Comment 11 for bug 57393

Please elevate the importance of this bug report! An average user would have no clue what to do in this situation, and so apt/synaptic/etc. should properly detect and catch the problem to avoid a segfault and suggest to the user what to do, if not offer the option to automatically delete and rebuild the cache files.

In my case, I experienced this problem seemingly out of the blue. After some investigation, I downloaded and installed the libc6-dbg manually with dpkg, in order to get a proper backtrace. It appears, however, that the mere act of installing the -dbg package solved the problem! I don't understand it. I even made a backup of the offending *pkgcache.bin files, and even after removing libc6-dbg and replacing the original cache files, I still can't reproduce the problem. Perhaps the segfault wasn't even related to the pkgcache.bin files, but this seemed the most likely scenario.

Unfortunately, all I could get of it while it was happening was an strace and this mostly useless backtrace:

# gdb --args /usr/bin/apt-get -- install audacity
GNU gdb 6.8-debian
This GDB was configured as "x86_64-linux-gnu"...
(no debugging symbols found)
(gdb) r
Starting program: /usr/bin/apt-get -- install audacity
(no debugging symbols found)
Reading package lists... Done
Building dependency tree
Reading state information... Done
Program received signal SIGSEGV, Segmentation fault.
0x00007fe2f313aae0 in strcmp () from /lib/libc.so.6
(gdb) bt
#0 0x00007fe2f313aae0 in strcmp () from /lib/libc.so.6
#1 0x00007fe2f30f43f4 in ?? () from /lib/libc.so.6
#2-15 same as above with random addresses
#16 0x00007fe2f30f4771 in qsort () from /lib/libc.so.6
#17 0x00000000004067e6 in ?? ()
#18 0x0000000000418e60 in ?? ()
#19 0x00007fe2f3ded6ca in CommandLine::DispatchArg ()
   from /usr/lib/libapt-pkg-libc6.7-6.so.4.6
#20 0x000000000040855b in ?? ()
#21 0x00007fe2f30de1c4 in __libc_start_main () from /lib/libc.so.6
#22 0x0000000000406539 in ?? ()
#23 0x00007ffffc2a8a58 in ?? ()
#24 0x0000000000000000 in ?? ()

I will work on trying to reproduce this problem, but no luck so far.