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Message-ID: <1388375977.4373.26.camel@pasglop>
Date: Mon, 30 Dec 2013 14:59:37 +1100
From: Benjamin Herrenschmidt <benh@...nel.crashing.org>
To: Rob Herring <robherring2@...il.com>
Cc: Cédric Le Goater <clg@...ibm.com>,
Grant Likely <grant.likely@...aro.org>,
"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
linuxppc-dev <linuxppc-dev@...ts.ozlabs.org>,
Thierry Reding <thierry.reding@...il.com>,
Linux Kernel list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] of/irq: Fix device_node refcount in of_irq_parse_raw()
On Sun, 2013-12-29 at 20:42 -0600, Rob Herring wrote:
> On Sun, Dec 29, 2013 at 8:37 PM, Benjamin Herrenschmidt
> <benh@...nel.crashing.org> wrote:
>
> On Tue, 2013-12-17 at 18:32 +0100, Cédric Le Goater wrote:
> > Commit 2361613206e6, "of/irq: Refactor interrupt-map
> parsing" changed
> > the refcount on the device_node causing an error in
> of_node_put():
>
>
> Grant, Thierry, this is a regression, please send to Linus
> ASAP...
>
>
>
> I'm working on doing that right this moment.
Thanks, looks like I'm not the only trying to get some work done
today :)
Cheers,
Ben.
>
> Rob
>
> Cheers,
> Ben.
>
> > ERROR: Bad of_node_put() on /pci@...000020000000
> > CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.13.0-rc3-dirty
> #2
> > Call Trace:
> > [c00000003e403500] [c0000000000144fc] .show_stack+0x7c/0x1f0
> (unreliable)
> > [c00000003e4035d0] [c00000000070f250] .dump_stack+0x88/0xb4
> > [c00000003e403650] [c0000000005e8768] .of_node_release
> +0xd8/0xf0
> > [c00000003e4036e0] [c0000000005eeafc] .of_irq_parse_one
> +0x10c/0x280
> > [c00000003e4037a0] [c0000000005efd4c] .of_irq_parse_pci
> +0x3c/0x1d0
> > [c00000003e403840] [c000000000038240] .pcibios_setup_device
> +0xa0/0x2e0
> > [c00000003e403910]
> [c0000000000398f0] .pcibios_setup_bus_devices+0x60/0xd0
> > [c00000003e403990] [c00000000003b3a4] .__of_scan_bus
> +0x1a4/0x2b0
> > [c00000003e403a80] [c00000000003a62c] .pcibios_scan_phb
> +0x30c/0x410
> > [c00000003e403b60] [c0000000009fe430] .pcibios_init
> +0x7c/0xd4
> >
> > This patch adjusts the refcount in the walk of the interrupt
> tree.
> > When a match is found, there is no need to increase the
> refcount
> > on 'out_irq->np' as 'newpar' is already holding a ref. The
> refcount
> > balance between 'ipar' and 'newpar' is maintained in the
> skiplevel:
> > goto label.
> >
> > This patch also removes the usage of the device_node
> variable 'old'
> > which seems useless after the latest changes.
> >
> > Signed-off-by: Cédric Le Goater <clg@...ibm.com>
> > ---
> >
> > This patch was tested on powerpc, pseries and powernv. This
> is a
> > new area for me so I might have missed a path. Please take a
> look.
> >
> > We could now introduce an helper routine to look for
> #address-cells in
> > of_irq_parse_raw(). This can be the subject of another
> patch.
> >
> > Thanks,
> >
> > C.
> >
> > drivers/of/irq.c | 5 +----
> > 1 file changed, 1 insertion(+), 4 deletions(-)
> >
> > diff --git a/drivers/of/irq.c b/drivers/of/irq.c
> > index 786b0b47fae4..27212402c532 100644
> > --- a/drivers/of/irq.c
> > +++ b/drivers/of/irq.c
> > @@ -165,7 +165,6 @@ int of_irq_parse_raw(const __be32 *addr,
> struct of_phandle_args *out_irq)
> > if (of_get_property(ipar,
> "interrupt-controller", NULL) !=
> > NULL) {
> > pr_debug(" -> got it !\n");
> > - of_node_put(old);
> > return 0;
> > }
> >
> > @@ -250,8 +249,7 @@ int of_irq_parse_raw(const __be32 *addr,
> struct of_phandle_args *out_irq)
> > * Successfully parsed an interrrupt-map
> translation; copy new
> > * interrupt specifier into the out_irq
> structure
> > */
> > - of_node_put(out_irq->np);
> > - out_irq->np = of_node_get(newpar);
> > + out_irq->np = newpar;
> >
> > match_array = imap - newaddrsize - newintsize;
> > for (i = 0; i < newintsize; i++)
> > @@ -268,7 +266,6 @@ int of_irq_parse_raw(const __be32 *addr,
> struct of_phandle_args *out_irq)
> > }
> > fail:
> > of_node_put(ipar);
> > - of_node_put(out_irq->np);
> > of_node_put(newpar);
> >
> > return -EINVAL;
>
>
> --
>
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