Fix group stop signal handling issue on Linux.
This patch addresses a bug where in a multi-threaded program a new
signal from the inferior may be received before all group-stop
messages from an earlier signal have been handled.
Patch by Andrew MacPherson
llvm-svn: 200226
diff --git a/lldb/source/Plugins/Process/Linux/ProcessMonitor.cpp b/lldb/source/Plugins/Process/Linux/ProcessMonitor.cpp
index 98dd9df..51d0d94 100644
--- a/lldb/source/Plugins/Process/Linux/ProcessMonitor.cpp
+++ b/lldb/source/Plugins/Process/Linux/ProcessMonitor.cpp
@@ -1798,14 +1798,23 @@
int ptrace_err;
if (!GetSignalInfo(wait_pid, &info, ptrace_err))
{
- if (log)
+ // another signal causing a StopAllThreads may have been received
+ // before wait_pid's group-stop was processed, handle it now
+ if (ptrace_err == EINVAL)
{
- log->Printf ("ProcessMonitor::%s() GetSignalInfo failed.", __FUNCTION__);
+ assert(WIFSTOPPED(status) && WSTOPSIG(status) == SIGSTOP);
- // This would be a particularly interesting case
- if (ptrace_err == EINVAL)
- log->Printf ("ProcessMonitor::%s() in group-stop", __FUNCTION__);
+ if (log)
+ log->Printf ("ProcessMonitor::%s() resuming from group-stop", __FUNCTION__);
+ // inferior process is in 'group-stop', so deliver SIGSTOP signal
+ if (!Resume(wait_pid, SIGSTOP)) {
+ assert(0 && "SIGSTOP delivery failed while in 'group-stop' state");
+ }
+ continue;
}
+
+ if (log)
+ log->Printf ("ProcessMonitor::%s() GetSignalInfo failed.", __FUNCTION__);
return false;
}