* [PATCH] ARM: OMAP2+: Grab reference to device nodes where needed
@ 2017-02-11 22:59 Guenter Roeck
2017-02-27 23:34 ` Guenter Roeck
0 siblings, 1 reply; 5+ messages in thread
From: Guenter Roeck @ 2017-02-11 22:59 UTC (permalink / raw)
To: Paul Walmsley
Cc: Tony Lindgren, Russell King, linux-omap, linux-arm-kernel,
linux-kernel, Guenter Roeck, Qi Hou, Peter Rosin, Rob Herring
After commit 'of: fix of_node leak caused in of_find_node_opts_by_path',
the following error may be reported when running omap images.
OF: ERROR: Bad of_node_put() on /ocp@68000000
CPU: 0 PID: 0 Comm: swapper Not tainted 4.10.0-rc7-next-20170210 #1
Hardware name: Generic OMAP3-GP (Flattened Device Tree)
[<c0310604>] (unwind_backtrace) from [<c030bbf4>] (show_stack+0x10/0x14)
[<c030bbf4>] (show_stack) from [<c05add8c>] (dump_stack+0x98/0xac)
[<c05add8c>] (dump_stack) from [<c05af1b0>] (kobject_release+0x48/0x7c)
[<c05af1b0>] (kobject_release)
from [<c0ad1aa4>] (of_find_node_by_name+0x74/0x94)
[<c0ad1aa4>] (of_find_node_by_name)
from [<c1215bd4>] (omap3xxx_hwmod_is_hs_ip_block_usable+0x24/0x2c)
[<c1215bd4>] (omap3xxx_hwmod_is_hs_ip_block_usable) from
[<c1215d5c>] (omap3xxx_hwmod_init+0x180/0x274)
[<c1215d5c>] (omap3xxx_hwmod_init)
from [<c120faa8>] (omap3_init_early+0xa0/0x11c)
[<c120faa8>] (omap3_init_early)
from [<c120fb2c>] (omap3430_init_early+0x8/0x30)
[<c120fb2c>] (omap3430_init_early)
from [<c1204710>] (setup_arch+0xc04/0xc34)
[<c1204710>] (setup_arch) from [<c1200948>] (start_kernel+0x68/0x38c)
[<c1200948>] (start_kernel) from [<8020807c>] (0x8020807c)
of_find_node_by_name() drops the reference to the passed device node,
so it is necessary to grab an extra one if it is still needed after the
call.
Cc: Qi Hou <qi.hou@windriver.com>
Cc: Peter Rosin <peda@axentia.se>
Cc: Rob Herring <robh@kernel.org>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
arch/arm/mach-omap2/omap_hwmod_3xxx_data.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/arch/arm/mach-omap2/omap_hwmod_3xxx_data.c b/arch/arm/mach-omap2/omap_hwmod_3xxx_data.c
index 56f917ec8621..d4ca1e3964c3 100644
--- a/arch/arm/mach-omap2/omap_hwmod_3xxx_data.c
+++ b/arch/arm/mach-omap2/omap_hwmod_3xxx_data.c
@@ -3117,6 +3117,7 @@ static int __init omap3xxx_hwmod_is_hs_ip_block_usable(struct device_node *bus,
if (!bus)
return (omap_type() == OMAP2_DEVICE_TYPE_GP) ? 1 : 0;
+ of_node_get(bus);
if (of_device_is_available(of_find_node_by_name(bus, dev_name)))
return 1;
@@ -3189,15 +3190,20 @@ int __init omap3xxx_hwmod_init(void)
if (h_sham && omap3xxx_hwmod_is_hs_ip_block_usable(bus, "sham")) {
r = omap_hwmod_register_links(h_sham);
- if (r < 0)
+ if (r < 0) {
+ of_node_put(bus);
return r;
+ }
}
if (h_aes && omap3xxx_hwmod_is_hs_ip_block_usable(bus, "aes")) {
r = omap_hwmod_register_links(h_aes);
- if (r < 0)
+ if (r < 0) {
+ of_node_put(bus);
return r;
+ }
}
+ of_node_put(bus);
/*
* Register hwmod links specific to certain ES levels of a
--
2.7.4
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: ARM: OMAP2+: Grab reference to device nodes where needed
2017-02-11 22:59 [PATCH] ARM: OMAP2+: Grab reference to device nodes where needed Guenter Roeck
@ 2017-02-27 23:34 ` Guenter Roeck
2017-02-28 16:23 ` Tony Lindgren
0 siblings, 1 reply; 5+ messages in thread
From: Guenter Roeck @ 2017-02-27 23:34 UTC (permalink / raw)
To: Paul Walmsley
Cc: Tony Lindgren, Russell King, linux-omap, linux-arm-kernel,
linux-kernel, Qi Hou, Peter Rosin, Rob Herring
ping ... this problem is now seen in mainline.
Guenter
On Sat, Feb 11, 2017 at 02:59:08PM -0800, Guenter Roeck wrote:
> After commit 'of: fix of_node leak caused in of_find_node_opts_by_path',
> the following error may be reported when running omap images.
>
> OF: ERROR: Bad of_node_put() on /ocp@68000000
> CPU: 0 PID: 0 Comm: swapper Not tainted 4.10.0-rc7-next-20170210 #1
> Hardware name: Generic OMAP3-GP (Flattened Device Tree)
> [<c0310604>] (unwind_backtrace) from [<c030bbf4>] (show_stack+0x10/0x14)
> [<c030bbf4>] (show_stack) from [<c05add8c>] (dump_stack+0x98/0xac)
> [<c05add8c>] (dump_stack) from [<c05af1b0>] (kobject_release+0x48/0x7c)
> [<c05af1b0>] (kobject_release)
> from [<c0ad1aa4>] (of_find_node_by_name+0x74/0x94)
> [<c0ad1aa4>] (of_find_node_by_name)
> from [<c1215bd4>] (omap3xxx_hwmod_is_hs_ip_block_usable+0x24/0x2c)
> [<c1215bd4>] (omap3xxx_hwmod_is_hs_ip_block_usable) from
> [<c1215d5c>] (omap3xxx_hwmod_init+0x180/0x274)
> [<c1215d5c>] (omap3xxx_hwmod_init)
> from [<c120faa8>] (omap3_init_early+0xa0/0x11c)
> [<c120faa8>] (omap3_init_early)
> from [<c120fb2c>] (omap3430_init_early+0x8/0x30)
> [<c120fb2c>] (omap3430_init_early)
> from [<c1204710>] (setup_arch+0xc04/0xc34)
> [<c1204710>] (setup_arch) from [<c1200948>] (start_kernel+0x68/0x38c)
> [<c1200948>] (start_kernel) from [<8020807c>] (0x8020807c)
>
> of_find_node_by_name() drops the reference to the passed device node,
> so it is necessary to grab an extra one if it is still needed after the
> call.
>
> Cc: Qi Hou <qi.hou@windriver.com>
> Cc: Peter Rosin <peda@axentia.se>
> Cc: Rob Herring <robh@kernel.org>
> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
> ---
> arch/arm/mach-omap2/omap_hwmod_3xxx_data.c | 10 ++++++++--
> 1 file changed, 8 insertions(+), 2 deletions(-)
>
> diff --git a/arch/arm/mach-omap2/omap_hwmod_3xxx_data.c b/arch/arm/mach-omap2/omap_hwmod_3xxx_data.c
> index 56f917ec8621..d4ca1e3964c3 100644
> --- a/arch/arm/mach-omap2/omap_hwmod_3xxx_data.c
> +++ b/arch/arm/mach-omap2/omap_hwmod_3xxx_data.c
> @@ -3117,6 +3117,7 @@ static int __init omap3xxx_hwmod_is_hs_ip_block_usable(struct device_node *bus,
> if (!bus)
> return (omap_type() == OMAP2_DEVICE_TYPE_GP) ? 1 : 0;
>
> + of_node_get(bus);
> if (of_device_is_available(of_find_node_by_name(bus, dev_name)))
> return 1;
>
> @@ -3189,15 +3190,20 @@ int __init omap3xxx_hwmod_init(void)
>
> if (h_sham && omap3xxx_hwmod_is_hs_ip_block_usable(bus, "sham")) {
> r = omap_hwmod_register_links(h_sham);
> - if (r < 0)
> + if (r < 0) {
> + of_node_put(bus);
> return r;
> + }
> }
>
> if (h_aes && omap3xxx_hwmod_is_hs_ip_block_usable(bus, "aes")) {
> r = omap_hwmod_register_links(h_aes);
> - if (r < 0)
> + if (r < 0) {
> + of_node_put(bus);
> return r;
> + }
> }
> + of_node_put(bus);
>
> /*
> * Register hwmod links specific to certain ES levels of a
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: ARM: OMAP2+: Grab reference to device nodes where needed
2017-02-27 23:34 ` Guenter Roeck
@ 2017-02-28 16:23 ` Tony Lindgren
2017-02-28 17:26 ` Guenter Roeck
0 siblings, 1 reply; 5+ messages in thread
From: Tony Lindgren @ 2017-02-28 16:23 UTC (permalink / raw)
To: Guenter Roeck
Cc: Paul Walmsley, Rob Herring, Russell King, linux-kernel, Qi Hou,
linux-omap, Peter Rosin, linux-arm-kernel
* Guenter Roeck <linux@roeck-us.net> [170227 15:36]:
> ping ... this problem is now seen in mainline.
Oops sorry I had accidentally tagged this with "next" instead of
"fixes".
Looking at the patch though, can't we make of_node_get/put local to
omap3xxx_hwmod_is_hs_ip_block_usable()?
Regards,
Tony
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: ARM: OMAP2+: Grab reference to device nodes where needed
2017-02-28 16:23 ` Tony Lindgren
@ 2017-02-28 17:26 ` Guenter Roeck
2017-02-28 17:52 ` Tony Lindgren
0 siblings, 1 reply; 5+ messages in thread
From: Guenter Roeck @ 2017-02-28 17:26 UTC (permalink / raw)
To: Tony Lindgren
Cc: Paul Walmsley, Rob Herring, Russell King, linux-kernel, Qi Hou,
linux-omap, Peter Rosin, linux-arm-kernel
On Tue, Feb 28, 2017 at 08:23:16AM -0800, Tony Lindgren wrote:
> * Guenter Roeck <linux@roeck-us.net> [170227 15:36]:
> > ping ... this problem is now seen in mainline.
>
> Oops sorry I had accidentally tagged this with "next" instead of
> "fixes".
>
> Looking at the patch though, can't we make of_node_get/put local to
> omap3xxx_hwmod_is_hs_ip_block_usable()?
>
Not really.
Strictly speaking the patch fixes two problems:
1) of_find_node_by_name() gets a reference on "bus", thus of_node_put()
is necessary to release it. This is the change in omap3xxx_hwmod_init().
2) of_find_node_by_name() drops a reference to the passed device node,
thus it is necessary to call of_node_get(bus) in
omap3xxx_hwmod_is_hs_ip_block_usable().
I should have stated that more clearly in the description.
We could ignore 1) to get rid of the warning, but that would leave us with
a dangling reference to the bus node. I could also improve the description,
or split the patch in two. Let me know what you prefer.
Another possible change would be to use of_get_child_by_name() instead of
of_find_node_by_name(). That would, however, only search immediate children
of the 'ocp' node, not all nodes. I think that is what is actually intended
here, but I am not entirely sure. Thoughts ?
Either case, turns out I'll have to re-submit the patch because, as mentioned
above, of_find_node_by_name() gets a reference to the device node it returns,
so a put on that node is necessary in omap3xxx_hwmod_is_hs_ip_block_usable().
Guenter
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: ARM: OMAP2+: Grab reference to device nodes where needed
2017-02-28 17:26 ` Guenter Roeck
@ 2017-02-28 17:52 ` Tony Lindgren
0 siblings, 0 replies; 5+ messages in thread
From: Tony Lindgren @ 2017-02-28 17:52 UTC (permalink / raw)
To: Guenter Roeck
Cc: Paul Walmsley, Rob Herring, Russell King, linux-kernel, Qi Hou,
linux-omap, Peter Rosin, linux-arm-kernel
* Guenter Roeck <linux@roeck-us.net> [170228 09:28]:
> On Tue, Feb 28, 2017 at 08:23:16AM -0800, Tony Lindgren wrote:
> > * Guenter Roeck <linux@roeck-us.net> [170227 15:36]:
> > > ping ... this problem is now seen in mainline.
> >
> > Oops sorry I had accidentally tagged this with "next" instead of
> > "fixes".
> >
> > Looking at the patch though, can't we make of_node_get/put local to
> > omap3xxx_hwmod_is_hs_ip_block_usable()?
> >
> Not really.
>
> Strictly speaking the patch fixes two problems:
> 1) of_find_node_by_name() gets a reference on "bus", thus of_node_put()
> is necessary to release it. This is the change in omap3xxx_hwmod_init().
> 2) of_find_node_by_name() drops a reference to the passed device node,
> thus it is necessary to call of_node_get(bus) in
> omap3xxx_hwmod_is_hs_ip_block_usable().
>
> I should have stated that more clearly in the description.
OK
> We could ignore 1) to get rid of the warning, but that would leave us with
> a dangling reference to the bus node. I could also improve the description,
> or split the patch in two. Let me know what you prefer.
Once patch is just fine with me.
> Another possible change would be to use of_get_child_by_name() instead of
> of_find_node_by_name(). That would, however, only search immediate children
> of the 'ocp' node, not all nodes. I think that is what is actually intended
> here, but I am not entirely sure. Thoughts ?
Yes that would be better.
> Either case, turns out I'll have to re-submit the patch because, as mentioned
> above, of_find_node_by_name() gets a reference to the device node it returns,
> so a put on that node is necessary in omap3xxx_hwmod_is_hs_ip_block_usable().
OK
Thanks,
Tony
^ permalink raw reply [flat|nested] 5+ messages in thread
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2017-02-11 22:59 [PATCH] ARM: OMAP2+: Grab reference to device nodes where needed Guenter Roeck
2017-02-27 23:34 ` Guenter Roeck
2017-02-28 16:23 ` Tony Lindgren
2017-02-28 17:26 ` Guenter Roeck
2017-02-28 17:52 ` Tony Lindgren
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