Re: sleeping functions called in invalid context during resume

[Stephen Hemminger <shemminger@osdl.org>]

On Wed, 15 Nov 2006 10:33:54 +0100
Ingo Molnar <mingo@elte.hu> wrote:

> 
> * Andrew Morton <akpm@osdl.org> wrote:
> 
> > >  [<ffffffff80215059>] vfs_write+0xce/0x174
> > >  [<ffffffff802159a5>] sys_write+0x45/0x6e
> > >  [<ffffffff802593de>] system_call+0x7e/0x83
> > > DWARF2 unwinder stuck at system_call+0x7e/0x83
> > > 
> > > Leftover inexact backtrace:
> > 
> > Could mean that someone somewhere forgot to release a spinlock.
> > 
> > Ingo had a patch which would find the culprit (preempt-tracing.patch).
> > 
> > Does it still live?
> 
> if it's really a spinlock/rwlock release that was missed, then i've got 
> good news: we already have that debugging infrastructure, it's called 
> lockdep :-)
> 
> The patch below makes use of that capability of lockdep for all 
> stackdumps that are printed to the console. Stephen, please apply this 
> patch, enable CONFIG_PROVE_LOCKING and try to trigger another message. 
> 
> 	Ingo

I tried but with CONFIG_PROVE_LOCKING, resume gets stuck in an infinite
loop backtracing to the console.  Unfortunately, the serial console isn't up
at that point so it it isn't capturable.