Below is part of the enc_String_Compare implementation
from file src/cpu/sparc/vm/sparc.ad .
The branch instruction marked with "set annul" comment
needs to have the annul bit set.  The code is shown
after applying the fix, which is to have the
second argument to br() be true.

 Without the annul bit, the delay slot fetch marked
"SEGV here" can execute a fetch one character past
the end of the "chr1" character array .  If the
chr1 character array is at the end of a memory space
and the next virtual address page is not committed,
a SEGV can result.

    // Compare the rest of the characters
    __ lduh(tmp1_reg, limit_reg, chr1_reg);
    __ bind(Lloop);
    // __ lduh(tmp1_reg, limit_reg, chr1_reg); // hoisted
    __ lduh(tmp2_reg, limit_reg, chr2_reg);
    __ subcc(chr1_reg, chr2_reg, chr1_reg);
    __ br(Assembler::notZero, false, Assembler::pt, Ldone);
    assert(chr1_reg == result_reg, "result must be pre-placed");
    __ delayed()->inccc(limit_reg, sizeof(jchar));
    __ br(Assembler::notZero, true, Assembler::pt, Lloop);  // set annul, gemstone fix 27662
    __ delayed()->lduh(tmp1_reg, limit_reg, chr1_reg); // hoisted  // SEGV here

This problem exists in src/cpu/sparc/vm/sparc.ad
for all of these J2SE versions :
  1.3.1.03
  1.4.0.01
  1.4.1 beta b14

I have not checked 1.2.x sources.
(Review ID: 153413) 
======================================================================

Disable compilation of any methods that would inline compareTo from
java.lang.String
======================================================================

  xxxxx@xxxxx   2002-06-13

    delayed()->lduh() after a backward branch can access memory after the 
end of the data structure when the loop has finished, possibly causing a SEGV.
Discovered in enc_String_Compare.

  xxxxx@xxxxx   2002-06-14

Fix putback to c2_baseline (mantis)

-----
  xxxxx@xxxxx   2002-07-12

Fix is approved for putback to hopper-rc.

We've had a production server crash due to this bug. Are you seriously not fixing it until next February? 
Would "exclude String compareTo" in .hotspot_compiler have the required effect?