Bug 10351 – [GC] GC deadlocks in thread_suspendAll()

Here is an excerpt from a stack trace I got while profiling with OProfile: #0 sem_wait () from /lib64/libpthread.so.0 #1 thread_suspendAll () at core/thread.d:2471 #2 gc.gcx.Gcx.fullcollect() (this=...) at gc/gcx.d:2427 #3 gc.gcx.Gcx.bigAlloc() (this=..., size=16401, poolPtr=0x7fc3d4bfe3c8, alloc_size=0x7fc3d4bfe418) at gc/gcx.d:2099 #4 gc.gcx.GC.mallocNoSync (alloc_size=0x7fc3d4bfe418, bits=10, size=16401, this=...) gc/gcx.d:503 #5 gc.gcx.GC.malloc() (this=..., size=16401, bits=10, alloc_size=0x7fc3d4bfe418) gc/gcx.d:421 #6 gc.gc.gc_qalloc (ba=10, sz=<optimized out>) gc/gc.d:203 #7 gc_qalloc (sz=<optimized out>, ba=10) gc/gc.d:198 #8 _d_newarrayT (ti=..., length=4096) rt/lifetime.d:807 #9 sequencer.algorithm.gzip.HuffmanTree.__T6__ctorTG32hZ.__ctor() (this=..., bitLengths=...) sequencer/algorithm/gzip.d:444 Two more threads are alive, but waiting on a condition variable (i.e.: in pthread_cond_wait(), but from my own and not from druntime code. Is there some obvious way I could have dead-locked the GC ? Or is there a bug ? This was compiled with GDC using DMD FE 2.062. I wasn't able to reproduce this without the profiler running.

I wish I uploaded a test case, but the one I had was rather large and you can't really dustmite a deadlock condition even if it happens frequently.

Closing this for now without a test case.

*** This issue has been marked as a duplicate of issue 4890 ***

issue 4890 is reproduced on a newly created thread, is it the case for you? If it's a kernel bug, say what OS, kernel version and processor (speed, cores, HT) do you use.

also provide stack traces of other threads

Having this issue only under profile build (dub --build=profile) (gdb) bt #0 sem_wait () at ../nptl/sysdeps/unix/sysv/linux/x86_64/sem_wait.S:85 #1 0x00000000011bbc4e in thread_suspendAll () #2 0x00000000011a22e1 in gc.impl.conservative.gc.Gcx.fullcollect() () #3 0x00000000011a078e in gc.impl.conservative.gc.Gcx.bigAlloc() () #4 0x00000000011a4659 in gc.impl.conservative.gc.ConservativeGC.__T9runLockedS79_D2gc4impl12conservative2gc14ConservativeGC12mallocNoSyncMFNbmkKmxC8TypeInfoZPvS40_D2gc4impl12conservative2gc10mallocTimelS40_D2gc4impl12conservative2gc10numMallocslTmTkTmTxC8TypeInfoZ.runLocked() () #5 0x000000000119dd4a in gc.impl.conservative.gc.ConservativeGC.malloc() () #6 0x000000000113ba6b in gc_malloc () #7 0x000000000113e8db in _d_newclass () #8 0x0000000000ff21f8 in vibe.core.drivers.libevent2.Libevent2Driver.connectTCP() (this=0x6de2dda2b500, bind_addr=..., addr=...) at ../.dub/packages/vibe-d-0.8.0-beta.8/vibe-d/core/vibe/core/drivers/libevent2.d:347 #9 0x000000000104a60a in vibe.core.net.connectTCP() (bind_address=..., addr=...) at ../.dub/packages/vibe-d-0.8.0-beta.8/vibe-d/core/vibe/core/driver.d:33 #10 0x0000000000a560fc in handle.GetRTXmlResponse() (Xml=1187, __Xml_8=0x1247e2a <_TMP9856>) at ../.dub/packages/vibe-d-0.8.0-beta.8/vibe-d/core/vibe/core/net.d:145 #11 0x0000000000a538af in app._sharedStaticCtor13() () at source/app.d:215 #12 0x0000000000a55db5 in app.__modsharedctor() () #13 0x00000000011a8f42 in rt.minfo.__T14runModuleFuncsS442rt5minfo11ModuleGroup8runCtorsMFZ9__lambda2Z.runModuleFuncs() () #14 0x00000000011a8bd5 in rt.minfo.ModuleGroup.runCtors() () #15 0x00000000011a8ded in rt.minfo.rt_moduleCtor() () #16 0x0000000001143341 in rt.sections_elf_shared.DSO.opApply() () #17 0x00000000011a8dbd in rt_moduleCtor () #18 0x00000000011a637b in rt_init () #19 0x000000000113da52 in rt.dmain2._d_run_main() () #20 0x000000000113d9f8 in rt.dmain2._d_run_main() () #21 0x000000000113d968 in _d_run_main () #22 0x0000000000a6ce70 in main () (gdb) info threads Id Target Id Frame * 1 Thread 0x6de2ddb2dc00 (LWP 4036) "rtsrtorrentrela" sem_wait () at ../nptl/sysdeps/unix/sysv/linux/x86_64/sem_wait.S:85 Occurs early when running the program

*** This issue has been marked as a duplicate of issue 15939 ***