coreutils test failure due to OOPS in amd64 linux-2.6.9: tmpfs-related

[Jim Meyering]

For the record, there seems to be a bug in amd64 linux-2.6.9 that
causes (soon-to-be-released) coreutils-5.3.1's tests/part-symlink
to fail with lots of segfaults (and kernel OOPSs) if the working
directory name is long enough.

I'm not planning to make the test work around it, since 2.6.9 is
pretty old for AMD64, and this isn't a problem with newer kernels.

The problem is that we get an OPPS when unlinking a symlink in
/dev/shm (tmpfs) when that symlink's value is 41 bytes or longer.

Here's a pared-down demo:

Unlinking a symlink with a 40-byte value works fine:
  $ ln -s $(printf %040d 0) /dev/shm/x; unlink /dev/shm/x

Unlinking a symlink with a 41-byte value causes the OOPS:
  $ ln -s $(printf %041d 0) /dev/shm/x; unlink /dev/shm/x
  Killed
  [Exit 137 (SIGKILL)]
  $
  Message from address@hidden at Sun Sep 25 05:12:42 2005 ...
  xxxx kernel: Oops: 0000 [124] SMP

  Message from address@hidden at Sun Sep 25 05:12:42 2005 ...
  xxxx kernel: CR2: 0000000000000090

$ df -hT /dev/shm
Filesystem    Type    Size  Used Avail Use% Mounted on
none         tmpfs    3.7G     0  3.7G   0% /dev/shm

$ uname -r
2.6.9-1.667smp