SSH server crashes under moderate/heavy load (General questions)

Hi,

I am using freesshd 1.0.8 as a server, but since it shares the same core as wodsshserver, I thought you might be interested in that bug which I already reported in freesshd forum:

I started using freesshd to replicate data between servers. For the moment, I only have 1 client machine, which is running continuoussly transfers via sFTP, using password authentication (not certificates, since it crashes the win2003 server). The transfers are done using a multithreaded application that automatically launches instances of WinSCP for the transfers. Each transfer consist of a few files and last a few seconds only, after which WinSCP logout from the server. I have currently configured it to run 8 concurrent threads (ie: 8 simultaneous sFTP sessions at any given time).

After 4-5 hours of running, freeSSHd crashed, and the DrWatson event log is attached below:

Event Type: Information
Event Source: DrWatson
Event Category: None
Event ID: 4097
Date: 27/09/2005
Time: 16:49:38
User: N/A
Computer: THUMBS3
Description:
The application, C:Program FilesfreeSSHdFreeSSHDService.exe, generated an application error The error occurred on 09/27/2005 @ 16:49:37.683 The exception generated was c0000005 at address 7C8224B2 (ntdll!ExpInterlockedPopEntrySListFault)

For more information, see Help and Support Center at http://go.microsoft.com/fwlink/events.asp.
Data:
0000: 0d 00 0a 00 0d 00 0a 00 ........
0008: 41 00 70 00 70 00 6c 00 A.p.p.l.
0010: 69 00 63 00 61 00 74 00 i.c.a.t.
0018: 69 00 6f 00 6e 00 20 00 i.o.n. .
0020: 65 00 78 00 63 00 65 00 e.x.c.e.
0028: 70 00 74 00 69 00 6f 00 p.t.i.o.
0030: 6e 00 20 00 6f 00 63 00 n. .o.c.
0038: 63 00 75 00 72 00 72 00 c.u.r.r.
0040: 65 00 64 00 3a 00 0d 00 e.d.:...
0048: 0a 00 20 00 20 00 20 00 .. . . .
0050: 20 00 20 00 20 00 20 00 . . . .
0058: 20 00 41 00 70 00 70 00 .A.p.p.
0060: 3a 00 20 00 43 00 3a 00 :. .C.:.
0068: 5c 00 50 00 72 00 6f 00 .P.r.o.
0070: 67 00 72 00 61 00 6d 00 g.r.a.m.
0078: 20 00 46 00 69 00 6c 00 .F.i.l.
0080: 65 00 73 00 5c 00 66 00 e.s..f.
0088: 72 00 65 00 65 00 53 00 r.e.e.S.
0090: 53 00 48 00 64 00 5c 00 S.H.d..
0098: 46 00 72 00 65 00 65 00 F.r.e.e.
00a0: 53 00 53 00 48 00 44 00 S.S.H.D.
00a8: 53 00 65 00 72 00 76 00 S.e.r.v.
00b0: 69 00 63 00 65 00 2e 00 i.c.e...
00b8: 65 00 78 00 65 00 20 00 e.x.e. .
00c0: 28 00 70 00 69 00 64 00 (.p.i.d.
00c8: 3d 00 37 00 39 00 32 00 =.7.9.2.
00d0: 29 00 0d 00 0a 00 20 00 )..... .
00d8: 20 00 20 00 20 00 20 00 . . . .
00e0: 20 00 20 00 20 00 57 00 . . .W.
00e8: 68 00 65 00 6e 00 3a 00 h.e.n.:.
00f0: 20 00 32 00 37 00 2f 00 .2.7./.
00f8: 30 00 39 00 2f 00 32 00 0.9./.2.
0100: 30 00 30 00 35 00 20 00 0.0.5. .
0108: 40 00 20 00 31 00 36 00 @. .1.6.
0110: 3a 00 34 00 39 00 3a 00 :.4.9.:.
0118: 33 00 37 00 2e 00 36 00 3.7...6.
0120: 38 00 33 00 0d 00 0a 00 8.3.....
0128: 20 00 20 00 20 00 20 00 . . . .
0130: 20 00 20 00 20 00 20 00 . . . .
0138: 45 00 78 00 63 00 65 00 E.x.c.e.
0140: 70 00 74 00 69 00 6f 00 p.t.i.o.
0148: 6e 00 20 00 6e 00 75 00 n. .n.u.
0150: 6d 00 62 00 65 00 72 00 m.b.e.r.
0158: 3a 00 20 00 63 00 30 00 :. .c.0.
0160: 30 00 30 00 30 00 30 00 0.0.0.0.
0168: 30 00 35 00 20 00 28 00 0.5. .(.
0170: 61 00 63 00 63 00 65 00 a.c.c.e.
0178: 73 00 73 00 20 00 76 00 s.s. .v.
0180: 69 00 6f 00 6c 00 61 00 i.o.l.a.
0188: 74 00 69 00 6f 00 6e 00 t.i.o.n.
0190: 29 00 0d 00 0a 00 0d 00 ).......
0198: 0a 00 2a 00 2d 00 2d 00 ..*.-.-.
01a0: 2d 00 2d 00 3e 00 20 00 -.-.>. .
01a8: 53 00 79 00 73 00 74 00 S.y.s.t.
01b0: 65 00 6d 00 20 00 49 00 e.m. .I.
01b8: 6e 00 66 00 6f 00 72 00 n.f.o.r.
01c0: 6d 00 61 00 74 00 69 00 m.a.t.i.
01c8: 6f 00 6e 00 20 00 3c 00 o.n. .<.
01d0: 2d 00 2d 00 2d 00 2d 00 -.-.-.-.
01d8: 2a 00 0d 00 0a 00 20 00 *..... .
01e0: 20 00 20 00 20 00 20 00 . . . .
01e8: 20 00 20 00 20 00 43 00 . . .C.
01f0: 6f 00 6d 00 70 00 75 00 o.m.p.u.
01f8: 74 00 65 00 72 00 20 00 t.e.r. .
0200: 4e

Arman,

since you seem to have 'stress test' application for this, can you send that app overhere to techsupport@weonlydo.com , so we can try to duplicate your issue?

Thanks.

Hi Guys,

I'm currently evaluating the latest SSHServer trial version for use as a test system for our SSH client, and am having a similar problem. It seems to run fine for up to about 8 hours, and then stops accepting connections. I am having it process about 5-10 connections a minute, each connection running for about 10 seconds (these are guestimates).

Any advice?

David.

David,

would it be possible to get your code so we can run it and produce same environment/effect as you experience?

Kreso

Hi Kreso,

I will have to check with the powers that be. Hopefully I can at least give you a cut-down version.

Until later and thanks,

David.

David,

That cut-down version will be very helpfully.
Even better will be that your cut-down version can duplicate that problem in your environment and then I hope that we will duplicate too so we can resolve problem.
Please send us your zipped project to: techsupport@weonlydo.com

Regards,
Alan