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digitalmars.D.bugs - [Issue 20270] New: [REG2.087] Deadlock in garbage collection when

https://issues.dlang.org/show_bug.cgi?id=20270

          Issue ID: 20270
           Summary: [REG2.087] Deadlock in garbage collection when running
                    processes in parallel
           Product: D
           Version: D2
          Hardware: x86_64
                OS: Linux
            Status: NEW
          Severity: regression
          Priority: P1
         Component: druntime
          Assignee: nobody puremagic.com
          Reporter: dlang-bugzilla thecybershadow.net
                CC: r.sagitario gmx.de

///////////// test.d /////////////
import std.parallelism;
import std.process;
import std.range;

void main()
{
    foreach (i; 200.iota.parallel)
        execute(["true"]);
}
//////////////////////////////////

This program has a roughly 60% chance to deadlock and never finish executing on
my machine.

Inspecting the program's state with a debugger shows that the threads are
generally in one of these states:

Thread 11 (Thread 0x7f2a80ff9700 (LWP 424924)):



nothrow delegate) ()



...


Thread 10 (Thread 0x7f2a817fa700 (LWP 424923)):



nothrow delegate) ()



...

Thread 9 (Thread 0x7f2a81ffb700 (LWP 424922)):



nothrow delegate) ()





...

Thread 8 (Thread 0x7f2a827fc700 (LWP 424921)):



nothrow delegate) ()




()

()


_D2gc4impl12conservativeQw14ConservativeGC__T9runLockedS_DQCeQCeQCcQCnQBs12mallocNoSyncMFNbmkKmxC8TypeInfoZPvS_DQEgQEgQEeQEp10mallocTimelS_DQFiQFiQFgQFr10numMallocslTmTkTmTxQCzZQFcMFNbKmKkKmKxQDsZQDl
()

_D2gc4impl12conservativeQw14ConservativeGC6qallocMFNbmkxC8TypeInfoZS4core6memory8BlkInfo_
()

...

Thread 7 (Thread 0x7f2a82ffd700 (LWP 424920)):



_D2gc4impl12conservativeQw3Gcx16startScanThreadsMFNbZv ()

()


_D2gc4impl12conservativeQw3Gcx8bigAllocMFNbmKmkxC8TypeInfoZPv ()

_D2gc4impl12conservativeQw14ConservativeGC__T9runLockedS_DQCeQCeQCcQCnQBs12mallocNoSyncMFNbmkKmxC8TypeInfoZPvS_DQEgQEgQEeQEp10mallocTimelS_DQFiQFiQFgQFr10numMallocslTmTkTmTxQCzZQFcMFNbKmKkKmKxQDsZQDl
()

_D2gc4impl12conservativeQw14ConservativeGC6qallocMFNbmkxC8TypeInfoZS4core6memory8BlkInfo_
()

...

--
Oct 06 2019