linux-kernel - Re: [PATCH v1 1/1] mfd: Remove software node conditionally and locate at right place

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Date:   Wed, 19 May 2021 13:03:02 +0100
From:   Lee Jones <lee.jones@...aro.org>
To:     Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Cc:     linux-kernel@...r.kernel.org,
        Heikki Krogerus <heikki.krogerus@...ux.intel.com>
Subject: Re: [PATCH v1 1/1] mfd: Remove software node conditionally and
 locate at right place

On Mon, 10 May 2021, Andy Shevchenko wrote:

> Currently the software node is removed in error case and at ->remove()
> stage unconditionally, that ruins the symmetry. Besides, in some cases,
> when mfd_add_device() fails, the device_remove_software_node() call
> may lead to NULL pointer dereference:
> 
>   BUG: kernel NULL pointer dereference, address: 00000000
>   ...
>   EIP: strlen+0x12/0x20
>   ...
>   kernfs_name_hash+0x13/0x70
>   kernfs_find_ns+0x32/0xc0
>   kernfs_remove_by_name_ns+0x2a/0x90
>   sysfs_remove_link+0x16/0x30
>   software_node_notify.cold+0x34/0x6b
>   device_remove_software_node+0x5a/0x90
>   mfd_add_device.cold+0x30a/0x427
> 
> Fix all these by guarding device_remove_software_node() with a conditional
> and locating it at the right place.
> 
> Fixes: 42e59982917a ("mfd: core: Add support for software nodes")
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
> ---
>  drivers/mfd/mfd-core.c | 15 +++++++++------
>  1 file changed, 9 insertions(+), 6 deletions(-)

Applied, thanks.

-- 
Lee Jones [李琼斯]
Senior Technical Lead - Developer Services
Linaro.org │ Open source software for Arm SoCs
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