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| author | Simon Marlow <marlowsd@gmail.com> | 2017-06-03 20:26:13 +0100 |
|---|---|---|
| committer | Simon Marlow <marlowsd@gmail.com> | 2017-06-08 08:38:09 +0100 |
| commit | 598472908ebb08f6811b892f285490554c290ae3 (patch) | |
| tree | 84079aceefe1a7eacda507f104c0f0d4d8c12417 /testsuite/tests/concurrent | |
| parent | bca56bd040de64315564cdac4b7e943fc8a75ea0 (diff) | |
| download | haskell-598472908ebb08f6811b892f285490554c290ae3.tar.gz | |
Fix a lost-wakeup bug in BLACKHOLE handling (#13751)
Summary:
The problem occurred when
* Threads A & B evaluate the same thunk
* Thread A context-switches, so the thunk gets blackholed
* Thread C enters the blackhole, creates a BLOCKING_QUEUE attached to
the blackhole and thread A's `tso->bq` queue
* Thread B updates the blackhole with a value, overwriting the BLOCKING_QUEUE
* We GC, replacing A's update frame with stg_enter_checkbh
* Throw an exception in A, which ignores the stg_enter_checkbh frame
Now we have C blocked on A's tso->bq queue, but we forgot to check the
queue because the stg_enter_checkbh frame has been thrown away by the
exception.
The solution and alternative designs are discussed in Note [upd-black-hole].
This also exposed a bug in the interpreter, whereby we were sometimes
context-switching without calling `threadPaused()`. I've fixed this
and added some Notes.
Test Plan:
* `cd testsuite/tests/concurrent && make slow`
* validate
Reviewers: niteria, bgamari, austin, erikd
Reviewed By: erikd
Subscribers: rwbarton, thomie
GHC Trac Issues: #13751
Differential Revision: https://phabricator.haskell.org/D3630
Diffstat (limited to 'testsuite/tests/concurrent')
| -rw-r--r-- | testsuite/tests/concurrent/should_run/all.T | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/testsuite/tests/concurrent/should_run/all.T b/testsuite/tests/concurrent/should_run/all.T index 16363ed0b8..69b8ad7a1e 100644 --- a/testsuite/tests/concurrent/should_run/all.T +++ b/testsuite/tests/concurrent/should_run/all.T @@ -266,6 +266,7 @@ test('hs_try_putmvar001', # This one should work for both threaded and non-threaded RTS test('hs_try_putmvar002', [pre_cmd('$MAKE -s --no-print-directory hs_try_putmvar002_setup'), + omit_ways(['ghci']), extra_run_opts('1 8 10000')], compile_and_run, ['hs_try_putmvar002_c.c']) |