Re: [BUG] 2.6.38-rc2: Circular Locking Dependency

David Miller
2011-02-07T07:28:22Z

From: Knut Petersen <Knut_Petersen@t-online.de>
Date: Mon, 24 Jan 2011 10:25:55 +0100

> As I was hunting something different I found the following (potential)
> problem on an openSuSE 11.3 system with kernel 2.6.38-rc2.
> The message is triggerd by smpppd starting a dsl connection.
>
> Knut
>
>
> NET: Registered protocol family 24
>
> =======================================================
> [ INFO: possible circular locking dependency detected ]
> 2.6.38-rc2-kape #7
> -------------------------------------------------------
> pppd/2529 is trying to acquire lock:
> (&(&pch->downl)->rlock){+.....}, at: [<f814a634>] ppp_push+0x59/0x4a8
> [ppp_generic]
>
> but task is already holding lock:
> (&(&ppp->wlock)->rlock){+.-...}, at: [<f814ae1b>]
> ppp_xmit_process+0x19/0x451 [ppp_generic]
>
> which lock already depends on the new lock.

I've stared over this trace several times and can't figure out what
the problem is.

Paul, any idea?