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* [PATCH v3] software node: balance refcount for managed sw nodes
@ 2021-09-15  8:09 laurentiu.tudor
  2021-09-15 12:02 ` Rafael J. Wysocki
  0 siblings, 1 reply; 2+ messages in thread
From: laurentiu.tudor @ 2021-09-15  8:09 UTC (permalink / raw)
  To: andriy.shevchenko, heikki.krogerus, gregkh, rafael, linux-acpi,
	linux-kernel
  Cc: jon, Laurentiu Tudor, stable

From: Laurentiu Tudor <laurentiu.tudor@nxp.com>

software_node_notify(), on KOBJ_REMOVE drops the refcount twice on managed
software nodes, thus leading to underflow errors. Balance the refcount by
bumping it in the device_create_managed_software_node() function.

The error [1] was encountered after adding a .shutdown() op to our
fsl-mc-bus driver.

[1]
pc : refcount_warn_saturate+0xf8/0x150
lr : refcount_warn_saturate+0xf8/0x150
sp : ffff80001009b920
x29: ffff80001009b920 x28: ffff1a2420318000 x27: 0000000000000000
x26: ffffccac15e7a038 x25: 0000000000000008 x24: ffffccac168e0030
x23: ffff1a2428a82000 x22: 0000000000080000 x21: ffff1a24287b5000
x20: 0000000000000001 x19: ffff1a24261f4400 x18: ffffffffffffffff
x17: 6f72645f726f7272 x16: 0000000000000000 x15: ffff80009009b607
x14: 0000000000000000 x13: ffffccac16602670 x12: 0000000000000a17
x11: 000000000000035d x10: ffffccac16602670 x9 : ffffccac16602670
x8 : 00000000ffffefff x7 : ffffccac1665a670 x6 : ffffccac1665a670
x5 : 0000000000000000 x4 : 0000000000000000 x3 : 00000000ffffffff
x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff1a2420318000
Call trace:
 refcount_warn_saturate+0xf8/0x150
 kobject_put+0x10c/0x120
 software_node_notify+0xd8/0x140
 device_platform_notify+0x4c/0xb4
 device_del+0x188/0x424
 fsl_mc_device_remove+0x2c/0x4c
 rebofind sp.c__fsl_mc_device_remove+0x14/0x2c
 device_for_each_child+0x5c/0xac
 dprc_remove+0x9c/0xc0
 fsl_mc_driver_remove+0x28/0x64
 __device_release_driver+0x188/0x22c
 device_release_driver+0x30/0x50
 bus_remove_device+0x128/0x134
 device_del+0x16c/0x424
 fsl_mc_bus_remove+0x8c/0x114
 fsl_mc_bus_shutdown+0x14/0x20
 platform_shutdown+0x28/0x40
 device_shutdown+0x15c/0x330
 __do_sys_reboot+0x218/0x2a0
 __arm64_sys_reboot+0x28/0x34
 invoke_syscall+0x48/0x114
 el0_svc_common+0x40/0xdc
 do_el0_svc+0x2c/0x94
 el0_svc+0x2c/0x54
 el0t_64_sync_handler+0xa8/0x12c
 el0t_64_sync+0x198/0x19c
---[ end trace 32eb1c71c7d86821 ]---

Fixes: 151f6ff78cdf ("software node: Provide replacement for device_add_properties()")
Reported-by: Jon Nettleton <jon@solid-run.com>
Suggested-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Laurentiu Tudor <laurentiu.tudor@nxp.com>
Cc: stable@vger.kernel.org
---
Changes since v2:
 - added Fixes: tag
 - Cc-ed stable

Changes since v1:
 - added Heikki's Reviewed-by: (Thanks!)

Changes since RFC:
 - use software_node_notify(KOBJ_ADD) instead of directly bumping
   refcount (Heikki)


 drivers/base/swnode.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/base/swnode.c b/drivers/base/swnode.c
index d1f1a8240120..bdb50a06c82a 100644
--- a/drivers/base/swnode.c
+++ b/drivers/base/swnode.c
@@ -1113,6 +1113,9 @@ int device_create_managed_software_node(struct device *dev,
 	to_swnode(fwnode)->managed = true;
 	set_secondary_fwnode(dev, fwnode);
 
+	if (device_is_registered(dev))
+		software_node_notify(dev, KOBJ_ADD);
+
 	return 0;
 }
 EXPORT_SYMBOL_GPL(device_create_managed_software_node);
-- 
2.17.1


^ permalink raw reply related	[flat|nested] 2+ messages in thread
* Re: [PATCH v3] software node: balance refcount for managed sw nodes
  2021-09-15  8:09 [PATCH v3] software node: balance refcount for managed sw nodes laurentiu.tudor
@ 2021-09-15 12:02 ` Rafael J. Wysocki
  0 siblings, 0 replies; 2+ messages in thread
From: Rafael J. Wysocki @ 2021-09-15 12:02 UTC (permalink / raw)
  To: Laurentiu Tudor
  Cc: Andy Shevchenko, Heikki Krogerus, Greg Kroah-Hartman,
	Rafael J. Wysocki, ACPI Devel Maling List,
	Linux Kernel Mailing List, Jon, Stable

On Wed, Sep 15, 2021 at 10:10 AM <laurentiu.tudor@nxp.com> wrote:
>
> From: Laurentiu Tudor <laurentiu.tudor@nxp.com>
>
> software_node_notify(), on KOBJ_REMOVE drops the refcount twice on managed
> software nodes, thus leading to underflow errors. Balance the refcount by
> bumping it in the device_create_managed_software_node() function.
>
> The error [1] was encountered after adding a .shutdown() op to our
> fsl-mc-bus driver.
>
> [1]
> pc : refcount_warn_saturate+0xf8/0x150
> lr : refcount_warn_saturate+0xf8/0x150
> sp : ffff80001009b920
> x29: ffff80001009b920 x28: ffff1a2420318000 x27: 0000000000000000
> x26: ffffccac15e7a038 x25: 0000000000000008 x24: ffffccac168e0030
> x23: ffff1a2428a82000 x22: 0000000000080000 x21: ffff1a24287b5000
> x20: 0000000000000001 x19: ffff1a24261f4400 x18: ffffffffffffffff
> x17: 6f72645f726f7272 x16: 0000000000000000 x15: ffff80009009b607
> x14: 0000000000000000 x13: ffffccac16602670 x12: 0000000000000a17
> x11: 000000000000035d x10: ffffccac16602670 x9 : ffffccac16602670
> x8 : 00000000ffffefff x7 : ffffccac1665a670 x6 : ffffccac1665a670
> x5 : 0000000000000000 x4 : 0000000000000000 x3 : 00000000ffffffff
> x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff1a2420318000
> Call trace:
>  refcount_warn_saturate+0xf8/0x150
>  kobject_put+0x10c/0x120
>  software_node_notify+0xd8/0x140
>  device_platform_notify+0x4c/0xb4
>  device_del+0x188/0x424
>  fsl_mc_device_remove+0x2c/0x4c
>  rebofind sp.c__fsl_mc_device_remove+0x14/0x2c
>  device_for_each_child+0x5c/0xac
>  dprc_remove+0x9c/0xc0
>  fsl_mc_driver_remove+0x28/0x64
>  __device_release_driver+0x188/0x22c
>  device_release_driver+0x30/0x50
>  bus_remove_device+0x128/0x134
>  device_del+0x16c/0x424
>  fsl_mc_bus_remove+0x8c/0x114
>  fsl_mc_bus_shutdown+0x14/0x20
>  platform_shutdown+0x28/0x40
>  device_shutdown+0x15c/0x330
>  __do_sys_reboot+0x218/0x2a0
>  __arm64_sys_reboot+0x28/0x34
>  invoke_syscall+0x48/0x114
>  el0_svc_common+0x40/0xdc
>  do_el0_svc+0x2c/0x94
>  el0_svc+0x2c/0x54
>  el0t_64_sync_handler+0xa8/0x12c
>  el0t_64_sync+0x198/0x19c
> ---[ end trace 32eb1c71c7d86821 ]---
>
> Fixes: 151f6ff78cdf ("software node: Provide replacement for device_add_properties()")
> Reported-by: Jon Nettleton <jon@solid-run.com>
> Suggested-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
> Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
> Signed-off-by: Laurentiu Tudor <laurentiu.tudor@nxp.com>
> Cc: stable@vger.kernel.org
> ---
> Changes since v2:
>  - added Fixes: tag
>  - Cc-ed stable
>
> Changes since v1:
>  - added Heikki's Reviewed-by: (Thanks!)
>
> Changes since RFC:
>  - use software_node_notify(KOBJ_ADD) instead of directly bumping
>    refcount (Heikki)
>
>
>  drivers/base/swnode.c | 3 +++
>  1 file changed, 3 insertions(+)
>
> diff --git a/drivers/base/swnode.c b/drivers/base/swnode.c
> index d1f1a8240120..bdb50a06c82a 100644
> --- a/drivers/base/swnode.c
> +++ b/drivers/base/swnode.c
> @@ -1113,6 +1113,9 @@ int device_create_managed_software_node(struct device *dev,
>         to_swnode(fwnode)->managed = true;
>         set_secondary_fwnode(dev, fwnode);
>
> +       if (device_is_registered(dev))
> +               software_node_notify(dev, KOBJ_ADD);
> +
>         return 0;
>  }
>  EXPORT_SYMBOL_GPL(device_create_managed_software_node);
> --

Applied as 5.15-rc material, thanks!

^ permalink raw reply	[flat|nested] 2+ messages in thread
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2021-09-15  8:09 [PATCH v3] software node: balance refcount for managed sw nodes laurentiu.tudor
2021-09-15 12:02 ` Rafael J. Wysocki

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