[BackupPC-users] backuppc hangs when rsync XferMethod is used for client with openssh-6.0

[Martin J. <mar...@gm...>]

Hi,

few days ago I've upgraded my box from openssh-5.9 to openssh-6.0 and
since then I've seen many hangs from backuppc (actually no full backup
was completed, e.g. still running after 24hours, usually it finishes
in ~ 3 hours - 60GB)

rsync --server was running fine (I was able to rsync whole disk with it)

perl process was stuck in select() call:

pid 5553: /usr/bin/perl /usr/bin/BackupPC_dump -v -f 127.0.0.1

# strace -p 5553
Process 5553 attached
select(16, [10], NULL, [10], NULL^CProcess 5553 detached

# gdb --pid=5553
(gdb) bt
#0  0x00007fb20ba3f6e3 in select () from /lib64/libc.so.6
#1  0x00007fb20cb69465 in Perl_pp_sselect () from /usr/lib64/libperl.so.5.14
#2  0x00007fb20cb1f306 in Perl_runops_standard () from
/usr/lib64/libperl.so.5.14
#3  0x00007fb20cac0d6a in perl_run () from /usr/lib64/libperl.so.5.14
#4  0x0000000000400e89 in main ()

Usually it rsynced 24MB to new backup, sometimes more, but e.g.
XferLogLevel and --verbose haven't changed that.

Looking at openssh changelog I suspect this 2 changes:
https://bugzilla.mindrot.org/show_bug.cgi?id=1859
https://bugzilla.mindrot.org/show_bug.cgi?id=1943
but it could be something completly different, but now after downgrade
back to 5.9 I've rsynced 2,7G to new sofar and it's still running.

I'll try to narrow this a bit more (even bisect openssh if needed),
but wanted to report it here asap so people don't need to debug perl
and other stuff like I did (not expecting openssh to be the cause). Or
maybe someone already knows about better work around with -W or
something which should be added to default BackupPC config..

Cheers,