linux-kernel - Re: [PATCH] memory: mtk-smi: Fix NULL pointer dereference in config

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <CAGmiHmGiDngNCkfkwdoV8M0XjQVFEXTJekPAfuZfUFRui9gSbg@mail.gmail.com>
Date: Fri, 14 Nov 2025 11:03:28 +0800
From: Jian Hui Lee <jianhui.lee@...onical.com>
To: Krzysztof Kozlowski <krzk@...nel.org>
Cc: Yong Wu <yong.wu@...iatek.com>, Matthias Brugger <matthias.bgg@...il.com>, 
	AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>, Joerg Roedel <jroedel@...e.de>, 
	linux-mediatek@...ts.infradead.org, linux-kernel@...r.kernel.org, 
	linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH] memory: mtk-smi: Fix NULL pointer dereference in config_port

On Wed, Nov 12, 2025 at 11:51 PM Krzysztof Kozlowski <krzk@...nel.org> wrote:
>
> Please trim the traces from all irrelevant information.
>
> >
> > Fixes: e6dec92308628 ("iommu/mediatek: Add mt2712 IOMMU support")
>
> Add Cc stable.
>
> > Signed-off-by: Jian Hui Lee <jianhui.lee@...onical.com>
>
> > ---
> >  drivers/memory/mtk-smi.c | 4 ++++
> >  1 file changed, 4 insertions(+)
> >
> > diff --git a/drivers/memory/mtk-smi.c b/drivers/memory/mtk-smi.c
> > index 733e22f695ab..8eb043ff8280 100644
> > --- a/drivers/memory/mtk-smi.c
> > +++ b/drivers/memory/mtk-smi.c
> > @@ -244,6 +244,10 @@ static int mtk_smi_larb_config_port_gen2_general(struct device *dev)
> >       struct arm_smccc_res res;
> >       int i;
> >
> > +     /* larb->mmu and larb->bank are set in bind(), may not be ready yet */
>
> And how do you synchronize this between CPUs? IOW, what certainty you
> have that this CPU sees correct data and the checks below have any sense?

Thank you for the review and for pointing this out. Moving
pm_runtime_enable/disable to component bind/unbind should ensure that
the synchronization happens correctly. I will send a v2 to address
those you mentioned.

> > +     if (!larb->mmu || !larb->bank)
> > +             return 0;
> > +
> >       if (BIT(larb->larbid) & larb->larb_gen->larb_direct_to_common_mask)
> >               return 0;
> >
>
> Best regards,
> Krzysztof