valgrinding GCJ Java code
Boehm, Hans
hans.boehm@hp.com
Thu Jun 17 19:17:00 GMT 2004
I don't know what the specific issue is here.
I would expect lots of bogus problem reports for the garbage collector.
For example, the collector scans complete stacks for pointers. Some of those
stacks are likely to be uninitialized. (The way to fix these would be to
teach valgrind about the garbage collector. I don't know if it has hooks
for the GC to tell it what's going on.)
If you are looking for a memory overwrite problem, the patch in
http://gcc.gnu.org/ml/java/2004-03/msg00222.html (for which I'm still hoping
for feedback!) should also provide some checking, which might help.
Hans
> -----Original Message-----
> From: java-owner@gcc.gnu.org
> [mailto:java-owner@gcc.gnu.org]On Behalf Of
> Tom Schutter
> Sent: Thursday, June 17, 2004 9:20 AM
> To: java@gcc.gnu.org
> Subject: valgrinding GCJ Java code
>
>
> I have a mixed Java/C app that I am trying to run valgrind
> (http://valgrind.kde.org) on. The object of this exercise is
> to find a
> difficult-to-reproduce crash that is related to JNI and garbage
> collection. Most of the C code is valgrind clean, it is when
> it is used
> from JNI that I am having problems.
>
> It is obvious to me that valgrind will not be able to run a standard
> JVM, so I started looking into GCJ. GCJ will generate
> standard object
> code that I should be able to run valgrind on. But I am stuck at the
> starting gate.
>
> Valgrind hangs when I try to initialize the GCJ Java runtime.
> It hangs
> with both of the alternatives that GCJ provides, namely
> JvCreateJavaVM()
> and JNI_CreateJavaVM(), although I suspect that one is just a wrapper
> around the other.
>
> Debian testing/unstable
> Linux rota 2.6.3-1-686 #2 Tue Feb 24 20:24:38 EST 2004 i686 GNU/Linux
> ii valgrind 2.1.1-3 A memory debugger for x86-linux
> ii gcj-3.4 3.4.0-1 The GNU compiler for Java(TM)
> ii gcc-3.4 3.4.0-1 The GNU C compiler
>
> I have two easy test cases that follow. Both generated
> executables that
> run, but when run under valgrind, they hang (using 100% cpu) when
> initializing the Java runtime.
>
> /* vg_cni.cc
> * compile with:
> * gcc-3.4 vg_cni.cc -o vg_cni -lgcj
> */
>
> #include <gcj/cni.h>
> #include <stdio.h>
> #include <stdlib.h>
>
> int main(int argc, char *argv[]) {
> jint cni_error;
>
> /* Initialize the Java runtime. */
> printf("%s:%i\n", __FILE__, __LINE__);
> cni_error = JvCreateJavaVM(NULL);
> if (cni_error < 0) {
> printf(
> "ERROR: Unable to initialize the Java runtime, (%i)\n",
> (int) cni_error
> );
> return(EXIT_FAILURE);
> }
>
> printf("%s:%i\n", __FILE__, __LINE__);
> JvAttachCurrentThread(NULL, NULL);
>
> printf("%s:%i\n", __FILE__, __LINE__);
> JvDetachCurrentThread();
>
> printf("%s:%i\n", __FILE__, __LINE__);
> argc = argc;
> argv = argv;
> return(EXIT_SUCCESS);
> }
>
>
> /* vg_jni.c
> * compile with:
> * gcc-3.4 vg_jni.c -o vg_jni -lgcj
> */
>
> #include <jni.h>
> #include <stdio.h>
> #include <stdlib.h>
> #include <string.h>
>
> int main(int argc, char *argv[]) {
> JavaVMInitArgs vm_args;
> JNIEnv *env = NULL;
> JavaVM *jvm = NULL;
> jint jni_error;
>
> /* Setup the vm_args structure. */
> memset(&vm_args, 0, sizeof(vm_args));
> vm_args.version = JNI_VERSION_1_2;
>
> /* Create the Java Virtual Machine. */
> printf("%s:%i\n", __FILE__, __LINE__);
> jni_error = JNI_CreateJavaVM(&jvm, (void **) &env, &vm_args);
> if (jni_error < 0) {
> printf(
> "ERROR: Unable to create Java Virtual Machine, (%i)\n",
> (int) jni_error
> );
> return(EXIT_FAILURE);
> }
>
> printf("%s:%i\n", __FILE__, __LINE__);
> if ((*env)->ExceptionOccurred(env)) {
> printf("exception occurred %s:%i\n", __FILE__, __LINE__);
> }
>
> printf("%s:%i\n", __FILE__, __LINE__);
> (*jvm)->DestroyJavaVM(jvm);
>
> printf("%s:%i\n", __FILE__, __LINE__);
> argc = argc;
> argv = argv;
> return(EXIT_SUCCESS);
> }
>
>
> $ valgrind vg_cni
> ==5831== Memcheck, a memory error detector for x86-linux.
> ==5831== Copyright (C) 2002-2004, and GNU GPL'd, by Julian Seward.
> ==5831== Using valgrind-2.1.1, a program supervision framework for
> x86-linux.
> ==5831== Copyright (C) 2000-2004, and GNU GPL'd, by Julian Seward.
> ==5831== For more details, rerun with: -v
> ==5831==
> vg_cni.cc:14
> ==5831== Syscall param sigaction(act) contains uninitialised or
> unaddressable byte(s)
> ==5831== at 0x3CA36025: __libc_sigaction (in
> /lib/tls/libc-2.3.2.so)
> ==5831== Address 0x4FFFE830 is on thread 1's stack
> ==5831==
> ==5831== Syscall param sigaction(act) contains uninitialised or
> unaddressable byte(s)
> ==5831== at 0x3CA36025: __libc_sigaction (in
> /lib/tls/libc-2.3.2.so)
> ==5831== by 0x7FFFFFFB: ???
> ==5831== Address 0x4FFFE780 is on thread 1's stack
> ==5831==
> ==5831== Conditional jump or move depends on uninitialised value(s)
> ==5831== at 0x3C646535: GC_push_all_eager (in
> /usr/lib/libgcj.so.5.0.0)
> ==5831== by 0x3C6478C9: GC_push_current_stack (in
> /usr/lib/libgcj.so.5.0.0)
> ==5831== by 0x3C64E12D: GC_generic_push_regs (in
> /usr/lib/libgcj.so.5.0.0)
> ==5831== by 0x3C6479FD: GC_push_roots (in /usr/lib/libgcj.so.5.0.0)
> ==5831==
> ==5831== Conditional jump or move depends on uninitialised value(s)
> ==5831== at 0x3C64653A: GC_push_all_eager (in
> /usr/lib/libgcj.so.5.0.0)
> ==5831== by 0x3C6478C9: GC_push_current_stack (in
> /usr/lib/libgcj.so.5.0.0)
> ==5831== by 0x3C64E12D: GC_generic_push_regs (in
> /usr/lib/libgcj.so.5.0.0)
> ==5831== by 0x3C6479FD: GC_push_roots (in /usr/lib/libgcj.so.5.0.0)
> ==5831==
> ==5831== Conditional jump or move depends on uninitialised value(s)
> ==5831== at 0x3C646535: GC_push_all_eager (in
> /usr/lib/libgcj.so.5.0.0)
> ==5831== by 0x3C6465B9: GC_push_all_stack (in
> /usr/lib/libgcj.so.5.0.0)
> ==5831== by 0x3C64DB96: GC_push_all_stacks (in
> /usr/lib/libgcj.so.5.0.0)
> ==5831== by 0x3C649815: GC_default_push_other_roots (in
> /usr/lib/libgcj.so.5.0.0)
> ==5831==
> ==5831== Syscall param sigaction(act) contains uninitialised or
> unaddressable byte(s)
> ==5831== at 0x3CAE551D: syscall (in /lib/tls/libc-2.3.2.so)
> ==5831== by 0x8048736: JvCreateJavaVM(void*) (in
> /home/tom/tmp/valgrind_gcj/vg_cni)
> ==5831== by 0x8048670: main (in /home/tom/tmp/valgrind_gcj/vg_cni)
> ==5831== Address 0x4FFFE9B0 is on thread 1's stack
> ==5831==
> ==5831== Conditional jump or move depends on uninitialised value(s)
> ==5831== at 0x3C64D25C: GC_pthread_create (in
> /usr/lib/libgcj.so.5.0.0)
> ==5831== by 0x3C472162: _Jv_ThreadStart(java::lang::Thread*,
> _Jv_Thread_t*, void (*)(java::lang::Thread*)) (in
> /usr/lib/libgcj.so.5.0.0)
> ==5831== by 0x3C49E6A6: java::lang::Thread::start() (in
> /usr/lib/libgcj.so.5.0.0)
> ==5831== by 0x3C473E09: _Jv_CreateJavaVM(void*) (in
> /usr/lib/libgcj.so.5.0.0)==5831==
> ==5831== Thread 2:
> ==5831== Conditional jump or move depends on uninitialised value(s)
> ==5831== at 0x3CB4CFF1: thread_wrapper (vg_libpthread.c:824)
> ==5831== by 0xB800FACC: do__quit (vg_scheduler.c:1792)
> ==5831==
> ==5831== Thread 2:
> ==5831== thread_wrapper: invalid attr->__detachstate
> ==5831== at 0x3CB4C00F: pthread_error (vg_libpthread.c:355)
> ==5831== by 0x3CB4D000: thread_wrapper (vg_libpthread.c:826)
> ==5831== by 0xB800FACC: do__quit (vg_scheduler.c:1792)
> ==5831==
> ==5831== Thread 2:
> ==5831== Conditional jump or move depends on uninitialised value(s)
> ==5831== at 0x3CB4D004: thread_wrapper (vg_libpthread.c:827)
> ==5831== by 0xB800FACC: do__quit (vg_scheduler.c:1792)
> ------------------------hangs here-----------------------------
>
> --
> Tom Schutter (mailto:tom@platte.com)
> Platte River Associates, Inc. (http://www.platte.com)
>
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