Date: Mon, 18 Nov 2002 16:09:58 -0500 (EST) From: John Baldwin <jhb@FreeBSD.org> To: John Baldwin <jhb@FreeBSD.org> Cc: Kris Kennaway <kris@obsecurity.org>, current@FreeBSD.ORG, tanimura@FreeBSD.ORG, Alfred Perlstein <alfred@FreeBSD.ORG> Subject: Re: Lock order reversals in sys_pipe.c and kern_sig.c Message-ID: <XFMail.20021118160958.jhb@FreeBSD.org> In-Reply-To: <XFMail.20021118154310.jhb@FreeBSD.org>
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On 18-Nov-2002 John Baldwin wrote:
>
> On 18-Nov-2002 Alfred Perlstein wrote:
>> * Kris Kennaway <kris@obsecurity.org> [021118 12:01] wrote:
>>> On Mon, Nov 18, 2002 at 11:39:01AM -0800, Alfred Perlstein wrote:
>>>
>>> > Well now they are, I will investigate as time permits.
>>>
>>> Thanks.
>>>
>>> > I'm still in a holding pattern about adding more debugging info to
>>> > lockd now that we're in release candidate mode. I may ask for a
>>> > branch to be done, but i'm not sure yet.
>>>
>>> Feel free to give me non-committed patches to test :-)
>>
>> GRR, witless always gives me the locations of the correct lock
>> order, never the locations of the incorrect ones, so here, try this
>> and give me a backtrace, it should nail you with extreme prejudice
>> when you get what i think is the wrong order:
>
> This is why there is a static lock-order list that you can add to.
> For example:
>
> Index: subr_witness.c
> ===================================================================
> RCS file: /usr/cvs/src/sys/kern/subr_witness.c,v
> retrieving revision 1.130
> diff -u -r1.130 subr_witness.c
> --- subr_witness.c 11 Nov 2002 16:36:20 -0000 1.130
> +++ subr_witness.c 18 Nov 2002 20:42:35 -0000
> @@ -205,6 +205,9 @@
> { "uidinfo hash", &lock_class_mtx_sleep },
> { "uidinfo struct", &lock_class_mtx_sleep },
> { NULL, NULL },
> + { "sigio lock", &lock_class_mtx_sleep },
> + { "pipe mutex", &lock_class_mtx_sleep },
> + { NULL, NULL },
> /*
> * spin locks
> */
At some point I may add a userland function that allows you to specify
an order to witness at runtime.
--
John Baldwin <jhb@FreeBSD.org> <>< http://www.FreeBSD.org/~jhb/
"Power Users Use the Power to Serve!" - http://www.FreeBSD.org/
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