Logging: fix crash when decoding a symbol that isn't a function

Saw this on my FreeBSD VM. The backtrace() function thought the nearest
symbol to something was "_ZTSNSt3__110__function6__baseIFbPvS2_EEE",
which decoded to

 typeinfo name for std::__1::__function::__base<bool (void*, void*)>

The function pointer type inside parameter threw the decoder for a loop
and caused it to crash with the failed assertion in qbytearray.h:

 inline char QByteArray::at(qsizetype i) const
 { Q_ASSERT(size_t(i) < size_t(size())); return d.data()[i]; }

I noticed this
 - because tst_qtimer hung
 - because qFormatLogMessage deadlocked acquiring QMessagePattern::mutex
 - because the logging recursed
 - because qCleanupFuncinfo failed an assertion while formatting the
   backtrace (my QT_MESSAGE_PATTERN has %{backtrace})
 - because QTimer::~QTimer -> QObject::killTimer printed a warning
 - because tst_QTimer::moveToThread produces warnings

Pick-to: 5.15 6.2 6.4 6.5
Change-Id: Ieec322d73c1e40ad95c8fffd17464f86e9725991
Reviewed-by: Kai Köhne <kai.koehne@qt.io>

1 files changed, 6 insertions, 0 deletions

diff --git a/src/corelib/global/qlogging.cpp b/src/corelib/global/qlogging.cpp
index e80e5b72d5..82e79e5e01 100644
--- a/src/corelib/global/qlogging.cpp
+++ b/src/corelib/global/qlogging.cpp
@@ -1021,6 +1021,12 @@ Q_AUTOTEST_EXPORT QByteArray qCleanupFuncinfo(QByteArray info)
             // Don't know how to parse this function name
             return info;
         }
+        if (info.indexOf('>', pos) != -1
+                || info.indexOf(':', pos) != -1) {
+            // that wasn't the function argument list.
+            pos = info.size();
+            break;
+        }
 
         // find the beginning of the argument list
         --pos;