breakpoints/2538: SIGILL after resuming from a breakpoint within a JVM process

[lineonking at gmail dot com]

>Number:         2538
>Category:       breakpoints
>Synopsis:       SIGILL after resuming from a breakpoint within a JVM process
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    unassigned
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Mon Oct 20 01:58:02 UTC 2008
>Closed-Date:
>Last-Modified:
>Originator:     lineonking@gmail.com
>Release:        GDB-6.8
>Organization:
>Environment:
powerpc-linux2.6.20-17 + IBM java 1.6
>Description:
Resuming after a breakpoint within a IBM JVM triggers a SIGILL exception. This SIGILL does not happen without the gdb. I guess that some strange thing is going on.
>How-To-Repeat:
0. download PingPong.java and PingPong.c.

1. compile
(bash) gcc -I $JAVA_HOME/include -o libPingPong.so -shared -g PingPong.c
(bash) javac -g PingPong.java

2. check if running well.
(bash) java -version
java version "1.6.0"
Java(TM) SE Runtime Environment (build pxp3260sr1-20080416_01(SR1))
...
(bash)java PingPong
jPing: 3
cPong: 2
jPing: 1
cPong: 0

3. check if gdb correctly resums after a breakpoint.
(bash) gdb --args java PingPong
GNU gdb 6.8
...
(bash) shell tail PingPong.c
JNIEXPORT jint JNICALL Java_PingPong_cPong(
  JNIEnv *env, jclass cls, jint i
) {
  printf("cPong: %d\n", i);
  if ( i > 0) {
    jmethodID mid = (*env)->GetStaticMethodID(env, cls, "jPing", "(I)I");
      (*env)->CallStaticIntMethod(env, cls, mid, i-1);
  }
  return i;
}
(gdb) b Java_PingPong_cPong
...
Make breakpoint pending on future shared library load? (y or [n]) y

Breakpoint 1 (Java_PingPong_cPong) pending.
(gdb) r
...

Breakpoint 1, Java_PingPong_cPong (env=0x100bfe00, cls=0x1042bc60, i=2)
    at PingPong.c:19
19	  printf("cPong: %d\n", i);
(gdb) disas
Dump of assembler code for function Java_PingPong_cPong:
0x0ed9b94c <Java_PingPong_cPong+0>:	stwu    r1,-64(r1)
0x0ed9b950 <Java_PingPong_cPong+4>:	mflr    r0
0x0ed9b954 <Java_PingPong_cPong+8>:	stw     r31,60(r1)
0x0ed9b958 <Java_PingPong_cPong+12>:	stw     r0,68(r1)
0x0ed9b95c <Java_PingPong_cPong+16>:	mr      r31,r1
0x0ed9b960 <Java_PingPong_cPong+20>:	stw     r3,28(r31)
0x0ed9b964 <Java_PingPong_cPong+24>:	stw     r4,24(r31)
0x0ed9b968 <Java_PingPong_cPong+28>:	stw     r5,20(r31)
0x0ed9b96c <Java_PingPong_cPong+32>:	.long 0x7d820eda
...
(gdb) continue
Continuing.

Program received signal SIGILL, Illegal instruction.
Java_PingPong_cPong (env=0x100bfe00, cls=0x1042bc60, i=2) at PingPong.c:19
19	  printf("cPong: %d\n", i);
(gdb) cont
Continuing.
Unhandled exception
Type=Illegal instruction vmState=0x00000000
J9Generic_Signal_Number=00000010 Signal_Number=00000004 Error_Value=00000000 Signal_Code=00000001
Handler1=0FAF97E0 Handler2=0FA31700
...
(bash)

>Fix:

>Release-Note:
>Audit-Trail:
>Unformatted: