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From: Greg KH <gregkh@linuxfoundation.org>
To: Laurentiu Tudor <laurentiu.tudor@nxp.com>
Cc: heikki.krogerus@linux.intel.com, jon@solid-run.com,
	rafael.j.wysocki@intel.com, stable@vger.kernel.org
Subject: Re: [PATCH] software node: balance refcount for managed sw nodes
Date: Mon, 27 Sep 2021 14:17:32 +0200	[thread overview]
Message-ID: <YVG2XCK1nF4vVYP0@kroah.com> (raw)
In-Reply-To: <20210927102249.12939-1-laurentiu.tudor@nxp.com>

On Mon, Sep 27, 2021 at 01:22:49PM +0300, Laurentiu Tudor wrote:
> 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.
> 
> [Backported to stable from mainline commit
> 5aeb05b27f81 ("software node: balance refcount for managed software nodes")]
> 
> [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> # 5.12+
> ---
>  drivers/base/swnode.c | 3 +++
>  1 file changed, 3 insertions(+)

Next time, please include the git commit id of this patch that is
already in Linus's tree so that I don't have to go and manually look it
up...

thanks,

greg k-h

  reply	other threads:[~2021-09-27 12:17 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-27 10:22 [PATCH] software node: balance refcount for managed sw nodes Laurentiu Tudor
2021-09-27 12:17 ` Greg KH [this message]
2021-09-27 12:42   ` Laurentiu Tudor
2021-09-27 13:34     ` Greg KH
2021-09-27 13:36     ` Heikki Krogerus

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