linux-kernel - Re: [PATCH 11/33] arm_mpam: Add the class and component structures for firmware described ris

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

Message-ID: <47603a3c-e94d-4452-9f09-0e27ff02e18b@arm.com>
Date: Thu, 13 Nov 2025 16:39:48 +0000
From: Ben Horgan <ben.horgan@....com>
To: Fenghua Yu <fenghuay@...dia.com>, james.morse@....com
Cc: amitsinght@...vell.com, baisheng.gao@...soc.com,
 baolin.wang@...ux.alibaba.com, bobo.shaobowang@...wei.com,
 carl@...amperecomputing.com, catalin.marinas@....com, dakr@...nel.org,
 dave.martin@....com, david@...hat.com, dfustini@...libre.com,
 gregkh@...uxfoundation.org, gshan@...hat.com, guohanjun@...wei.com,
 jeremy.linton@....com, jonathan.cameron@...wei.com, kobak@...dia.com,
 lcherian@...vell.com, lenb@...nel.org, linux-acpi@...r.kernel.org,
 linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
 lpieralisi@...nel.org, peternewman@...gle.com, quic_jiles@...cinc.com,
 rafael@...nel.org, robh@...nel.org, rohit.mathew@....com,
 scott@...amperecomputing.com, sdonthineni@...dia.com, sudeep.holla@....com,
 tan.shaopeng@...itsu.com, will@...nel.org, xhao@...ux.alibaba.com,
 Shaopeng Tan <tan.shaopeng@...fujitsu.com>
Subject: Re: [PATCH 11/33] arm_mpam: Add the class and component structures
 for firmware described ris

Hi Fenghua,

On 11/13/25 03:23, Fenghua Yu wrote:
> Hi, Ben and James,
> 
> On 11/7/25 04:34, Ben Horgan wrote:
>> From: James Morse <james.morse@....com>
> 
> [SNIP]
> 
>> +static int mpam_ris_create_locked(struct mpam_msc *msc, u8 ris_idx,
>> +                  enum mpam_class_types type, u8 class_id,
>> +                  int component_id)
>> +{
>> +    int err;
>> +    struct mpam_vmsc *vmsc;
>> +    struct mpam_msc_ris *ris;
>> +    struct mpam_class *class;
>> +    struct mpam_component *comp;
>> +    struct platform_device *pdev = msc->pdev;
>> +
>> +    lockdep_assert_held(&mpam_list_lock);
>> +
>> +    if (ris_idx > MPAM_MSC_MAX_NUM_RIS)
>> +        return -EINVAL;
>> +
>> +    if (test_and_set_bit(ris_idx, &msc->ris_idxs))
>> +        return -EBUSY;
>> +
>> +    ris = devm_kzalloc(&msc->pdev->dev, sizeof(*ris), GFP_KERNEL);
>> +    if (!ris)
>> +        return -ENOMEM;
> 
> The ris_idx bit in msc->ris_idxs is not cleared on error paths in this
> function. The bit cannot be set again.
> 
> Not sure if this is a real problem in any case. Clearing the bit on
> error paths may be clean code.

I think this would just add noise. There is no anticipation of any
functionality after failing to create RIS and I expect there are more
places in the code where this assumption is relied on.

> 
> [SNIP]
> 
> Thanks.
> 
> -Fenghua

Thanks,

Ben