答复: [Samba] The memory maybe leak in samba 4.3.11

Tue May 9 02:59:51 UTC 2017

Hi,
Thanks a lot.

Use the valgrind, we found the stack of the malloc as below, so, maybe it is not memory leak.
    ==2796353== 36,334,440 bytes in 100,929 blocks are still reachable in loss record 774 of 774
    ==2796353==    at 0x4C2AB80: malloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
    ==2796353==    by 0x953B88F: ??? (in /usr/lib/x86_64-linux-gnu/samba/libmessages-dgm.so.0)
    ==2796353==    by 0x953BCA0: ??? (in /usr/lib/x86_64-linux-gnu/samba/libmessages-dgm.so.0)
    ==2796353==    by 0x953C342: unix_msg_send (in /usr/lib/x86_64-linux-gnu/samba/libmessages-dgm.so.0)
    ==2796353==    by 0x953E3B6: messaging_dgm_send (in /usr/lib/x86_64-linux-gnu/samba/libmessages-dgm.so.0)
    ==2796353==    by 0x71732FF: messaging_send_iov_from (in /usr/lib/x86_64-linux-gnu/libsmbconf.so.0)
    ==2796353==    by 0x716E1BA: ??? (in /usr/lib/x86_64-linux-gnu/libsmbconf.so.0)
    ==2796353==    by 0x716E869: ??? (in /usr/lib/x86_64-linux-gnu/libsmbconf.so.0)
    ==2796353==    by 0x716EA91: ??? (in /usr/lib/x86_64-linux-gnu/libsmbconf.so.0)
    ==2796353==    by 0x7171207: ctdbd_migrate (in /usr/lib/x86_64-linux-gnu/libsmbconf.so.0)
    ==2796353==    by 0x716BD6E: ??? (in /usr/lib/x86_64-linux-gnu/libsmbconf.so.0)
        ==2796353==    by 0xAE6692F: ??? (in /usr/lib/x86_64-linux-gnu/samba/libdbwrap.so.0)

Ifound the sendmsg is always failed because erron=EINTR, but smbd also need to malloc for the new msgs, so the res of the smbd grows up quickly.

I add some code in unix_dgram_send_job, just send 10 times if sendmsg faild with EINTR, the res will not grows up anymore.
Another, keep the max queue length to 100 also work well.

I don’t know whether it is suitable for the process, also, I want to know why sendmsg return EINTR.
Could you give us some suggestion about the case.

Br,
Zhang Xiaoxu.

-----邮件原件-----
发件人: L.P.H. van Belle [mailto:belle at bazuin.nl]
发送时间: 2017年5月4日 20:53
收件人: samba at lists.samba.org
主题: Re: [Samba] The memory maybe leak in samba 4.3.11

Oeps, sorry wrong one.

There where multiple fixes.

https://wiki.samba.org/index.php/Samba_4.4_Features_added/changed
BUG #12377: vfs_glusterfs: Fix a memory leak in connect path.

https://wiki.samba.org/index.php/Samba_4.5_Features_added/changed
BUG #12485: ctdbd_conn: Fix a resource leak.

https://wiki.samba.org/index.php/Samba_4.6_Features_added/changed
## BUG #12624: lib/pthreadpool: Fix a memory leak.

Greetz,

Louis

> -----Oorspronkelijk bericht-----
> Van: samba-technical
> [mailto:samba-technical-bounces at lists.samba.org] Namens Zhangxiaoxu
> via samba-technical
> Verzonden: donderdag 4 mei 2017 14:42
> Aan: 'bugzilla-maintenance at samba.org';
> 'samba-technical at lists.samba.org'
> Onderwerp: The memory maybe leak in samba 4.3.11
>
> Hi,
>
> SCENE:
> Client A and Client B write data to an share.
> Client B open the share with windows explorer.
>
> Problem:
> The RES of smbd grows quickly.
>      $ top
> PID USER      PR  NI    VIRT    RES    SHR S  %CPU %MEM
> TIME+ COMMAND        CODE    DATA
> 2913029 nobody    20   0 1664536 1.204g  16608 D   0.0  1.3
> 5:09.21 smbd            64        1318580
>
> Process 2913029 is the connection of client B.
> The DATA also grows quickly.
>
> Use smbcontrol, we found smbd process not talloc so much memory.
> $ smbcontrol 2913029 pool-usage
> full talloc report on 'null_context' (total  92353 bytes in
> 1274 blocks)
>
>   From logs, we found there a lot of 0x310(maybe
> MSG_PVFS_NOTIFY) message from the ctdb.
>
> Environment:
> Ubuntu 14.04
> Samba 4.3.11
> Windows 7 Client
>
> Configuration:
> clustering = yes
>     ctdbd socket = /var/run/ctdb/ctdbd.socket
>    max protocol = SMB3
>    large readwrite = yes
>    idmap config *:range = 1000000-1999999
>    log level = 2
>    use sendfile = yes
>    store dos attributes = yes
>    acl_xattr:ignore system acls = yes
>    aio read size = 1024
>    deadtime = 10
>
> Is this an exist problem?
> Could you give us some suggestion about how to find the root cause
> about the problem.
>
> Br,
> Zhang Xiaoxu.
> --------------------------------------------------------------
> --------------------------------------------------------------
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