ioctl:
  * syscall hashtable used to track duplicate between 32 and 64 bit arch.
  *
  * This empty the hash table and destroys it after. After this, the pointer is
- * unsuable. RCU read side lock MUST be acquired before calling this.
+ * unsuable. RCU read side lock MUST NOT be acquired before calling this.
  */
 static void destroy_syscall_ht(struct lttng_ht *ht)
 {
 	struct lttng_ht_iter iter;
 	struct syscall *ksyscall;
 
-	ASSERT_RCU_READ_LOCKED();
-
 	DBG3("Destroying syscall hash table.");
 
 	if (!ht) {
 		return;
 	}
 
-	cds_lfht_for_each_entry (ht->ht, &iter.iter, ksyscall, node.node) {
-		int ret;
+	{
+		lttng::urcu::read_lock_guard read_lock;
+
+		cds_lfht_for_each_entry (ht->ht, &iter.iter, ksyscall, node.node) {
+			int ret;
 
-		ret = lttng_ht_del(ht, &iter);
-		LTTNG_ASSERT(!ret);
-		free(ksyscall);
+			ret = lttng_ht_del(ht, &iter);
+			LTTNG_ASSERT(!ret);
+			free(ksyscall);
+		}
 	}
+
 	lttng_ht_destroy(ht);
 }
 
@@ -197,13 +201,15 @@ static int init_syscall_ht(struct lttng_ht **ht)
 /*
  * Lookup a syscall in the given hash table by name.
  *
+ * RCU read lock MUST be acquired by the callers of this function.
+ *
  * Return syscall object if found or else NULL.
  */
 static struct syscall *lookup_syscall(struct lttng_ht *ht, const char *name)
 {
 	struct lttng_ht_node_str *node;
 	struct lttng_ht_iter iter;
-	struct syscall *ksyscall = NULL;
+	struct syscall *ksyscall = nullptr;
 
 	LTTNG_ASSERT(ht);
 	LTTNG_ASSERT(name);
@@ -277,14 +283,12 @@ ssize_t syscall_table_list(struct lttng_event **_events)
 	ssize_t ret;
 	struct lttng_event *events;
 	/* Hash table used to filter duplicate out. */
-	struct lttng_ht *syscalls_ht = NULL;
+	struct lttng_ht *syscalls_ht = nullptr;
 
 	LTTNG_ASSERT(_events);
 
 	DBG("Syscall table listing.");
 
-	rcu_read_lock();
-
 	/*
 	 * Allocate at least the number of total syscall we have even if some of
 	 * them might not be valid. The count below will make sure to return the
@@ -303,17 +307,20 @@ ssize_t syscall_table_list(struct lttng_event **_events)
 	}
 
 	for (i = 0; i < syscall_table_nb_entry; i++) {
-		struct syscall *ksyscall;
-
 		/* Skip empty syscalls. */
 		if (*syscall_table[i].name == '\0') {
 			continue;
 		}
 
-		ksyscall = lookup_syscall(syscalls_ht, syscall_table[i].name);
-		if (ksyscall) {
-			update_event_syscall_bitness(events, i, ksyscall->index);
-			continue;
+		{
+			lttng::urcu::read_lock_guard read_lock;
+			struct syscall *ksyscall;
+
+			ksyscall = lookup_syscall(syscalls_ht, syscall_table[i].name);
+			if (ksyscall) {
+				update_event_syscall_bitness(events, i, ksyscall->index);
+				continue;
+			}
 		}
 
 		ret = add_syscall_to_ht(syscalls_ht, i, index);
@@ -332,12 +339,10 @@ ssize_t syscall_table_list(struct lttng_event **_events)
 
 	destroy_syscall_ht(syscalls_ht);
 	*_events = events;
-	rcu_read_unlock();
 	return index;
 
 error:
 	destroy_syscall_ht(syscalls_ht);
 	free(events);
-	rcu_read_unlock();
 	return ret;
 }