Re: [win-pv-devel] lost SRB in xenvbd

[Owen Smith <owen.smith@xxxxxxxxxx>]

The debug output looks a little different, but I think the underlying cause is 
the same to the bug I’m looking at the moment.

Basically, the response has been placed on the ring, but the Dpc is not pulling 
the response to complete the SRB (though I’m a little puzzled as how the 
Submitted queue is shown as empty)

Owen

From: Paul Durrant
Sent: 13 February 2017 17:31
To: 'Andreas Kinzler'; win-pv-devel@xxxxxxxxxxxxxxxxxxxx
Cc: Owen Smith
Subject: RE: [win-pv-devel] lost SRB in xenvbd

> -----Original Message-----
> From: win-pv-devel [mailto:win-pv-devel-bounces@xxxxxxxxxxxxxxxxxxxx] On
> Behalf Of Andreas Kinzler
> Sent: 13 February 2017 16:34
> To: win-pv-devel@xxxxxxxxxxxxxxxxxxxx
> Subject: [win-pv-devel] lost SRB in xenvbd
> 
> After days of debugging I find that xenvbd is causing hangs no matter if
> Xen 4.8.0, 4.7.1 or 4.5.1. In any case I see PdoResets
> 
> XENVBD|__PdoReset:Target[1] ====>
> XENVBD|PdoReset:Target[1] ====> (Irql=2)
> XENVBD|__PdoPauseDataPath:Target[1] : Waiting for 0 Submitted requests
> XENVBD|__PdoPauseDataPath:Target[1] : 0/0 Submitted requests left (0
> iterrations)
> XENVBD|PdoReset:Target[1] <==== (Irql=2)
> XENVBD|__PdoReset:Target[1] <====
> 
> The MSDN doc says a PDO reset is triggered if a SRB times out. In any
> hang I always see the following line:
> 
> XENVBD: FDO: Srbs            : 1 / 254 (12166611 Total)
> 

Owen,

  Does this tally with the issue you're looking at?

  Paul

>  From what I read in the driver source code this means that there is one
> SRB pending. But nothing is in the queues, rings, ... (see below). I
> assume that SRB has been lost somewhere?
> 
> Any help greatly appreciated.
> 
> BTW: Disabling discard caused the hang to appear quite rapidly (only one
> debug pass so far)
> 
> Regards Andreas
> 
> XENVBD: LOOKASIDE: REQUESTs: 0 / 83 (0 failed)
> XENVBD: LOOKASIDE: SEGMENTs: 0 / 888 (0 failed)
> XENVBD: LOOKASIDE: INDIRECTs: 0 / 0 (0 failed)
> XENVBD: QUEUE: Fresh     : 0 / 33
> XENVBD: QUEUE: Prepared  : 0 / 51
> XENVBD: QUEUE: Submitted : 0 / 36
> XENVBD: QUEUE: Shutdown  : 0 / 0
> XENVBD: FRONTEND: TargetId=1 DeviceId=832 BackendId=0
> XENVBD: FRONTEND: FrontendPath device/vbd/832
> XENVBD: FRONTEND: BackendPath  /local/domain/0/backend/vbd/2/832
> XENVBD: FRONTEND: TargetPath   data/scsi/target/1
> XENVBD: FRONTEND: State   : ENABLED
> XENVBD: FRONTEND: Caps    : CONNECTED
> XENVBD: FRONTEND: Features: PERSISTENT
> XENVBD: FRONTEND: DiskInfo: 100000000 @ 512 (512) 00000000
> XENVBD: GRANTER: CONNECTED ENABLED
> XENVBD: GRANTER: 1 / 889
> XENVBD: BLOCKRING: Requests  : 65968184 / 65968184
> XENVBD: BLOCKRING: SharedRing : 0xFFFFD001935A9000
> XENVBD: BLOCKRING: SharedRing : 65974354 / 65974355 - 65974354 /
> 65974355
> XENVBD: BLOCKRING: FrontRing  : 65974354 / 65974354 (32)
> XENVBD: BLOCKRING: Order      : 0
> XENVBD: BLOCKRING: Grants[0 ] : 0xFFFFE001E17B7B88 (33)
> XENVBD: NOTIFIER: Int / DPC : 56337743 / 64634483
> XENVBD: NOTIFIER: Channel : FFFFE001E17A76D0 (10)
> 
> 
> 
> _______________________________________________
> win-pv-devel mailing list
> win-pv-devel@xxxxxxxxxxxxxxxxxxxx
> https://lists.xenproject.org/cgi-bin/mailman/listinfo/win-pv-devel
_______________________________________________
win-pv-devel mailing list
win-pv-devel@xxxxxxxxxxxxxxxxxxxx
https://lists.xenproject.org/cgi-bin/mailman/listinfo/win-pv-devel