svnserve segfaults on new FSFS format with limited memory

The SSH server on my machine runs with limited memory resources,
set via 'softlimit' <http://cr.yp.to/daemontools/softlimit.html>.
This used to work for years. However, the FSFS format introduced
in the 1.6.x series doesn't seem to like it:

   $ svnadmin create --fs-type fsfs repos

   $ svn co svn+ssh://USER@localhost/PATH/TO/repos
   svn: Network connection closed unexpectedly

The kernel log shows:

   kern.info: svnserve[27837]: segfault at 4b ip b7b5040d
   sp bfef2200 error 4 in libpthread-2.9.so[b7b4a000+14000]

It works okay if I use '--fs-type bdb' or '--pre-1.6-compatible'
to create the repos.

Local access via 'file://...' works in any case.

It also works when I set the memory limit very high:

   softlimit -m 900000000000 ...

It does _not_ work with 'softlimit -m 800000000000 ...'.

It is hard to believe that a memory limit of several hundreds of
gigabyte would not be enough. And, if the memory limit in fact
was an issue, there should be an 'out of memory' error message
and not a segfault. So, there seems to be something wrong here.

$ svn --version
svn, version 1.6.0 (r36650)
   compiled Apr 8 2009, 16:57:13

$ gcc --version
gcc (GCC) 4.1.2

GCC is compiled with hardening patches, e.g., for stack
protection.

Operating system is Linux 2.6.27.21.

Subversion is compiled with 'CFLAGS=CXXFLAGS=-march=i586
-mtune=i586'. It is configured with ' --disable-nls'. The test
suite ('make check') runs through fine.