Raise exceptions when blocked in bad FDs (fixes Trac #4934)

Before the patch any call to 'select()' with 'bad_fd' led to:
- unblocking of all threads
- hiding exception for 'threadWaitRead bad_fd'

The patch fixes both cases in this way:
after 'select()' failure we iterate over each blocked descriptor
and poll individually to see it's actual status, which is:
- READY (move to run queue)
- BLOCKED (leave in blocked queue)
- INVALID (send an IOErrror exception)

Signed-off-by: Sergei Trofimovich <slyfox@gentoo.org>

1 files changed, 1 insertions, 0 deletions

diff --git a/rts/RtsStartup.c b/rts/RtsStartup.c
index 06e888c1b2..c9f5880774 100644
--- a/rts/RtsStartup.c
+++ b/rts/RtsStartup.c
@@ -209,6 +209,7 @@ hs_init_ghc(int *argc, char **argv[], RtsConfig rts_config)
     getStablePtr((StgPtr)nonTermination_closure);
     getStablePtr((StgPtr)blockedIndefinitelyOnSTM_closure);
     getStablePtr((StgPtr)nestedAtomically_closure);
+    getStablePtr((StgPtr)blockedOnBadFD_closure);
 
     getStablePtr((StgPtr)runSparks_closure);
     getStablePtr((StgPtr)ensureIOManagerIsRunning_closure);