Author: gclayton
Date: Tue Nov 3 16:42:04 2015
New Revision: 252005
URL: http://llvm.org/viewvc/llvm-project?rev=252005&view=rev
Log:
Fix a deadlock when connecting to a remote GDB server that might not support
all packets that lldb-server or debugserver supports. The issue was the
m_last_stop_packet_mutex mutex was being held by another thread and it was
deadlocking getting the thread list. We now try to lock the
m_last_stop_packet_mutex, and only continue if we successfully lock it. Else we
fall back to qfThreadInfo/qsThreadInfo.
<rdar://problem/22140023>
Modified:
lldb/trunk/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp
Modified: lldb/trunk/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp
URL:
http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp?rev=252005&r1=252004&r2=252005&view=diff
==============================================================================
--- lldb/trunk/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp (original)
+++ lldb/trunk/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp Tue Nov
3 16:42:04 2015
@@ -1832,25 +1832,29 @@ ProcessGDBRemote::UpdateThreadIDList ()
// that might contain a "threads" key/value pair
// Lock the thread stack while we access it
- Mutex::Locker stop_stack_lock(m_last_stop_packet_mutex);
- // Get the number of stop packets on the stack
- int nItems = m_stop_packet_stack.size();
- // Iterate over them
- for (int i = 0; i < nItems; i++)
+ //Mutex::Locker stop_stack_lock(m_last_stop_packet_mutex);
+ Mutex::Locker stop_stack_lock;
+ if (stop_stack_lock.TryLock(m_last_stop_packet_mutex))
{
- // Get the thread stop info
- StringExtractorGDBRemote &stop_info = m_stop_packet_stack[i];
- const std::string &stop_info_str = stop_info.GetStringRef();
- const size_t threads_pos = stop_info_str.find(";threads:");
- if (threads_pos != std::string::npos)
+ // Get the number of stop packets on the stack
+ int nItems = m_stop_packet_stack.size();
+ // Iterate over them
+ for (int i = 0; i < nItems; i++)
{
- const size_t start = threads_pos + strlen(";threads:");
- const size_t end = stop_info_str.find(';', start);
- if (end != std::string::npos)
+ // Get the thread stop info
+ StringExtractorGDBRemote &stop_info = m_stop_packet_stack[i];
+ const std::string &stop_info_str = stop_info.GetStringRef();
+ const size_t threads_pos = stop_info_str.find(";threads:");
+ if (threads_pos != std::string::npos)
{
- std::string value = stop_info_str.substr(start, end -
start);
- if (UpdateThreadIDsFromStopReplyThreadsValue(value))
- return true;
+ const size_t start = threads_pos + strlen(";threads:");
+ const size_t end = stop_info_str.find(';', start);
+ if (end != std::string::npos)
+ {
+ std::string value = stop_info_str.substr(start, end -
start);
+ if (UpdateThreadIDsFromStopReplyThreadsValue(value))
+ return true;
+ }
}
}
}
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