[commit: ghc] ghc-7.6: rts: Ignore signal before deleting timer. Fixes #7303. (162b87d)

Repository : ssh://darcs.haskell.org//srv/darcs/ghc

On branch  : ghc-7.6

http://hackage.haskell.org/trac/ghc/changeset/162b87dfc610efa54ce3276e9a1e90b9dcb141a7

>---------------------------------------------------------------

commit 162b87dfc610efa54ce3276e9a1e90b9dcb141a7
Author: Erik de Castro Lopo <[email protected]>
Date:   Sat Oct 6 17:23:01 2012 +1000

    rts: Ignore signal before deleting timer. Fixes #7303.
    
    Was getting an ocassional hang or segfault when building GHC in a
    Qemu user space emulation of ARM. Turned out that the ITIMER_SIGNAL
    was being delivered *after* the call to timer_delete(). Setting the
    signal to SIG_IGN before deleting the timer solves the problem.

>---------------------------------------------------------------

 rts/posix/Itimer.c |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)

diff --git a/rts/posix/Itimer.c b/rts/posix/Itimer.c
index 8c9b1f8..80b3b56 100644
--- a/rts/posix/Itimer.c
+++ b/rts/posix/Itimer.c
@@ -204,6 +204,9 @@ void
 exitTicker (rtsBool wait STG_UNUSED)
 {
 #if defined(USE_TIMER_CREATE)
+    // Before deleting the timer set the signal to ignore to avoid the
+    // possibility of the signal being delivered after the timer is deleted.
+    signal(ITIMER_SIGNAL, SIG_IGN);
     timer_delete(timer);
     // ignore errors - we don't really care if it fails.
 #endif