Re: Kernel oops from pci_disable_msi

[Marek Vasut <marex@denx.de>]

Dear Bjørn Erik Nilsen,

> On Tue, 2013-11-19 at 12:39 +0100, Bjørn Erik Nilsen wrote:
> > On Tue, 2013-11-19 at 12:24 +0100, Marek Vasut wrote:
> > > Dear Jingoo Han,
> > > 
> > > > On Tuesday, November 19, 2013 6:03 AM, Bjorn Helgaas wrote:
> > > > > On Mon, Nov 18, 2013 at 2:01 PM, Bjorn Helgaas <bhelgaas@google.com> 
wrote:
> > > > >> On Mon, Nov 18, 2013 at 6:53 AM, Bjørn Erik Nilsen
> > > > >> <ben@datarespons.no>
> > > 
> > > wrote:
> > > > >>> I just hit an kernel oops related to PCI (in
> > > > >>> dw_msi_teardown_irq()/clear_irq() (pcie-designware))
> > > > >>> 
> > > > >>> Linux version 3.12.0-next-20131105 (bnilsen@bnilsen) (gcc version
> > > > >>> 4.7.2 (GCC) )
> > > > >>> 
> > > > >>> Problem seem to be dereferencing a null pointer returned from
> > > > >>> irq_desc_get_msi_desc(desc) (see attached backtrace).
> > > > >> 
> > > > >> Included oops inline for ease of viewing/searching.  Jingooo, I
> > > > >> assume you'll investigate this.  Let me know if otherwise.
> > > > 
> > > > (+cc Marek Vasut, Pratyush Anand, Kishon Vijay Abraham I,
> > > > 
> > > >        Mohit KUMAR DCG, Ajay KHANDELWAL, Tim Harvey)
> > > > 
> > > > Sorry, I will not investigate this.
> > > > 
> > > > Bjørn Erik Nilsen,
> > > > 
> > > > Would you let us know the ARM platform and LAN card?
> > > > If you let us know them, one of these pcie-designware related
> > > > people would reproduce and look at the issue.
> > > > 
> > > > Best regards,
> > > > Jingoo Han
> > > > 
> > > > >> Unable to handle kernel NULL pointer dereference at virtual
> > > > >> address 00000020 pgd = 80004000
> > > > >> [00000020] *pgd=00000000
> > > > >> Internal error: Oops: 17 [#1] SMP ARM
> > > > >> Modules linked in: sxdma(O)
> > > > >> CPU: 1 PID: 569 Comm: i2cipc.B3 Tainted: G           O
> > > > >> 3.12.0-next-20131105 #8 task: 9efcb600 ti: 9ec8c000 task.ti:
> > > > >> 9ec8c000 PC is at dw_msi_teardown_irq+0x40/0x118
> > > 
> > > see drivers/pci/host/pcie-designware.c :
> > > 
> > > 336 static void dw_msi_teardown_irq(struct msi_chip *chip, unsigned int
> > > irq) 337 {
> > > 338         clear_irq(irq);
> > > 339 }
> > > 
> > > So, add such a print before the clear_irq() call:
> > > 
> > > pr_err("%i %i\n", chip != NULL, irq);
> > > 
> > > And let us know the result please.
> > 
> > Here's what I get:
> > 
> > 1 391
> > 1 392
> 
> Also worth to mention is that I trigger this behavior by removing the
> device:
> 
> echo 1 > /sys/bus/pci/devices/0000:01:00.0/remove

Just for completeness, is this pure next or something else, like the 
boundarydevices's kernel ?

Best regards,
Marek Vasut