Hi Raghavendra/Venky,
Gentle reminder. Oleksander (post-factum) confirmed that their
production setup has been running with this patch included since
sometime and had no issues. Shall we consider merging this patch if
there are no review comments?
Thanks,
Soumya
On 03/09/2016 09:16 PM, Kotresh Hiremath Ravishankar wrote:
Hi All,
The following patch is sent to address changelog rpc mem-leak issues.
The fix is intricate and needs lot of testing before taking in. Please
review the same.
http://review.gluster.org/#/c/13658/1
Thanks and Regards,
Kotresh H R
----- Original Message -----
From: "Venky Shankar" <vshankar@xxxxxxxxxx>
To: "Raghavendra G" <raghavendra@xxxxxxxxxxx>
Cc: "Kotresh Hiremath Ravishankar" <khiremat@xxxxxxxxxx>, "Gluster Devel" <gluster-devel@xxxxxxxxxxx>
Sent: Monday, March 7, 2016 3:52:13 PM
Subject: Re: Cores generated with ./tests/geo-rep/georep-basic-dr-tarssh.t
On Fri, Mar 04, 2016 at 02:02:32PM +0530, Raghavendra G wrote:
On Thu, Mar 3, 2016 at 6:26 PM, Kotresh Hiremath Ravishankar <
khiremat@xxxxxxxxxx> wrote:
Hi,
Yes, with this patch we need not set conn->trans to NULL in
rpc_clnt_disable
While [1] fixes the crash, things can be improved in the way how changelog
is using rpc.
1. In the current code, there is an rpc_clnt object leak during disconnect
event.
Just for the record (as I couldn't find this information while building up
rpc infrastructure in changelog):
Unref rpc-clnt object after calling rpc_clnt_disable() in notify() upon
RPC_CLNT_DISCONNECT. Free up 'mydata' in notify() upon RPC_CLNT_DESTROY.
2. Also, freed "mydata" of changelog is still associated with rpc_clnt
object (corollary of 1), though change log might not get any events with
"mydata" (as connection is dead).
I've discussed with Kotresh about changes needed, offline. So, following
are the action items.
1. Soumya's patch [2] is valid and is needed for 3.7 branch too.
2. [2] can be accepted. However, someone might want to re-use an rpc object
after disabling it, like introducing a new api rpc_clnt_enable_again
(though no of such use-cases is very less). But [2] doesn't allow it. The
point is as long as rpc-clnt object is alive, transport object is alive
(though disconnected) and we can re-use it. So, I would prefer not to
accept it.
3. Kotresh will work on new changes to make sure changelog makes correct
use of rpc-clnt.
[1] http://review.gluster.org/#/c/13592
[2] http://review.gluster.org/#/c/1359
regards,
Raghavendra.
Thanks and Regards,
Kotresh H R
----- Original Message -----
From: "Soumya Koduri" <skoduri@xxxxxxxxxx>
To: "Kotresh Hiremath Ravishankar" <khiremat@xxxxxxxxxx>, "Raghavendra
G" <raghavendra@xxxxxxxxxxx>
Cc: "Gluster Devel" <gluster-devel@xxxxxxxxxxx>
Sent: Thursday, March 3, 2016 5:06:00 PM
Subject: Re: Cores generated with
./tests/geo-rep/georep-basic-dr-tarssh.t
On 03/03/2016 04:58 PM, Kotresh Hiremath Ravishankar wrote:
[Replying on top of my own reply]
Hi,
I have submitted the below patch [1] to avoid the issue of
'rpc_clnt_submit'
getting reconnected. But it won't take care of memory leak problem
you
were
trying to fix. That we have to carefully go through all cases and fix
it.
Please have a look at it.
Looks good. IIUC, with this patch, we need not set conn->trans to NULL
in 'rpc_clnt_disable()'. Right? If yes, then it takes care of memleak
as
the transport object shall then get freed as part of
'rpc_clnt_trigger_destroy'.
http://review.gluster.org/#/c/13592/
Thanks and Regards,
Kotresh H R
----- Original Message -----
From: "Kotresh Hiremath Ravishankar" <khiremat@xxxxxxxxxx>
To: "Soumya Koduri" <skoduri@xxxxxxxxxx>
Cc: "Raghavendra G" <raghavendra@xxxxxxxxxxx>, "Gluster Devel"
<gluster-devel@xxxxxxxxxxx>
Sent: Thursday, March 3, 2016 3:39:11 PM
Subject: Re: Cores generated with
./tests/geo-rep/georep-basic-dr-tarssh.t
Hi Soumya,
I tested the lastes patch [2] on master where your previous patch
[1]
in
merged.
I see crashes at different places.
1. If there are code paths that are holding rpc object without
taking
ref
on
it, all those
code path will crash on invoking rpc submit on that object as
rpc
object
would have freed
by last unref on DISCONNECT event. I see this kind of use-case
in
chagnelog rpc code.
Need to check on other users of rpc.
Agree. We should fix all such code-paths. Since this seem to be an
intricate fix, shall we take these patches only in master branch and
not
in 3.7 release for now till we fix all such paths as we encounter?
2. And also we need to take care of reconnect timers that are being
set
and
are re-tried to
connect back on expiration. In those cases also, we might crash
as rpc
object would have freed.
Your patch addresses this..right?
Thanks,
Soumya
[1] http://review.gluster.org/#/c/13507/
[2] http://review.gluster.org/#/c/13587/
Thanks and Regards,
Kotresh H R
----- Original Message -----
From: "Soumya Koduri" <skoduri@xxxxxxxxxx>
To: "Raghavendra G" <raghavendra@xxxxxxxxxxx>, "Kotresh Hiremath
Ravishankar" <khiremat@xxxxxxxxxx>
Cc: "Gluster Devel" <gluster-devel@xxxxxxxxxxx>
Sent: Thursday, March 3, 2016 12:24:00 PM
Subject: Re: Cores generated with
./tests/geo-rep/georep-basic-dr-tarssh.t
Thanks a lot Kotresh.
On 03/03/2016 08:47 AM, Raghavendra G wrote:
Hi Soumya,
Can you send a fix to this regression on upstream master too? This
patch
is merged there.
I have submitted below patch.
http://review.gluster.org/#/c/13587/
Kindly review the same.
Thanks,
Soumya
regards,
Raghavendra
On Tue, Mar 1, 2016 at 10:34 PM, Kotresh Hiremath Ravishankar
<khiremat@xxxxxxxxxx <mailto:khiremat@xxxxxxxxxx>> wrote:
Hi Soumya,
I analysed the issue and found out that crash has happened
because
of the patch [1].
The patch doesn't set transport object to NULL in
'rpc_clnt_disable'
but instead does it on
'rpc_clnt_trigger_destroy'. So if there are pending rpc
invocations
on the rpc object that
is disabled (those instances are possible as happening now in
changelog), it will trigger a
CONNECT notify again with 'mydata' that is freed causing a
crash.
This happens because
'rpc_clnt_submit' reconnects if rpc is not connected.
rpc_clnt_submit (...) {
...
if (conn->connected == 0) {
ret = rpc_transport_connect
(conn->trans,
conn->config.remote_port);
}
...
}
Without your patch, conn->trans was set NULL and hence
CONNECT
fails
not resulting with
CONNECT notify call. And also the cleanup happens in failure
path.
So the memory leak can happen, if there is no try for rpc
invocation
after DISCONNECT.
It will be cleaned up otherwise.
[1] http://review.gluster.org/#/c/13507/
Thanks and Regards,
Kotresh H R
----- Original Message -----
> From: "Kotresh Hiremath Ravishankar" <khiremat@xxxxxxxxxx
<mailto:khiremat@xxxxxxxxxx>>
> To: "Soumya Koduri" <skoduri@xxxxxxxxxx
> <mailto:skoduri@xxxxxxxxxx>>
> Cc: avishwan@xxxxxxxxxx <mailto:avishwan@xxxxxxxxxx>,
"Gluster
Devel" <gluster-devel@xxxxxxxxxxx
<mailto:gluster-devel@xxxxxxxxxxx>>
> Sent: Monday, February 29, 2016 4:15:22 PM
> Subject: Re: Cores generated with
./tests/geo-rep/georep-basic-dr-tarssh.t
>
> Hi Soumya,
>
> I just tested that it is reproducible only with your patch
both
in master and
> 3.76 branch.
> The geo-rep test cases are marked bad in master. So it's
not hit
in master.
> rpc is introduced
> in changelog xlator to communicate to applications via
libgfchangelog.
> Venky/Me will check
> why is the crash happening and will update.
>
>
> Thanks and Regards,
> Kotresh H R
>
> ----- Original Message -----
> > From: "Soumya Koduri" <skoduri@xxxxxxxxxx
<mailto:skoduri@xxxxxxxxxx>>
> > To: avishwan@xxxxxxxxxx <mailto:avishwan@xxxxxxxxxx>,
> > "kotresh"
<khiremat@xxxxxxxxxx <mailto:khiremat@xxxxxxxxxx>>
> > Cc: "Gluster Devel" <gluster-devel@xxxxxxxxxxx
<mailto:gluster-devel@xxxxxxxxxxx>>
> > Sent: Monday, February 29, 2016 2:10:51 PM
> > Subject: Cores generated with
./tests/geo-rep/georep-basic-dr-tarssh.t
> >
> > Hi Aravinda/Kotresh,
> >
> > With [1], I consistently see cores generated with the
> > test
> > './tests/geo-rep/georep-basic-dr-tarssh.t' in
> > release-3.7
branch. From
> > the cores, looks like we are trying to dereference a
> > freed
> > changelog_rpc_clnt_t(crpc) object in
changelog_rpc_notify().
Strangely
> > this was not reported in master branch.
> >
> > I tried debugging but couldn't find any possible
suspects. I
request you
> > to take a look and let me know if [1] caused any
regression.
> >
> > Thanks,
> > Soumya
> >
> > [1] http://review.gluster.org/#/c/13507/
> >
>
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Raghavendra G
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