Re: 2.6.17-rc5-mm3

From: Dave Jones
Date: Mon Jun 05 2006 - 17:01:23 EST


On Mon, Jun 05, 2006 at 01:53:54PM -0700, Andrew Morton wrote:

> > > > Try reverting debug-shared-irqs.patch, or disable the sound driver?
> > > Will turn off the sound driver, and see what happens.
> > Win! It now boots.
> So does Windows 95.

Hey, it's my turn to play "optimist" today. :)

> > I blew it up really easy with a socket-fuzzer though.
> > (http://people.redhat.com/davej/sfuzz.c)
>
> But it kept running OK, yes?

Yep, still ticking along (for now).

> > [ 874.865028] ======================================
> > [ 874.943738] [ BUG: bad unlock ordering detected! ]
> > [ 875.002919] --------------------------------------
> > [ 875.062134] sfuzz/23915 is trying to release lock (&sctp_port_alloc_lock) at:
> > [ 875.149619] [<d128ed4e>] sctp_get_port_local+0xd0/0x285 [sctp]
> > [ 875.222636] but the next lock to release is:
> > [ 875.276019] (&sctp_port_hashtable[i].lock){-...}, at: [<d128ed0e>] sctp_get_port_local+0x90/0x285 [sctp]
> > [ 875.393031]
> > [ 875.393032] other info that might help us debug this:
> > [ 875.476583] 1 locks held by sfuzz/23915:
> > [ 875.526247] #0: (&sctp_port_alloc_lock){-...}, at: [<d128ecd9>] sctp_get_port_local+0x5b/0x285 [sctp]
> > [ 875.641621]
> > [ 875.641623] stack backtrace:
> > [ 875.699891] [<c0104966>] show_trace_log_lvl+0x54/0xfd
> > [ 875.764425] [<c0104f1a>] show_trace+0xd/0x10
> > [ 875.819622] [<c010502f>] dump_stack+0x19/0x1b
> > [ 875.875924] [<c013b4af>] lockdep_release+0x150/0x2d1
> > [ 875.939610] [<c032341e>] _spin_unlock+0x16/0x20
> > [ 875.998171] [<d128ed4e>] sctp_get_port_local+0xd0/0x285 [sctp]
> > [ 876.072345] [<d128efd4>] sctp_do_bind+0x9a/0x158 [sctp]
> > [ 876.139315] [<d128f0ce>] sctp_autobind+0x3c/0x44 [sctp]
> > [ 876.206310] [<d129253d>] sctp_inet_listen+0xe9/0x139 [sctp]
> > [ 876.277539] [<c02c20af>] sys_listen+0x4a/0x65
> > [ 876.334730] [<c02c308d>] sys_socketcall+0x98/0x186
> > [ 876.397175] [<c03239cb>] syscall_call+0x7/0xb
>
> This is a really really fussy "BUG", IMO. So we undid the locks in an
> inappropriate order - big deal.
>
> But often these _are_ things which we should tune up, as an efficiency
> thing, so it is interesting to hear about them. But calling it a "BUG" is
> a bit alarmist.

Maybe so, but it's still pretty grotty though.

Dave

--
http://www.codemonkey.org.uk
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