Bug 14146 - sgen-only test failures in mono/tests/gc-altstack.exe
Summary: sgen-only test failures in mono/tests/gc-altstack.exe
Alias: None
Product: Runtime
Classification: Mono
Component: GC ()
Version: unspecified
Hardware: PC Linux
: --- normal
Target Milestone: ---
Assignee: Bugzilla
Depends on:
Reported: 2013-08-21 11:09 UTC by Charles Randall
Modified: 2013-10-02 16:52 UTC (History)
4 users (show)

Is this bug a regression?: ---
Last known good build:

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Description Charles Randall 2013-08-21 11:09:20 UTC
Running on OpenSuse 12.3/x86_64 with git master from today at d71ca46641a6cb7feffb471f86673451f434dda2.

I have disabled all AOT at configure time to work around other problems. Exact build steps are,

  make clean
  git pull
  ./autogen.sh --prefix=/tmp/mono-master
  ./configure --prefix=/tmp/mono-master --enable-minimal=aot --disable-system-aot
  make -j 4
  make install

The resulting mono is,

# mono --version
Mono JIT compiler version 3.3.0 (master/d71ca46 Wed Aug 21 08:41:07 MDT 2013)
Copyright (C) 2002-2012 Novell, Inc, Xamarin Inc and Contributors. www.mono-project.com
        TLS:           __thread
        SIGSEGV:       altstack
        Notifications: epoll
        Architecture:  amd64
        Disabled:      aot
        Misc:          softdebug
        LLVM:          supported, not enabled.
        GC:            sgen

The test mono/tests/gc-altstack.exe fails ~1% of the time with no meaningful output. To reproduce the problem,

# i=0; while mono ./gc-altstack.exe; do i=`expr $i + 1`; echo $i -----; done
1 -----
27 -----

Native stacktrace:

Segmentation fault

This is not reducible with --gc=boehm in a few thousand iterations.

Side note... Don't know if it's interesting or not but this test runs significantly faster using the boehm gc instead of sgen.
Comment 1 Charles Randall 2013-08-21 11:17:40 UTC
As a double-check that AOT is really disabled, this test still fails with "-O=-aot".

# i=0; while mono -O=-aot ./gc-altstack.exe; do i=`expr $i + 1`; echo $i -----; done
360 -----

Native stacktrace:

Segmentation fault
Comment 2 Mark Probst 2013-10-02 16:52:43 UTC
Fixed in 8828fafe297e758858468c2e96054ae101ea7227.