linux-kernel - Re: [PATCH] of: Don't allow __of_attached_node_sysfs() without CONFIG

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Message-ID: <YSPtmp1eyQdSKITz@robh.at.kernel.org>
Date:   Mon, 23 Aug 2021 13:48:58 -0500
From:   Rob Herring <robh@...nel.org>
To:     Marc Zyngier <maz@...nel.org>
Cc:     linux-kernel@...r.kernel.org, devicetree@...r.kernel.org,
        frowand.list@...il.com, robh+dt@...nel.org, kernel-team@...roid.com
Subject: Re: [PATCH] of: Don't allow __of_attached_node_sysfs() without
 CONFIG_SYSFS

On Fri, 20 Aug 2021 15:47:22 +0100, Marc Zyngier wrote:
> Trying to boot without SYSFS, but with OF_DYNAMIC quickly
> results in a crash:
> 
> [    0.088460] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000070
> [...]
> [    0.103927] CPU: 1 PID: 1 Comm: swapper/0 Not tainted 5.14.0-rc3 #4179
> [    0.105810] Hardware name: linux,dummy-virt (DT)
> [    0.107147] pstate: 80000005 (Nzcv daif -PAN -UAO -TCO BTYPE=--)
> [    0.108876] pc : kernfs_find_and_get_ns+0x3c/0x7c
> [    0.110244] lr : kernfs_find_and_get_ns+0x3c/0x7c
> [...]
> [    0.134087] Call trace:
> [    0.134800]  kernfs_find_and_get_ns+0x3c/0x7c
> [    0.136054]  safe_name+0x4c/0xd0
> [    0.136994]  __of_attach_node_sysfs+0xf8/0x124
> [    0.138287]  of_core_init+0x90/0xfc
> [    0.139296]  driver_init+0x30/0x4c
> [    0.140283]  kernel_init_freeable+0x160/0x1b8
> [    0.141543]  kernel_init+0x30/0x140
> [    0.142561]  ret_from_fork+0x10/0x18
> 
> While not having sysfs isn't a very common option these days,
> it is still expected that such configuration would work.
> 
> Paper over it by bailing out from __of_attach_node_sysfs() if
> CONFIG_SYSFS isn't enabled.
> 
> Signed-off-by: Marc Zyngier <maz@...nel.org>
> ---
>  drivers/of/kobj.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 

Applied, thanks!