Re: [BUG] 2.4.18pre6+ll: autofs+smbfs: processes in D state

From: Denis Vlasenko (vda@port.imtp.ilyichevsk.odessa.ua)
Date: Sat Feb 09 2002 - 11:19:16 EST


On 8 February 2002 18:55, Urban Widmark wrote:

> > I wanted to verify that mp3 was good before I got all of it,
> > so cd'ed to /mnt/auto/smb.host.dir, paused download,
> > copied incomplete file to Linux and tried to resume dl.
> > It failed (JetCar: "can't open file").
> > I rebooted NT box.
>
> This has nothing to do with the automounter.
>
> Rebooting the NT box with smbfs mounted probably made some process go to
> sleep for a long time, waiting for a reply or some network timeout.
>
> smbfs has an ugly and incorrect assumption that it will always get a reply
> to it's requests. And one process will block all others from sending any
> requests until it is done.

Note that NT box was rebooted, not shut down. I brought it back on and even
restarted download of unlucky mp3 (via NT downloader). Since NT box was
available on the network I thought smbfs will reestablish SMB connection, as
NFS do in similar scenario (server reboot).

> You may want to test the 2.4.17 patch on:
> http://www.hojdpunkten.ac.se/054/samba/index.html
>
> But that code is (very) experimental. It will allow multiple processes
> sending data, the processes will be in interruptible sleep and capable of
> timeout.
>
> Further down on that page there is a patch for 2.4.4 to make it poll()
> before reading and time-out. That is a smaller change and I have some good
> feedback on the 2.2 version of it.
>
> > Now I have some processes in D state. mc and ls hung trying to stat
> > /mnt/auto/smb.host.dir it seems. Ksymoopsed SysRq-T output below.
>
> They are all waiting for access to the smbfs "server" struct. None of them
> is the real problem.
>
> The process that is blocking the others is probably sleeping in
> tcp_data_wait(), and if so it is interruptible.

Hmmm, maybe... I tried to kill -KILL automounter, forgot to do that to
smbmount.

I will try to find reproducible scenario and then will try that patches.
Maybe you'll have to wait till Monday.

--
vda
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This archive was generated by hypermail 2b29 : Fri Feb 15 2002 - 21:00:26 EST