kernel BUG at jfs_dmap.c:776 (2.4.21)

Hi,

while doing some benchmarks, i noticed a segfault when trying to mount a newly created JFS. mkfs.jfs passes, but mount gives:

BUG at jfs_dmap.c:776 assert(hint < mapSize)
kernel BUG at jfs_dmap.c:776!
mount(1055): Kernel Bug 1
pc = [<fffffffc003236b4>] ra = [<fffffffc003236a8>] ps = 0000 Not tainted

v0 = 000000000000001e  t0 = 0000000000000001  t1 = 0000000000000000
t2 = fffffc00011d2948  t3 = 0000000000000000  t4 = ffffffff00000000
t5 = 0000000000000001  t6 = 343c0a29657a6953  t7 = fffffc0002cf8000
a0 = 0000000000000000  a1 = 0000000000000001  a2 = 0000000000000001
a3 = 0000000000000001  a4 = 0000000000000001  a5 = 0000000000000002
t8 = 0000000000000004  t9 = 0000000000001c0e  t10= 0000000000001c0f
t11= fffffc00011f0988  pv = fffffc000101fb90  at = fffffc00011f0988
gp = fffffffc00347c88  sp = fffffc0002cfb9e8
Trace:fffffc0001029f50 fffffc0001053b88 fffffc0001054838 fffffc000103e1ac fffffc00010168b0 fffffc000105808c fffffc00010585a4 fffffc0001058434 fffffc0001070b28 fffffc0001070f3c fffffc0001070d18 fffffc000107155c fffffc0001071538 fffffc0001010d30 fffffc0001010c88
Code: 22106a0c  47e90411  6b5b4106  27ba0002  23bd45e0  00000081 <c3fffecb> 47ff041f

this is with vanilla 2.4.21 (Alpha), compiled with gcc3.3, glibc 2.3.1, util-linux 2.11z.

thanks,
Christian.