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

[Zhangxiaoxu]

Thanks a lot.

> Do you have processes in D state or processes using 100% CPU continuously?
Yes, if open the folder which is writing by itself and another client in windows explorer, the process will always in D state, and the CPU is higher.
I notice that, the client will send `change notify request`, then the smbd will receive a lot of message with code 0x310.
If the client receive the 'change notify response', it will send 'query directory request' to server.

> It might be that some message receiver does not pick up its messages at all.
Any idea about the case?

How do you think the solution:
keep the message queue length to 100 or more, and drop the other messages in 'queue_msg' function.


-----邮件原件-----
发件人: Volker Lendecke [mailto:Volker.Lendecke at SerNet.DE]
发送时间: 2017年5月11日 22:04
收件人: zhangxiaoxu 13123 (RD)
抄送: 'L.P.H. van Belle'; 'samba-technical at lists.samba.org'
主题: Re: 答复: [Samba] The memory maybe leak in samba 4.3.11

On Tue, May 09, 2017 at 02:59:51AM +0000, Zhangxiaoxu via samba-technical wrote:
> 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.

Do you have processes in D state or processes using 100% CPU continuously?

It might be that some message receiver does not pick up its messages at all.

Volker
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