From afabd52e95235ab36c5ad7b3473b5d6a4d58360b Mon Sep 17 00:00:00 2001 From: Simon Marlow Date: Tue, 10 Aug 2010 13:37:39 +0000 Subject: [PATCH] Run finalizers *after* updating the stable pointer table (#4221) Silly bug really, we were running the C finalizers while the StablePtr table was still in a partially-updated state during GC, but finalizers are allowed to call freeStablePtr() (via hs_free_fun_ptr(), for example), and chaos ensues. --- rts/sm/GC.c | 19 +++++++++++-------- 1 file changed, 11 insertions(+), 8 deletions(-) diff --git a/rts/sm/GC.c b/rts/sm/GC.c index ee3e170..18a87bd 100644 --- a/rts/sm/GC.c +++ b/rts/sm/GC.c @@ -727,11 +727,6 @@ SET_GCT(gc_threads[0]); // Reset the nursery resetNurseries(); - // start any pending finalizers - RELEASE_SM_LOCK; - scheduleFinalizers(cap, old_weak_ptr_list); - ACQUIRE_SM_LOCK; - // send exceptions to any threads which were about to die RELEASE_SM_LOCK; resurrectThreads(resurrected_threads); @@ -740,6 +735,17 @@ SET_GCT(gc_threads[0]); // Update the stable pointer hash table. updateStablePtrTable(major_gc); + // unlock the StablePtr table. Must be before scheduleFinalizers(), + // because a finalizer may call hs_free_fun_ptr() or + // hs_free_stable_ptr(), both of which access the StablePtr table. + stablePtrPostGC(); + + // Start any pending finalizers. Must be after + // updateStablePtrTable() and stablePtrPostGC() (see #4221). + RELEASE_SM_LOCK; + scheduleFinalizers(cap, old_weak_ptr_list); + ACQUIRE_SM_LOCK; + // check sanity after GC IF_DEBUG(sanity, checkSanity(rtsTrue)); @@ -771,9 +777,6 @@ SET_GCT(gc_threads[0]); slop = calcLiveBlocks() * BLOCK_SIZE_W - live; stat_endGC(allocated, live, copied, N, max_copied, avg_copied, slop); - // unlock the StablePtr table - stablePtrPostGC(); - // Guess which generation we'll collect *next* time initialise_N(force_major_gc); -- 1.7.10.4