That's interesting.
Some cases where I get segfaults:

======= v5.6.1 built for i586-linux, on Linux central 2.4.18 #9 SMP

kurt@central:~> perl -e 'chop foo'
Segmentation fault
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======= v5.6.1 built for sun4-solaris, on SunOS xxxx 5.8 Generic_108528-14 sun4u sparc SUNW,Sun-Fire

[xxxxx: ~] perl -e 'chop foo'
Modification of a read-only value attempted.
Segmentation Fault (core dumped)
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======= v5.6.1 built for alpha-dec_osf, on OSF1 xxxx V4.0 1229 alpha

[xxxxx: ~] perl -e 'chop foo'
Segmentation fault (core dumped)
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======= v5.6.1 built for PA-RISC1.1, on HP-UX xxxx B.11.11 U 9000/800

yyyy@xxxx:¨> perl -e 'chop foo'
Modification of a read-only value attempted.
Bus error(coredump)
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----- kurt