From 4ae3f13373ab43824ddca62d3482584a6296641d Mon Sep 17 00:00:00 2001
From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Date: Thu, 9 Apr 2020 11:29:18 -0400
Subject: [PATCH] Fix: namespace contexts !CONFIG_RCU_TLS variable
 initialization

The namespace contexts introduced in lttng-ust 2.12 require to
initialize TLS variable to nonzero values. However, in !CONFIG_RCU_TLS
(compatibility mode using pthread setspecific), this initialization
does not build.

Use the new DEFINE_URCU_TLS_INIT from liburcu when building
!CONFIG_RCU_TLS to fix this issue. Since this requires a dependency on
a new liburcu version, only !CONFIG_RCU_TLS adds this dependency in the
fix. A followup cleanup patch will use DEFINE_URCU_TLS_INIT as we add
a strict version dependency.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
---
 liblttng-ust/lttng-context-cgroup-ns.c | 4 ++++
 liblttng-ust/lttng-context-ipc-ns.c    | 5 ++++-
 liblttng-ust/lttng-context-net-ns.c    | 5 ++++-
 liblttng-ust/lttng-context-uts-ns.c    | 4 ++++
 4 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/liblttng-ust/lttng-context-cgroup-ns.c b/liblttng-ust/lttng-context-cgroup-ns.c
index d4053150..97af2759 100644
--- a/liblttng-ust/lttng-context-cgroup-ns.c
+++ b/liblttng-ust/lttng-context-cgroup-ns.c
@@ -38,7 +38,11 @@
  * We cache the result to ensure we don't stat(2) the proc filesystem on
  * each event.
  */
+#ifdef CONFIG_RCU_TLS
 static DEFINE_URCU_TLS(ino_t, cached_cgroup_ns) = NS_INO_UNINITIALIZED;
+#else
+static DEFINE_URCU_TLS_INIT(ino_t, cached_cgroup_ns, NS_INO_UNINITIALIZED);
+#endif
 
 static
 ino_t get_cgroup_ns(void)
diff --git a/liblttng-ust/lttng-context-ipc-ns.c b/liblttng-ust/lttng-context-ipc-ns.c
index c973dc86..a05a6c61 100644
--- a/liblttng-ust/lttng-context-ipc-ns.c
+++ b/liblttng-ust/lttng-context-ipc-ns.c
@@ -33,12 +33,15 @@
 #include "lttng-tracer-core.h"
 #include "ns.h"
 
-
 /*
  * We cache the result to ensure we don't stat(2) the proc filesystem on
  * each event.
  */
+#ifdef CONFIG_RCU_TLS
 static DEFINE_URCU_TLS(ino_t, cached_ipc_ns) = NS_INO_UNINITIALIZED;
+#else
+static DEFINE_URCU_TLS_INIT(ino_t, cached_ipc_ns, NS_INO_UNINITIALIZED);
+#endif
 
 static
 ino_t get_ipc_ns(void)
diff --git a/liblttng-ust/lttng-context-net-ns.c b/liblttng-ust/lttng-context-net-ns.c
index 9d6ded12..c0aaa9d4 100644
--- a/liblttng-ust/lttng-context-net-ns.c
+++ b/liblttng-ust/lttng-context-net-ns.c
@@ -33,12 +33,15 @@
 #include "lttng-tracer-core.h"
 #include "ns.h"
 
-
 /*
  * We cache the result to ensure we don't stat(2) the proc filesystem on
  * each event.
  */
+#ifdef CONFIG_RCU_TLS
 static DEFINE_URCU_TLS(ino_t, cached_net_ns) = NS_INO_UNINITIALIZED;
+#else
+static DEFINE_URCU_TLS_INIT(ino_t, cached_net_ns, NS_INO_UNINITIALIZED);
+#endif
 
 static
 ino_t get_net_ns(void)
diff --git a/liblttng-ust/lttng-context-uts-ns.c b/liblttng-ust/lttng-context-uts-ns.c
index fb2d89f9..778ccb46 100644
--- a/liblttng-ust/lttng-context-uts-ns.c
+++ b/liblttng-ust/lttng-context-uts-ns.c
@@ -38,7 +38,11 @@
  * We cache the result to ensure we don't stat(2) the proc filesystem on
  * each event.
  */
+#ifdef CONFIG_RCU_TLS
 static DEFINE_URCU_TLS(ino_t, cached_uts_ns) = NS_INO_UNINITIALIZED;
+#else
+static DEFINE_URCU_TLS_INIT(ino_t, cached_uts_ns, NS_INO_UNINITIALIZED);
+#endif
 
 static
 ino_t get_uts_ns(void)
-- 
2.25.1