rsync SIGBUS with 64-bit kernel

[Gabor Gombas]

rsync 3.2.3-2 dies with SIGBUS on a Raspberry Pi 4 running a 64-bit kernel:

    root@rpi:~# uname -a
    Linux rpi.home 5.4.51-v8+ #1333 SMP PREEMPT Mon Aug 10 16:58:35 BST 2020 aarch64 GNU/Linux
    root@rpi:~# mkdir /tmp/t
    root@rpi:~# rsync -a /bin/bash /tmp/t/
    Bus error
    root@rpi:~# rsync: connection unexpectedly closed (38 bytes received so far) [generator]
    rsync error: error in rsync protocol data stream (code 12) at io.c(228) [generator=3.2.3]

The error is caused by an unaligned access:

    write(4, "\4\200\0\7l variables.\n \n Option"..., 32776) = 32776
    --- SIGBUS {si_signo=SIGBUS, si_code=BUS_ADRALN, si_addr=0xf7d62acb} ---
    +++ killed by SIGBUS +++
    Bus error

Downgrading rsync to 3.2.2-2 from snapshot.raspbian.org makes the problem go away. The new rsync works fine on a Raspberry Pi 2 which has the same package versions installed.