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Date: Thu, 29 Nov 2007 16:42:07 -0800
From: Andrew Morton <akpm@linux-foundation.org>
To: Bjorn Helgaas <bjorn.helgaas@hp.com>
Cc: jirislaby@gmail.com, matthew@wil.cx, linux-kernel@vger.kernel.org,
       gregkh@suse.de, linux-usb-devel@lists.sourceforge.net,
       linux-pm@lists.linux-foundation.org, drzeus@drzeus.cx
Subject: Re: WARNING: at kernel/resource.c:189 __release_resource
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On Thu, 29 Nov 2007 16:40:37 -0700
Bjorn Helgaas <bjorn.helgaas@hp.com> wrote:

> On Monday 26 November 2007 11:05:38 pm Andrew Morton wrote:
> > On Thu, 22 Nov 2007 22:41:16 +0100 Jiri Slaby <jirislaby@gmail.com> wrote:
> > > Ok, I hit the bug, suspend of 00:06 device complains about it:
> > > WARNING: at .../kernel/resource.c:185 __release_resource()
> > > 
> > > Call Trace:
> > >  [<ffffffff8023f7b5>] release_resource+0xb5/0xf0
> > >  [<ffffffff8036cda0>] pnp_release_resources+0x70/0x130
> > >  [<ffffffff8036db85>] pnp_stop_dev+0x45/0x90
> > >  [<ffffffff8036c942>] pnp_bus_suspend+0x92/0xb0
> > >  [<ffffffff803b9f73>] suspend_device+0x113/0x180
> > >  [<ffffffff803ba330>] device_suspend+0x200/0x320
> > >  [<ffffffff80266905>] suspend_devices_and_enter+0xa5/0x170
> > >  [<ffffffff80266bd9>] enter_state+0x209/0x270
> > >  [<ffffffff80266cef>] state_store+0xaf/0xf0
> > >  [<ffffffff8032ca67>] kobj_attr_store+0x17/0x20
> > >  [<ffffffff802e459e>] sysfs_write_file+0xce/0x140
> > >  [<ffffffff80299cc7>] vfs_write+0xc7/0x170
> > >  [<ffffffff8029a360>] sys_write+0x50/0x90
> > >  [<ffffffff8020bcde>] system_call+0x7e/0x83
> > > 
> > > # LANG=en ll /sys/devices/pnp0/00:06/
> > > total 0
> > > lrwxrwxrwx 1 root root    0 Nov 22 22:35 driver -> ../../../bus/pnp/drivers/serial
> > > -r--r--r-- 1 root root 4096 Nov 22 22:35 id
> > > -r--r--r-- 1 root root 4096 Nov 22 22:35 options
> > > drwxr-xr-x 2 root root    0 Nov 22 22:35 power
> > > -rw-r--r-- 1 root root 4096 Nov 22 22:35 resources
> > > lrwxrwxrwx 1 root root    0 Nov 22 22:35 subsystem -> ../../../bus/pnp
> > > drwxr-xr-x 3 root root    0 Nov 22 22:35 tty
> > > -rw-r--r-- 1 root root 4096 Nov 22 22:35 uevent
> > 
> > I suppose that's a genuine leak, presumably in 8250_pnp.
> 
> We used to have only the serial driver resource reservation.  We now
> have an additional 00:06 resource that is the parent of the serial
> resource, e.g.,
> 
>   03f8-03ff : 00:06
>     03f8-03ff : serial
> 
> I think this problem happens because pnp_bus_suspend() calls
> serial_pnp_suspend(), which suspends the driver but does nothing
> with the resources.  Then it calls pnp_stop_dev(), which releases
> the 00:06 resource, which still has a serial child resource.
> 
> The corresponding PCI code in pci_device_suspend() does not do
> any generic device disable or resource release.  I don't know
> why PNP disables the device on suspend.  I glanced through the
> ACPI spec but didn't see a requirement for it.  Maybe Pierre [1]
> remembers.
> 
> Maybe we could either remove the pnp_{stop,start}_dev() calls
> from the suspend/resume path, or move the PNP resource management
> out of pnp_{start,stop}_dev().
> 
> Bjorn
> 
> [1] http://lkml.org/lkml/2005/11/30/39

So was this particular problem caused/exposed by
pnp-request-ioport-and-iomem-resources-used-by-active-devices.patch, or is
it in mainline?

Thanks.