gcc 4.3.1-lubuntu2 debug code crashes in 8.10 with sigsegv in strlen

[Andrew Robb]

Binary package hint: gcc

I have a small source file which produces a sigsegv in debug code but runs fine optimised to -O3. However, assembler from SuSE compiler or gcc 4.3.3 built on ubuntu 8.10 from gcc.gnu.org source does not crash.

$ apt-cache policy gcc
gcc:
  Installed: 4:4.3.1-1ubuntu2
  Candidate: 4:4.3.1-1ubuntu2
  Version table:
 *** 4:4.3.1-1ubuntu2 0
        500 http://gb.archive.ubuntu.com intrepid/main Packages
        100 /var/lib/dpkg/status

$ gcc -g soundex.c -o soundex
$ ./soundex burroughs ashcroft brc mcknight mcnaught mcknawght
strlen("burroughs")
B620 burroughs
strlen("ashcroft")
Segmentation fault

Package gcc-3.4 also causes crash:
$ gcc-3.4 -g soundex.c -o soundex
$ ./soundex burroughs ashcroft brc mcknight mcnaught mcknawght
strlen("burroughs")
B620 burroughs
strlen("ashcroft")
Segmentation fault

$ apt-cache policy gcc-3.4
gcc-3.4:
  Installed: 3.4.6-8ubuntu2
  Candidate: 3.4.6-8ubuntu2
  Version table:
 *** 3.4.6-8ubuntu2 0
        500 http://gb.archive.ubuntu.com intrepid/universe Packages
        100 /var/lib/dpkg/status

strlen() does not crash if optimised in line (or if I use a home-brew compiler or SuSE compiler):
$ gcc -O3 soundex.c -o soundex
$ ./soundex burroughs ashcroft brc mcknight mcnaught mcknawght
strlen("burroughs")
B620 burroughs
strlen("ashcroft")
A261 ashcroft
strlen("brc")
B620 brc
strlen("mcknight")
M252 mcknight
strlen("mcnaught")
M252 mcnaught
strlen("mcknawght")
M252 mcknawght

[Andrew Robb (ajrobb)]

Many apologies, bug in line 66 of source - should be:

  while (src < end && dst < lim) {

I was polluting the stack - so hardly surprising that it crashed.