From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Date: Thu, 1 Mar 2012 17:13:47 +0000 (-0500)
Subject: Fix: fixup vtid TLS
X-Git-Tag: v2.1.0-rc1~97^2~5
X-Git-Url: https://git.lttng.org./?a=commitdiff_plain;h=daeb93bb244bf406d9e8bd620247b64f9144127a;p=lttng-ust.git

Fix: fixup vtid TLS

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
---

diff --git a/liblttng-ust/ltt-tracer-core.h b/liblttng-ust/ltt-tracer-core.h
index 7fdf3c9e..2ea4eadf 100644
--- a/liblttng-ust/ltt-tracer-core.h
+++ b/liblttng-ust/ltt-tracer-core.h
@@ -38,5 +38,6 @@ void ust_lock(void);
 void ust_unlock(void);
 
 void lttng_fixup_event_tls(void);
+void lttng_fixup_vtid_tls(void);
 
 #endif /* _LTT_TRACER_CORE_H */
diff --git a/liblttng-ust/lttng-context-vtid.c b/liblttng-ust/lttng-context-vtid.c
index 3fe86405..c419d18b 100644
--- a/liblttng-ust/lttng-context-vtid.c
+++ b/liblttng-ust/lttng-context-vtid.c
@@ -13,6 +13,7 @@
 #include <lttng/ust-tracer.h>
 #include <lttng/ringbuffer-config.h>
 #include <lttng/ust-tid.h>
+#include "ltt-tracer-core.h"
 
 /*
  * We cache the result to ensure we don't trigger a system call for
@@ -74,3 +75,11 @@ int lttng_add_vtid_to_ctx(struct lttng_ctx **ctx)
 	field->record = vtid_record;
 	return 0;
 }
+
+/*
+ * Force a read (imply TLS fixup for dlopen) of TLS variables.
+ */
+void lttng_fixup_vtid_tls(void)
+{
+	asm volatile ("" : : "m" (cached_vtid));
+}
diff --git a/liblttng-ust/lttng-ust-comm.c b/liblttng-ust/lttng-ust-comm.c
index 2f2c783b..1815801a 100644
--- a/liblttng-ust/lttng-ust-comm.c
+++ b/liblttng-ust/lttng-ust-comm.c
@@ -835,6 +835,7 @@ void __attribute__((constructor)) lttng_ust_init(void)
 	 */
 	lttng_fixup_event_tls();
 	lttng_fixup_ringbuffer_tls();
+	lttng_fixup_vtid_tls();
 
 	/*
 	 * We want precise control over the order in which we construct