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Bug ID: JDK-6624782 Bigapps crashes during CMS precleaning.
JDK-6624782 : Bigapps crashes during CMS precleaning.

Details
Type:
Bug
Submit Date:
2007-11-01
Status:
Resolved
Updated Date:
2010-04-02
Project Name:
JDK
Resolved Date:
2008-04-23
Component:
hotspot
OS:
generic
Sub-Component:
gc
CPU:
generic
Priority:
P3
Resolution:
Fixed
Affected Versions:
7
Fixed Versions:
hs12 (b02)

Related Reports
Backport:
Backport:

Sub Tasks

Description
Crashes when running Toncat and Volano during bigapps testing.  Crashes occur
during cms precleaning.

The failures are both on 64bit VM's running on amd64 platforms.  The PC at the
time of the SEGV was pointing at the instruction

    __1cNobjArrayKlassUoop_oop_iterate_nv_m6MnDoop_pnbAMarkRefsIntoAndScanClosure_n0f 18 0c 36        prefetcht0 (%rsi,%rsi)

                                    

Comments
EVALUATION

The crashes point to a prefetchT0 instruction.  That instruction should
not throw any exceptions so it is unclear what is happening.  I've ask
that the tests be restarted with 

-XX:PrefetchFieldsAhead=0

which will eliminate the sue of the prefetch so should eliminate that
confusion.

I've also asked that a second bigapps run be done with

-XX:DisableIntrinsic="_arraycopy" -XX:PrefetchFieldsAhead=0

to workaround a possible (but at this point unlikely) c2 bug.  Both
runs has been going for more than a week without reproducing the 
failure.
                                     
2007-11-01
EVALUATION

The tests run with -XX:PrefetchFieldsAhead=0 ran without failure for
2-3 weeks.  New runs with the original flags only (no -XX:PrefetchFieldsAhead=0
and no -XX:DisableIntrinsic="_arraycopy") failed within 30 hours.
                                     
2007-11-19
EVALUATION

This failure is being investigate under 6635416 as a possible
SunStudio compiler bug.
                                     
2007-11-29
SUGGESTED FIX

--- old/build/solaris/makefiles/amd64.make	Tue Dec  4 14:20:20 2007
+++ new/build/solaris/makefiles/amd64.make	Tue Dec  4 14:20:20 2007
@@ -45,6 +45,10 @@
 OPT_CFLAGS/generateOptoStub.o = -xO2
 OPT_CFLAGS/thread.o = -xO2
 
+# Work around for 6624782
+OPT_CFLAGS/instanceKlass.o = -Qoption ube -no_a2lf
+OPT_CFLAGS/objArrayKlass.o = -Qoption ube -no_a2lf
+
 else
 
 ifeq ("${Platform_compiler}", "gcc")
                                     
2007-12-04



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