[Samba] FW: Weird Samba/CIFS behavior: client hangs

Kris Lou klou at themusiclink.net
Fri May 24 17:03:59 UTC 2019

Ohhhh, thanks for the link to that kernel bug.

6 months ago or so, I ran into something similar which mostly manifested as
a periodic hang with high iowait times that would resolve itself in a half
hour or so.  This would mostly affect those who are constantly working off
of fileshares -- opening spreadsheets directly from the share, etc.

I eventually "resolved" by downgrading to a 4.9 kernel, and haven't seen it
since (but haven't moved to newer kernels, either).  I thought it was a
kernel bug for sure, but never tied it directly to samba.  This is on
Debian, btw.

Also, from the most recent comment on that bug (

Note that if you are mounting with vers=1.0 (SMB1/CIFS) you will need
to either disable oplocks (see above) or use a recently proposed patch
from Ronnie to fix  credit handling for SMB1 oplocks.  The fix for
SMB1 oplock regression (which can cause hangs) will be in Linux kernel

Most people have disabled SMB1 by now, but I think that smbclient uses SMB1
by default.

Kris Lou
klou at themusiclink.net

On Fri, May 24, 2019 at 5:30 AM Aurélien Aptel via samba <
samba at lists.samba.org> wrote:

> I think a network trace would tell us for use whether the server is
> responding or not.
> You can follow the instruction here to make one:
> https://wiki.samba.org/index.php/Bug_Reporting#cifs.ko
> --
> Aurélien Aptel / SUSE Labs Samba Team
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