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| author | Viktor Dukhovni <ietf-dane@dukhovni.org> | 2020-11-14 17:50:26 -0800 |
|---|---|---|
| committer | Marge Bot <ben+marge-bot@smart-cactus.org> | 2020-11-30 19:48:17 -0500 |
| commit | ab334262a605b0ebc228096d8af88a55aa5ea6b8 (patch) | |
| tree | b008a32494a42a5d2cb3b6c81996abfb10c26a2e | |
| parent | 6af074cecdee533791943af1191541f82abc34c4 (diff) | |
| download | haskell-ab334262a605b0ebc228096d8af88a55aa5ea6b8.tar.gz | |
dirty MVAR after mutating TSO queue head
While the original head and tail of the TSO queue may be in the same
generation as the MVAR, interior elements of the queue could be younger
after a GC run and may then be exposed by putMVar operation that updates
the queue head.
Resolves #18919
| -rw-r--r-- | rts/PrimOps.cmm | 30 | ||||
| -rw-r--r-- | rts/Threads.c | 13 |
2 files changed, 28 insertions, 15 deletions
diff --git a/rts/PrimOps.cmm b/rts/PrimOps.cmm index 7767ead2d8..a6b60ae1cc 100644 --- a/rts/PrimOps.cmm +++ b/rts/PrimOps.cmm @@ -1827,9 +1827,16 @@ loop: // There are readMVar/takeMVar(s) waiting: wake up the first one tso = StgMVarTSOQueue_tso(q); - StgMVar_head(mvar) = StgMVarTSOQueue_link(q); - if (StgMVar_head(mvar) == stg_END_TSO_QUEUE_closure) { + q = StgMVarTSOQueue_link(q); + StgMVar_head(mvar) = q; + if (q == stg_END_TSO_QUEUE_closure) { StgMVar_tail(mvar) = stg_END_TSO_QUEUE_closure; + } else { + if (info == stg_MVAR_CLEAN_info) { + // Resolve #18919. + ccall dirty_MVAR(BaseReg "ptr", mvar "ptr", + StgMVar_value(mvar) "ptr"); + } } ASSERT(StgTSO_block_info(tso) == mvar); @@ -1854,10 +1861,8 @@ loop: // If it was a readMVar, then we can still do work, // so loop back. (XXX: This could take a while) - if (why_blocked == BlockedOnMVarRead) { - q = StgMVarTSOQueue_link(q); + if (why_blocked == BlockedOnMVarRead) goto loop; - } ASSERT(why_blocked == BlockedOnMVar); @@ -1912,9 +1917,16 @@ loop: // There are takeMVar(s) waiting: wake up the first one tso = StgMVarTSOQueue_tso(q); - StgMVar_head(mvar) = StgMVarTSOQueue_link(q); - if (StgMVar_head(mvar) == stg_END_TSO_QUEUE_closure) { + q = StgMVarTSOQueue_link(q); + StgMVar_head(mvar) = q; + if (q == stg_END_TSO_QUEUE_closure) { StgMVar_tail(mvar) = stg_END_TSO_QUEUE_closure; + } else { + if (info == stg_MVAR_CLEAN_info) { + // Resolve #18919. + ccall dirty_MVAR(BaseReg "ptr", mvar "ptr", + StgMVar_value(mvar) "ptr"); + } } ASSERT(StgTSO_block_info(tso) == mvar); @@ -1939,10 +1951,8 @@ loop: // If it was a readMVar, then we can still do work, // so loop back. (XXX: This could take a while) - if (why_blocked == BlockedOnMVarRead) { - q = StgMVarTSOQueue_link(q); + if (why_blocked == BlockedOnMVarRead) goto loop; - } ASSERT(why_blocked == BlockedOnMVar); diff --git a/rts/Threads.c b/rts/Threads.c index 6050549d64..39616655ab 100644 --- a/rts/Threads.c +++ b/rts/Threads.c @@ -803,9 +803,14 @@ loop: // There are takeMVar(s) waiting: wake up the first one tso = q->tso; - mvar->head = q->link; - if (mvar->head == (StgMVarTSOQueue*)&stg_END_TSO_QUEUE_closure) { + mvar->head = q = q->link; + if (q == (StgMVarTSOQueue*)&stg_END_TSO_QUEUE_closure) { mvar->tail = (StgMVarTSOQueue*)&stg_END_TSO_QUEUE_closure; + } else { + if (info == &stg_MVAR_CLEAN_info) { + // Resolve #18919. + dirty_MVAR(&cap->r, (StgClosure*)mvar, mvar->value); + } } ASSERT(tso->block_info.closure == (StgClosure*)mvar); @@ -829,10 +834,8 @@ loop: // If it was a readMVar, then we can still do work, // so loop back. (XXX: This could take a while) - if (why_blocked == BlockedOnMVarRead) { - q = ((StgMVarTSOQueue*)q)->link; + if (why_blocked == BlockedOnMVarRead) goto loop; - } ASSERT(why_blocked == BlockedOnMVar); |