rts: Forcibly flush eventlog on barf

Previously we would attempt to flush via `endEventLogging` which can
easily deadlock, e.g., if `barf` fails during GC.

Using `flushEventLog` directly may result in slightly less consistent
eventlog output (since we don't take all capabilities before flushing)
but avoids deadlocking.

1 files changed, 6 insertions, 1 deletions

diff --git a/rts/RtsMessages.c b/rts/RtsMessages.c
index 507d007484..d760bd233c 100644
--- a/rts/RtsMessages.c
+++ b/rts/RtsMessages.c
@@ -186,7 +186,12 @@ rtsFatalInternalErrorFn(const char *s, va_list ap)
 #endif
 
 #if defined(TRACING)
-  if (RtsFlags.TraceFlags.tracing == TRACE_EVENTLOG) endEventLogging();
+  if (RtsFlags.TraceFlags.tracing == TRACE_EVENTLOG) {
+    // Use flushAllCapsEventsBufs rather than endEventLogging here since
+    // the latter insists on acquiring all capabilities to flush the eventlog;
+    // this would deadlock if we barfed during a GC.
+    flushAllCapsEventsBufs();
+  }
 #endif
 
   abort();