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| author | Ben Gamari <bgamari.foss@gmail.com> | 2017-07-03 19:10:07 -0400 |
|---|---|---|
| committer | Ben Gamari <ben@smart-cactus.org> | 2017-07-03 19:42:22 -0400 |
| commit | fd7a7a6363d8dde1813bc23cb4ef00ebb70a49c0 (patch) | |
| tree | eab8f5e155dbe389bfc43d577dee38970474dded /rts/ThreadPaused.c | |
| parent | 0836bfbd480b00a690937060fc98df5e26453078 (diff) | |
| download | haskell-fd7a7a6363d8dde1813bc23cb4ef00ebb70a49c0.tar.gz | |
Eagerly blackhole AP_STACKs
This fixes #13615. See the rather lengthy Note [AP_STACKs must be
eagerly blackholed] for details.
Reviewers: simonmar, austin, erikd, dfeuer
Subscribers: duog, dfeuer, hsyl20, rwbarton, thomie
GHC Trac Issues: #13615
Differential Revision: https://phabricator.haskell.org/D3695
Diffstat (limited to 'rts/ThreadPaused.c')
| -rw-r--r-- | rts/ThreadPaused.c | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/rts/ThreadPaused.c b/rts/ThreadPaused.c index 2483466255..d01be291d3 100644 --- a/rts/ThreadPaused.c +++ b/rts/ThreadPaused.c @@ -275,6 +275,9 @@ threadPaused(Capability *cap, StgTSO *tso) // deadlocked on itself. See #5226 for an instance of // this bug. // + // Note that great care is required when entering computations + // suspended by this mechanism. See Note [AP_STACKs must be eagerly + // blackholed] for details. if (((bh_info == &stg_BLACKHOLE_info) && ((StgInd*)bh)->indirectee != (StgClosure*)tso) || (bh_info == &stg_WHITEHOLE_info)) @@ -303,6 +306,12 @@ threadPaused(Capability *cap, StgTSO *tso) continue; } + // We should never have made it here in the event of blackholes that + // we already own; they should have been marked when we blackholed + // them and consequently we should have stopped our stack walk + // above. + ASSERT(!((bh_info == &stg_BLACKHOLE_info) + && (((StgInd*)bh)->indirectee == (StgClosure*)tso))); // zero out the slop so that the sanity checker can tell // where the next closure is. |