commit e3d32ff805c917e6a8a6ed1c6e1acb1f2e83c544
author Frank Tang <ftang@chromium.org> Fri May 10 17:01:00 2019
committer Jungshik Shin <jshin@chromium.org> Sat May 11 04:59:16 2019
tree 6d822056d72b27b867ba3de3e151c9e16b31bde3
parent d65b27ff194fd75e3aa005a92d3619aebeec189e

Fix additional thread safety issue in timezone code

This is an update to the previous fix at
 https://chromium-review.googlesource.com/c/chromium/deps/icu/+/1602037

It takes care of threading issue in initDefault in timezone.cpp as well.

See
https://logs.chromium.org/logs/v8/buildbucket/cr-buildbucket.appspot.com/8913891060019594592/+/steps/Check/0/logs/DateCache.AdoptDefaultMixed/0

Upstream bug: https://unicode-org.atlassian.net/browse/ICU-20595
upstream PR: https://github.com/unicode-org/icu/pull/649/

Bug: chromium:950851
Test: v8 unittests - DateCache:AdoptDefault*
Change-Id: Ifc215e02992050af5c55e1cc0208cff61112c9ac
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/deps/icu/+/1604257
Reviewed-by: Jungshik Shin <jshin@chromium.org>

patches/timezone.patch

diff --git a/patches/timezone.patch b/patches/timezone.patch
index d456d6f..bf7e172 100644
--- a/patches/timezone.patch
+++ b/patches/timezone.patch
@@ -1,12 +1,12 @@
 diff --git a/source/i18n/timezone.cpp b/source/i18n/timezone.cpp
-index f129d8b6..f7b48273 100644
+index f129d8b6..32214d72 100644
 --- a/source/i18n/timezone.cpp
 +++ b/source/i18n/timezone.cpp
 @@ -527,6 +527,11 @@ TimeZone::detectHostTimeZone()
  
  // -------------------------------------
  
-+static UMutex *gMutex() {
++static UMutex *gDefaultZoneMutex() {
 +    static UMutex* m = new UMutex();
 +    return m;
 +}
@@ -18,31 +18,32 @@
  {
      ucln_i18n_registerCleanup(UCLN_I18N_TIMEZONE, timeZone_cleanup);
  
-+    Mutex lock(gMutex());
++    Mutex lock(gDefaultZoneMutex());
      // If setDefault() has already been called we can skip getting the
      // default zone information from the system.
      if (DEFAULT_ZONE != NULL) {
-@@ -571,7 +577,11 @@ TimeZone* U_EXPORT2
+@@ -571,7 +577,10 @@ TimeZone* U_EXPORT2
  TimeZone::createDefault()
  {
      umtx_initOnce(gDefaultZoneInitOnce, initDefault);
 -    return (DEFAULT_ZONE != NULL) ? DEFAULT_ZONE->clone() : NULL;
-+    if (DEFAULT_ZONE == NULL) return NULL;
 +    {
-+        Mutex lock(gMutex());
-+        return DEFAULT_ZONE->clone();
++        Mutex lock(gDefaultZoneMutex());
++        return (DEFAULT_ZONE != NULL) ? DEFAULT_ZONE->clone() : NULL;
 +    }
  }
  
  // -------------------------------------
-@@ -582,8 +592,11 @@ TimeZone::adoptDefault(TimeZone* zone)
+@@ -581,9 +590,12 @@ TimeZone::adoptDefault(TimeZone* zone)
+ {
      if (zone != NULL)
      {
-         TimeZone *old = DEFAULT_ZONE;
+-        TimeZone *old = DEFAULT_ZONE;
 -        DEFAULT_ZONE = zone;
 -        delete old;
 +        {
-+            Mutex lock(gMutex());
++            Mutex lock(gDefaultZoneMutex());
++            TimeZone *old = DEFAULT_ZONE;
 +            DEFAULT_ZONE = zone;
 +            delete old;
 +        }

source/i18n/timezone.cpp

diff --git a/source/i18n/timezone.cpp b/source/i18n/timezone.cpp
index f7b4827..129e6a5 100644
--- a/source/i18n/timezone.cpp
+++ b/source/i18n/timezone.cpp
@@ -527,7 +527,7 @@
 
 // -------------------------------------
 
-static UMutex *gMutex() {
+static UMutex *gDefaultZoneMutex() {
     static UMutex* m = new UMutex();
     return m;
 }
@@ -541,7 +541,7 @@
 {
     ucln_i18n_registerCleanup(UCLN_I18N_TIMEZONE, timeZone_cleanup);
 
-    Mutex lock(gMutex());
+    Mutex lock(gDefaultZoneMutex());
     // If setDefault() has already been called we can skip getting the
     // default zone information from the system.
     if (DEFAULT_ZONE != NULL) {
@@ -577,10 +577,9 @@
 TimeZone::createDefault()
 {
     umtx_initOnce(gDefaultZoneInitOnce, initDefault);
-    if (DEFAULT_ZONE == NULL) return NULL;
     {
-        Mutex lock(gMutex());
-        return DEFAULT_ZONE->clone();
+        Mutex lock(gDefaultZoneMutex());
+        return (DEFAULT_ZONE != NULL) ? DEFAULT_ZONE->clone() : NULL;
     }
 }
 
@@ -591,9 +590,9 @@
 {
     if (zone != NULL)
     {
-        TimeZone *old = DEFAULT_ZONE;
         {
-            Mutex lock(gMutex());
+            Mutex lock(gDefaultZoneMutex());
+            TimeZone *old = DEFAULT_ZONE;
             DEFAULT_ZONE = zone;
             delete old;
         }