SERVER-49078 Disable libunwind for TSAN

5 files changed, 27 insertions, 16 deletions

diff --git a/SConstruct b/SConstruct
index e1dc9255b93..0f47acf5684 100644
--- a/SConstruct
+++ b/SConstruct
@@ -2917,6 +2917,20 @@ def doConfigure(myenv):
             myenv.AppendUnique(CPPDEFINES=['ADDRESS_SANITIZER'])
 
         if using_tsan:
+
+            if use_libunwind:
+                # TODO: SERVER-48622
+                #
+                # See https://github.com/google/sanitizers/issues/943
+                # for why we disallow combining TSAN with
+                # libunwind. We could, atlernatively, have added logic
+                # to automate the decision about whether to enable
+                # libunwind based on whether TSAN is enabled, but that
+                # logic is already complex, and it feels better to
+                # make it explicit that using TSAN means you won't get
+                # the benefits of libunwind. Fixing this is:
+                env.FatalError("Cannot use libunwind with TSAN, please add --use-libunwind=off to your compile flags")
+
             # die_after_fork=0 is a temporary setting to allow tests to continue while we figure out why
             # we're running afoul of it. If we remove it here, it also needs to be removed from the test
             # variant in etc/evergreen.yml
diff --git a/etc/evergreen.yml b/etc/evergreen.yml
index cc8d08ac676..f02812dcccc 100644
--- a/etc/evergreen.yml
+++ b/etc/evergreen.yml
@@ -12186,7 +12186,7 @@ buildvariants:
     # TODO: Remove some of the excluded tags when the Biggie storage engine is
     # further along in development: https://jira.mongodb.org/browse/SERVER-48325
     test_flags: --storageEngine=biggie --excludeWithAnyTags=requires_persistence,requires_journaling,uses_transactions,requires_wiredtiger,requires_snapshot_read
-    compile_flags: --variables-files=etc/scons/mongodbtoolchain_v3_clang.vars --dbg=on --opt=on --allocator=system --sanitize=thread --ssl --enable-free-mon=on -j$(grep -c ^processor /proc/cpuinfo)
+    compile_flags: --variables-files=etc/scons/mongodbtoolchain_v3_clang.vars --dbg=on --opt=on --allocator=system --sanitize=thread --ssl --enable-free-mon=on --use-libunwind=off -j$(grep -c ^processor /proc/cpuinfo)
     # Avoid starting too many mongod's under TSAN build.
     resmoke_jobs_factor: 0.3
     scons_cache_scope: shared
diff --git a/etc/tsan.suppressions b/etc/tsan.suppressions
index 08da28be651..f02173b5799 100644
--- a/etc/tsan.suppressions
+++ b/etc/tsan.suppressions
@@ -23,3 +23,4 @@ race:src/third_party/wiredtiger/*
 # handlers.
 signal:abruptQuitAction
 signal:abruptQuitWithAddrSignal
+signal:StackTraceSigAltStackTest::tryHandler
diff --git a/src/mongo/util/stacktrace.h b/src/mongo/util/stacktrace.h
index 4cc1ed688b6..e36a0aea03b 100644
--- a/src/mongo/util/stacktrace.h
+++ b/src/mongo/util/stacktrace.h
@@ -40,10 +40,6 @@
 #include "mongo/bson/bsonobj.h"
 #include "mongo/config.h"
 
-#if !defined(__has_feature)
-#define __has_feature(x) 0
-#endif
-
 /**
  * All-thread backtrace is only implemented on Linux. Even on Linux, it's only AS-safe
  * when we are using the libunwind backtrace implementation. The feature and related
@@ -51,20 +47,10 @@
  *    - setupStackTraceSignalAction
  *    - markAsStackTraceProcessingThread
  *    - printAllThreadStacks
- *
- *    This feature currently does not work with TSAN because TSAN introduces internal
- *    threads which block SIGUSR2, and that violates our assumption that all threads
- *    are known and accept SIGUSR2. With this enabled, users could try getting a
- *    stack trace and get a segfault instead. For the time being, we are disabling
- *    this feature with TSAN. However, this feature will need to be fixed to work with
- *    TSAN so developers can diagnose TSAN test failures with on-demand stack traces.
- *    TODO: https://jira.mongodb.org/browse/SERVER-48622
  */
-#if defined(__linux__)
-#if defined(MONGO_CONFIG_USE_LIBUNWIND) && !__has_feature(thread_sanitizer)
+#if defined(__linux__) && defined(MONGO_CONFIG_USE_LIBUNWIND)
 #define MONGO_STACKTRACE_CAN_DUMP_ALL_THREADS
 #endif
-#endif
 
 namespace mongo {
 
diff --git a/src/mongo/util/stacktrace_posix.cpp b/src/mongo/util/stacktrace_posix.cpp
index 3ad87711037..7b888f16c80 100644
--- a/src/mongo/util/stacktrace_posix.cpp
+++ b/src/mongo/util/stacktrace_posix.cpp
@@ -56,6 +56,16 @@
 #define MONGO_STACKTRACE_BACKEND_EXECINFO 2
 
 #if defined(MONGO_CONFIG_USE_LIBUNWIND)
+
+#if !defined(__has_feature)
+#define __has_feature(x) 0
+#endif
+
+#if __has_feature(thread_sanitizer)
+// TODO: SERVER-48622 (and see also https://github.com/google/sanitizers/issues/943)
+#error "Cannot currently use libunwind with -fsanitize=thread"
+#endif
+
 #define MONGO_STACKTRACE_BACKEND MONGO_STACKTRACE_BACKEND_LIBUNWIND
 #elif defined(MONGO_CONFIG_HAVE_EXECINFO_BACKTRACE)
 #define MONGO_STACKTRACE_BACKEND MONGO_STACKTRACE_BACKEND_EXECINFO