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| author | Ben Gamari <ben@smart-cactus.org> | 2019-06-24 15:37:12 -0400 |
|---|---|---|
| committer | Andreas Klebinger <klebinger.andreas@gmx.at> | 2021-08-03 12:08:57 +0000 |
| commit | f29d897a344095299580beea94c227286f07c92b (patch) | |
| tree | 4ec1c7b6e18e1a47c428e65db8487a4afaae3c27 | |
| parent | 34e352173dd1fc3cd86c49380fda5a4eb5dd7aef (diff) | |
| download | haskell-wip/clear-bdescr-free.tar.gz | |
rts: Clear bd->free in the DEBUG RTSwip/clear-bdescr-free
In the non-DEBUG RTS we initialize `bd->free` lazily (e.g. when
the mutator starts allocating into the block in stg_gc_noregs).
However, in the past we have had bugs where code looked at
the `free` field of blocks that the mutator never allocated into.
We set the free pointer to NULL to catch this.
This would help to catch #16862.
| -rw-r--r-- | includes/rts/storage/Block.h | 5 | ||||
| -rw-r--r-- | rts/sm/Storage.c | 8 | ||||
| -rwxr-xr-x[-rw-r--r--] | testsuite/tests/rts/flags/T20006.hs | 0 |
3 files changed, 13 insertions, 0 deletions
diff --git a/includes/rts/storage/Block.h b/includes/rts/storage/Block.h index 626cddb2a2..a1db4edadd 100644 --- a/includes/rts/storage/Block.h +++ b/includes/rts/storage/Block.h @@ -107,6 +107,11 @@ typedef struct bdescr_ { // value (StgPtr)(-1) is used to // indicate that a block is unallocated. // + // Also note that this field is only set lazily + // (e.g. when the mutator starts and stops + // allocating in the nursery stg_gc_noregs) in + // the case of a nursery block. + // // Unused by the non-moving allocator. struct NonmovingSegmentInfo nonmoving_segment; }; diff --git a/rts/sm/Storage.c b/rts/sm/Storage.c index 7d450a8931..b29c734f81 100644 --- a/rts/sm/Storage.c +++ b/rts/sm/Storage.c @@ -828,6 +828,14 @@ resetNurseries (void) ASSERT(bd->gen == g0); ASSERT(bd->node == capNoToNumaNode(n)); IF_DEBUG(zero_on_gc, memset(bd->start, 0xaa, BLOCK_SIZE)); + + // In the non-DEBUG RTS we initialize bd->free lazily (e.g. when + // the mutator starts allocating into the block in stg_gc_noregs). + // However, in the past we have had bugs (e.g. #16862) where code + // looked at the ->free field of blocks that the mutator never + // allocated into. We set the free pointer to a dummy value + // (0xaaaaa...) to catch this. + IF_DEBUG(sanity, memset(&bd->free, 0xaa, sizeof(bd->free))); } } #endif diff --git a/testsuite/tests/rts/flags/T20006.hs b/testsuite/tests/rts/flags/T20006.hs index d82a4bd93b..d82a4bd93b 100644..100755 --- a/testsuite/tests/rts/flags/T20006.hs +++ b/testsuite/tests/rts/flags/T20006.hs |