Merge pull request #13 from jean-edouard/x64_more_segv

ghc: add yet another segv fix

recipes-devtools/ghc/files/0009-Fix-segfault-in-retainer-profiling-when-using-multiple-cores-5909.patch

@@ -0,0 +1,56 @@
+From a5879a6c2412452fbda8c96e9d921c35279b9d9d Mon Sep 17 00:00:00 2001
+From: Simon Marlow <[email protected]>
+Date: Tue, 19 Feb 2013 09:58:31 +0000
+Subject: [PATCH] Fix segfault in retainer profiling when using multiple cores
+ (#5909)
+
+Thanks to @akio on the ticket for the diagnosis and the patch.  I
+modified the comments a bit.
+---
+ rts/sm/Evac.c | 17 +++++++++++++++--
+  1 file changed, 15 insertions(+), 2 deletions(-)
+
+--- a/rts/sm/Evac.c
++++ b/rts/sm/Evac.c
+@@ -33,7 +33,7 @@ StgWord64 whitehole_spin = 0;
+ #define HEAP_ALLOCED_GC(p) HEAP_ALLOCED(p)
+ #endif
+
+-#if !defined(PARALLEL_GC)
++#if !defined(PARALLEL_GC) || defined(PROFILING)
+ #define copy_tag_nolock(p, info, src, size, stp, tag) \
+         copy_tag(p, info, src, size, stp, tag)
+ #endif
+@@ -114,6 +114,17 @@ copy_tag(StgClosure **p, const StgInfoTa
+         const StgInfoTable *new_info;
+         new_info = (const StgInfoTable *)cas((StgPtr)&src->header.info, (W_)info, MK_FORWARDING_PTR(to));
+         if (new_info != info) {
++#ifdef PROFILING
++            // We copied this object at the same time as another
++            // thread.  We'll evacuate the object again and the copy
++            // we just made will be discarded at the next GC, but we
++            // may have copied it after the other thread called
++            // SET_EVACUAEE_FOR_LDV(), which would confuse the LDV
++            // profiler when it encounters this closure in
++            // processHeapClosureForDead.  So we reset the LDVW field
++            // here.
++            LDVW(to) = 0;
++#endif
+             return evacuate(p); // does the failed_to_evac stuff
+         } else {
+             *p = TAG_CLOSURE(tag,(StgClosure*)to);
+@@ -127,11 +138,13 @@ copy_tag(StgClosure **p, const StgInfoTa
+ #ifdef PROFILING
+     // We store the size of the just evacuated object in the LDV word so that
+     // the profiler can guess the position of the next object later.
++    // This is safe only if we are sure that no other thread evacuates
++    // the object again, so we cannot use copy_tag_nolock when PROFILING.
+     SET_EVACUAEE_FOR_LDV(from, size);
+ #endif
+ }
+
+-#if defined(PARALLEL_GC)
++#if defined(PARALLEL_GC) && !defined(PROFILING)
+ STATIC_INLINE void
+ copy_tag_nolock(StgClosure **p, const StgInfoTable *info, 
+          StgClosure *src, nat size, step *stp, StgWord tag)

recipes-devtools/ghc/ghc-6.12.3.inc

@@ -17,6 +17,7 @@ SRC_URI = " \
     file://0006-stdcall-x86-64.patch \
     file://0007-x64-more-stack.patch \
     file://0008-7919-large-objects.patch \
+    file://0009-Fix-segfault-in-retainer-profiling-when-using-multiple-cores-5909.patch \
 "
 SRC_URI[md5sum] = "4c2663c2eff833d7b9f39ef770eefbd6"
 SRC_URI[sha256sum] = "6cbdbe415011f2c7d15e4d850758d8d393f70617b88cb3237d2c602bb60e5e68"