From: Bjorn Helgaas <bhelgaas@google.com>
To: Feng Tang <feng.tang@intel.com>
Cc: Fengguang Wu <fengguang.wu@intel.com>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
Steven Rostedt <rostedt@goodmis.org>, Avi Kivity <avi@redhat.com>,
Steven Rostedt <srostedt@redhat.com>,
LKML <linux-kernel@vger.kernel.org>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>,
Yinghai Lu <yinghai@kernel.org>,
linux-pci@vger.kernel.org
Subject: Re: pci_get_subsys: GFP_KERNEL allocations with IRQs disabled
Date: Wed, 22 Aug 2012 11:02:52 -0700 [thread overview]
Message-ID: <CAErSpo7HhdDi4EhbQZ-oZbsbGVvTfZW8MwKn7Tm+6B8jaQxLBg@mail.gmail.com> (raw)
In-Reply-To: <20120822154908.2e6ef3c0@feng-i7>
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?
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().
> ------------
> 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)
> {
> struct pci_dev *pdev;
> - struct pci_device_id *id;
> + struct pci_device_id id;
>
> /*
> * pci_find_subsys() can be called on the ide_setup() path,
> @@ -257,17 +257,12 @@ struct pci_dev *pci_get_subsys(unsigned int vendor, unsigned int device,
> if (unlikely(no_pci_devices()))
> return NULL;
>
> - id = kzalloc(sizeof(*id), GFP_KERNEL);
> - if (!id)
> - return NULL;
> - id->vendor = vendor;
> - id->device = device;
> - id->subvendor = ss_vendor;
> - id->subdevice = ss_device;
> -
> - pdev = pci_get_dev_by_id(id, from);
> - kfree(id);
> + 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.
> return pdev;
> }
next prev parent reply other threads:[~2012-08-22 18:03 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20120731121759.GA17822@localhost>
[not found] ` <5017D19B.5080806@redhat.com>
[not found] ` <1343738627.27983.30.camel@gandalf.stny.rr.com>
[not found] ` <5017D4AB.3090107@redhat.com>
[not found] ` <1343740419.27983.33.camel@gandalf.stny.rr.com>
[not found] ` <20120731234336.GA5526@localhost>
[not found] ` <1343778699.27983.70.camel@gandalf.stny.rr.com>
[not found] ` <20120731235705.GW2422@linux.vnet.ibm.com>
[not found] ` <1343779778.27983.73.camel@gandalf.stny.rr.com>
[not found] ` <20120801001811.GX2422@linux.vnet.ibm.com>
2012-08-01 0:43 ` pci_get_subsys: GFP_KERNEL allocations with IRQs disabled Fengguang Wu
2012-08-22 2:50 ` Fengguang Wu
2012-08-22 7:49 ` Feng Tang
2012-08-22 13:02 ` Fengguang Wu
2012-08-22 18:02 ` Bjorn Helgaas [this message]
2012-08-23 5:45 ` Feng Tang
2012-08-23 7:45 ` [PATCH 1/2] PCI: Use local parameter pci_device_id for pci_get_subsys/class() Feng Tang
2012-09-08 1:00 ` Yinghai Lu
2012-09-08 1:32 ` Yinghai Lu
2012-09-08 1:59 ` Greg Kroah-Hartman
2012-09-08 13:42 ` Fengguang Wu
2012-09-08 15:30 ` Yinghai Lu
2012-09-08 15:34 ` Feng Tang
2012-09-08 18:40 ` Yinghai Lu
2012-09-08 21:06 ` Bjorn Helgaas
2012-08-23 7:45 ` [PATCH 2/2] PCI: Remove the obsolete no_pci_devices() check Feng Tang
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