Hi Bjorn,

On Wed, 22 Aug 2012 11:02:52 -0700
Bjorn Helgaas [off-list ref] wrote:

On Wed, Aug 22, 2012 at 12:49 AM, Feng Tang [off-list ref] wrote:

quoted

Hi Fengguang,


On Wed, 22 Aug 2012 10:50:08 +0800
Fengguang Wu [off-list ref] wrote:

quoted

Feng,

quoted

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 [off-list ref]
AuthorDate: Wed May 30 23:15:41 2012 +0800
Commit:     Ingo Molnar [off-list ref]
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.

quoted

------------

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