Comment 9 for bug 401433

Also had dpkg hanging on rsyslog during upgrades.

I finally removed /etc/init/rsyslog* files and purged the package.
Trying to reinstall gives me the following trace:

$sudo strace -f dpkg -i /var/cache/apt/archives/rsyslog_4.2.0-2ubuntu4_i386.deb
...
[pid 11377] socket(PF_FILE, SOCK_STREAM, 0) = 3
[pid 11377] connect(3, {sa_family=AF_FILE, path=@"/com/ubuntu/upstart"}, 22) = 0
[pid 11377] fcntl64(3, F_GETFL) = 0x2 (flags O_RDWR)
[pid 11377] fcntl64(3, F_SETFL, O_RDWR|O_NONBLOCK) = 0
[pid 11377] fcntl64(3, F_GETFD) = 0
[pid 11377] fcntl64(3, F_SETFD, FD_CLOEXEC) = 0
[pid 11377] geteuid32() = 0
[pid 11377] rt_sigaction(SIGPIPE, {0x1, [PIPE], SA_RESTART}, {SIG_DFL, [], 0}, 8) = 0
[pid 11377] poll([{fd=3, events=POLLOUT}], 1, 0) = 1 ([{fd=3, revents=POLLOUT}])
[pid 11377] write(3, "\0", 1) = 1
[pid 11377] write(3, "AUTH EXTERNAL 30\r\n", 18) = 18
[pid 11377] poll([{fd=3, events=POLLIN}], 1, -1) = 1 ([{fd=3, revents=POLLIN}])
[pid 11377] read(3, "OK cdf044c963ff7a6d5ad8e06e4ac0b"..., 2048) = 37
[pid 11377] poll([{fd=3, events=POLLOUT}], 1, -1) = 1 ([{fd=3, revents=POLLOUT}])
[pid 11377] write(3, "BEGIN\r\n", 7) = 7
[pid 11377] poll([{fd=3, events=POLLIN|POLLOUT}], 1, -1) = 1 ([{fd=3, revents=POLLOUT}])
[pid 11377] writev(3, [{"l\1\2\1\f\0\0\0\1\0\0\0_\0\0\0\1\1o\0\23\0\0\0/com/ubu"..., 112}, {"\7\0\0\0rsyslog\0", 12}], 2) = 124
[pid 11377] gettimeofday({1254313423, 131137}, NULL) = 0
[pid 11377] poll([{fd=3, events=POLLIN}], 1, 25000) = 1 ([{fd=3, revents=POLLIN}])
[pid 11377] read(3, "l\2\1\1%\0\0\0\1\0\0\0\17\0\0\0\5\1u\0\1\0\0\0\10\1g\0\1o\0\0"..., 2048) = 69
[pid 11377] read(3, 0xbfcf90, 2048) = -1 EAGAIN (Resource temporarily unavailable)
[pid 11377] writev(3, [{"l\1\2\1\10\0\0\0\2\0\0\0q\0\0\0\1\1o\0 \0\0\0/com/ubu"..., 136}, {"\0\0\0\0\1\0\0\0", 8}], 2) = 144
[pid 11377] poll([{fd=3, events=POLLIN}], 1, -1
(waits here ...)

I'll try to purge again, restart and then install to check.