Bug#484507: grub-pc postinst fails silently

[Pierre Habouzit]

Package: grub-pc
Version: 1.96+20080601-2
Severity: serious

Excerpt from today's update:

    Setting up grub-pc (1.96+20080601-2) ...
    Installing new version of config file /etc/grub.d/10_linux ...
    *** glibc detected *** /usr/sbin/grub-probe: realloc(): invalid next size: 0x0000000001bf83d0 ***
    ======= Backtrace: =========
    /lib/libc.so.6[0x7fea45626978]
    /lib/libc.so.6[0x7fea4562a571]
    /lib/libc.so.6(realloc+0x12f)[0x7fea4562afef]
    /usr/sbin/grub-probe[0x402ff9]
    /usr/sbin/grub-probe[0x411cb9]
    /usr/sbin/grub-probe[0x411d80]
    /usr/sbin/grub-probe[0x4130ac]
    /usr/sbin/grub-probe[0x4182da]
    /usr/sbin/grub-probe[0x4016f2]
    /usr/sbin/grub-probe[0x401b68]
    /lib/libc.so.6(__libc_start_main+0xe6)[0x7fea455d11a6]
    /usr/sbin/grub-probe[0x4014a9]
    ======= Memory map: ========
    00400000-00422000 r-xp 00000000 08:03 22141                              /usr/sbin/grub-probe
    00622000-00623000 rwxp 00022000 08:03 22141                              /usr/sbin/grub-probe
    00623000-0062f000 rwxp 00623000 00:00 0 
    01be2000-02130000 rwxp 01be2000 00:00 0                                  [heap]
    7fea40000000-7fea40021000 rwxp 7fea40000000 00:00 0 
    7fea40021000-7fea44000000 ---p 7fea40021000 00:00 0 
    7fea4539c000-7fea453b2000 r-xp 00000000 08:03 4625183                    /lib/libgcc_s.so.1
    7fea453b2000-7fea455b2000 ---p 00016000 08:03 4625183                    /lib/libgcc_s.so.1
    7fea455b2000-7fea455b3000 rwxp 00016000 08:03 4625183                    /lib/libgcc_s.so.1
    7fea455b3000-7fea456fd000 r-xp 00000000 08:03 4822269                    /lib/libc-2.7.so
    7fea456fd000-7fea458fd000 ---p 0014a000 08:03 4822269                    /lib/libc-2.7.so
    7fea458fd000-7fea45900000 r-xp 0014a000 08:03 4822269                    /lib/libc-2.7.so
    7fea45900000-7fea45902000 rwxp 0014d000 08:03 4822269                    /lib/libc-2.7.so
    7fea45902000-7fea45907000 rwxp 7fea45902000 00:00 0 
    7fea45907000-7fea45923000 r-xp 00000000 08:03 4822265                    /lib/ld-2.7.so
    7fea45b02000-7fea45b04000 rwxp 7fea45b02000 00:00 0 
    7fea45b1f000-7fea45b22000 rwxp 7fea45b1f000 00:00 0 
    7fea45b22000-7fea45b24000 rwxp 0001b000 08:03 4822265                    /lib/ld-2.7.so
    7fff4db0f000-7fff4db24000 rwxp 7ffffffea000 00:00 0                      [stack]
    7fff4dbfe000-7fff4dc00000 r-xp 7fff4dbfe000 00:00 0                      [vdso]
    ffffffffff600000-ffffffffff601000 r-xp 00000000 00:00 0                  [vsyscall]
    Aborted
    Updating /boot/grub/grub.cfg ...

And it continued to upgrade without a glitch. The update should have failed.
Moreover, memory corruption isn't nice, which is another bug.