[Git][ghc/ghc][wip/tsan/fix-races] 28 commits: rts: Style fixes

Ben Gamari (@bgamari) gitlab at gitlab.haskell.org
Mon Jul 24 18:33:45 UTC 2023 


Ben Gamari pushed to branch wip/tsan/fix-races at Glasgow Haskell Compiler / GHC


Commits:
a38fa0bf by Ben Gamari at 2023-07-24T14:33:01-04:00
rts: Style fixes

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a7d012c9 by Ben Gamari at 2023-07-24T14:33:14-04:00
codeGen/tsan: Rework handling of spilling

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f7decdf3 by Ben Gamari at 2023-07-24T14:33:14-04:00
hadrian: More debug information

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d53eb92e by Ben Gamari at 2023-07-24T14:33:14-04:00
Improve TSAN documentation

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75437706 by Ben Gamari at 2023-07-24T14:33:15-04:00
hadrian: More selective TSAN instrumentation

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f02a8a0f by Ben Gamari at 2023-07-24T14:33:32-04:00
rts: Fix data race in threadPaused

This only affects an assertion in the debug RTS, but it's a data race
nevertheless.

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0b347896 by Ben Gamari at 2023-07-24T14:33:32-04:00
cmm: Introduce MO_RelaxedRead

In hand-written Cmm it can sometimes be necessary to atomically load
from memory deep within an expression (e.g. see the `CHECK_GC` macro).
This MachOp provides a convenient way to do so without breaking the
expression into multiple statements.

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7164a60c by Ben Gamari at 2023-07-24T14:33:32-04:00
rts: Silence spurious data races in ticky counters

Previously we would use non-atomic accesses when bumping ticky counters,
which would result in spurious data race reports from ThreadSanitizer
when the threaded RTS was in use.

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70cfaa0a by Ben Gamari at 2023-07-24T14:33:32-04:00
codeGen: Use relaxed accesses in ticky bumping

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85afd351 by Ben Gamari at 2023-07-24T14:33:32-04:00
rts: Fix data race in Interpreter's preemption check

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6c127548 by Ben Gamari at 2023-07-24T14:33:32-04:00
rts: Fix data race in threadStatus#

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24fc3475 by Ben Gamari at 2023-07-24T14:33:32-04:00
rts: Fix data race in CHECK_GC

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3791b8fc by Ben Gamari at 2023-07-24T14:33:32-04:00
base: use atomic write when updating timer manager

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f623c923 by Ben Gamari at 2023-07-24T14:33:32-04:00
Use relaxed atomics to manipulate TSO status fields

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30b9be29 by Ben Gamari at 2023-07-24T14:33:32-04:00
rts: Add necessary barriers when manipulating TSO owner

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d7f9ef7a by Ben Gamari at 2023-07-24T14:33:32-04:00
rts: Fix synchronization on thread blocking state

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270c7542 by Ben Gamari at 2023-07-24T14:33:32-04:00
rts: Relaxed load MutVar info table

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4a778fe8 by Ben Gamari at 2023-07-24T14:33:32-04:00
Wordsmith TSAN Note

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ac5d7458 by Ben Gamari at 2023-07-24T14:33:32-04:00
codeGen: Use relaxed-read in closureInfoPtr

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43534f63 by Ben Gamari at 2023-07-24T14:33:32-04:00
Fix thunk update ordering

Previously we attempted to ensure soundness of concurrent thunk update
by synchronizing on the access of the thunk's info table pointer field.
This was believed to be sufficient since the indirectee (which may
expose a closure allocated by another core) would not be examined
until the info table pointer update is complete.

However, it turns out that this can result in data races in the presence
of multiple threads racing a update a single thunk. For instance,
consider this interleaving under the old scheme:

            Thread A                             Thread B
            ---------                            ---------
    t=0     Enter t
      1     Push update frame
      2     Begin evaluation

      4     Pause thread
      5     t.indirectee=tso
      6     Release t.info=BLACKHOLE

      7     ... (e.g. GC)

      8     Resume thread
      9     Finish evaluation
      10    Relaxed t.indirectee=x

      11                                         Load t.info
      12                                         Acquire fence
      13                                         Inspect t.indirectee

      14    Release t.info=BLACKHOLE

Here Thread A enters thunk `t` but is soon paused, resulting in `t`
being lazily blackholed at t=6. Then, at t=10 Thread A finishes
evaluation and updates `t.indirectee` with a relaxed store.

Meanwhile, Thread B enters the blackhole. Under the old scheme this
would introduce an acquire-fence but this would only synchronize with
Thread A at t=6. Consequently, the result of the evaluation, `x`, is not
visible to Thread B, introducing a data race.

We fix this by treating the `indirectee` field as we do all other
mutable fields. This means we must always access this field with
acquire-loads and release-stores.

See #23185.

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dd34c0be by Ben Gamari at 2023-07-24T14:33:32-04:00
STM: Use acquire loads when possible

Full sequential consistency is not needed here.

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d8ef8b00 by Ben Gamari at 2023-07-24T14:33:32-04:00
rts/Interpreter: Fix data race

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58a6dd60 by Ben Gamari at 2023-07-24T14:33:32-04:00
rts/Messages: Fix data race

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5cb1825c by Ben Gamari at 2023-07-24T14:33:32-04:00
rts/Prof: Fix data race

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1f7cb9ab by Ben Gamari at 2023-07-24T14:33:32-04:00
rts: Fix various data races

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f8158fea by Ben Gamari at 2023-07-24T14:33:32-04:00
rts: Use fence rather than redundant load

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34422ee6 by Ben Gamari at 2023-07-24T14:33:32-04:00
rts/RaiseAsync: Drop redundant release fence

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b778e090 by Ben Gamari at 2023-07-24T14:33:32-04:00
rts: Fixes profiling timer races

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30 changed files:

- compiler/GHC/Cmm/Expr.hs
- compiler/GHC/Cmm/Info.hs
- compiler/GHC/Cmm/MachOp.hs
- compiler/GHC/Cmm/Parser.y
- compiler/GHC/Cmm/ThreadSanitizer.hs
- compiler/GHC/CmmToAsm/AArch64/CodeGen.hs
- compiler/GHC/CmmToAsm/PPC/CodeGen.hs
- compiler/GHC/CmmToAsm/Wasm/FromCmm.hs
- compiler/GHC/CmmToAsm/X86/CodeGen.hs
- compiler/GHC/CmmToC.hs
- compiler/GHC/CmmToLlvm/CodeGen.hs
- compiler/GHC/StgToCmm/Bind.hs
- compiler/GHC/StgToCmm/Ticky.hs
- compiler/GHC/StgToCmm/Utils.hs
- hadrian/src/Flavour.hs
- libraries/base/GHC/Event/Thread.hs
- rts/Apply.cmm
- rts/Compact.cmm
- rts/Exception.cmm
- rts/Heap.c
- rts/HeapStackCheck.cmm
- rts/Interpreter.c
- rts/Messages.c
- rts/PrimOps.cmm
- rts/Proftimer.c
- rts/RaiseAsync.c
- rts/STM.c
- rts/Schedule.c
- rts/StableName.c
- rts/StgMiscClosures.cmm


The diff was not included because it is too large.


View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/baafa60e240b05a2a225ec0b730447db8837a1a4...b778e09017b1ce08b93a426fa194b2252e730d8b

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View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/baafa60e240b05a2a225ec0b730447db8837a1a4...b778e09017b1ce08b93a426fa194b2252e730d8b
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