lkml.org 
[lkml]   [2012]   [Aug]   [23]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: pci_get_subsys: GFP_KERNEL allocations with IRQs disabled
Hi Bjorn,

On Wed, 22 Aug 2012 11:02:52 -0700
Bjorn Helgaas <bhelgaas@google.com> wrote:

> On Wed, Aug 22, 2012 at 12:49 AM, Feng Tang <feng.tang@intel.com> wrote:
> > Hi Fengguang,
> >
> >
> > On Wed, 22 Aug 2012 10:50:08 +0800
> > Fengguang Wu <fengguang.wu@intel.com> wrote:
> >
> >> Feng,
> >>
> >> > I think it's pci_get_subsys() triggered this assert:
> >> >
> >> > /*
> >> > * Oi! Can't be having __GFP_FS allocations with IRQs disabled.
> >> > */
> >> > if (DEBUG_LOCKS_WARN_ON(irqs_disabled_flags(flags)))
> >> > return;
> >>
> >> It's bisected down to this commit:
> >>
> >> commit 55c844a4dd16a4d1fdc0cf2a283ec631a02ec448
> >> Author: Feng Tang <feng.tang@intel.com>
> >> AuthorDate: Wed May 30 23:15:41 2012 +0800
> >> Commit: Ingo Molnar <mingo@kernel.org>
> >> CommitDate: Wed Jun 6 12:03:23 2012 +0200
> >>
> >> x86/reboot: Fix a warning message triggered by stop_other_cpus()
> >>
> >> Thanks,
> >> Fengguang
> >
> > Thanks for the bisection.
> >
> > Revert my commit should be a solution, but can we simply make the pci_device_id
> > a local on stack one instead of using sleepable kmalloc for it, as this
> > sounds fragile when pci_get_subsys get called in a late system reboot stage?
>
> I think this is a great idea. Can you make this a real patch, with a
> changelog and Signed-off-by?

Thanks and will do.

>
> We should also remove the obsolete comment about early boot. I'm not
> sure the no_pci_devices() check is needed, either. And we can make
> the same simplification in pci_get_class().

Will check the no_pci_devices() part, and try to make it a separate
patch for easy reverting in case of error.

>
> > ------------
> > diff --git a/drivers/pci/search.c b/drivers/pci/search.c
> > index 993d4a0..e5ccede 100644
> > --- a/drivers/pci/search.c
> > +++ b/drivers/pci/search.c
> > @@ -246,7 +246,7 @@ struct pci_dev *pci_get_subsys(unsigned int vendor, unsigned int device,
> > struct pci_dev *from)
> > {
> > + id.vendor = vendor;
> > + id.device = device;
> > + id.subvendor = ss_vendor;
> > + id.subdevice = ss_device;
> >
> > + pdev = pci_get_dev_by_id(&id, from);
>
> No need for "pdev" here, since we don't have to free anything.

ok, will directly return it.

Thanks,
Feng


\
 
 \ /
  Last update: 2012-08-23 08:41    [W:0.074 / U:0.820 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site