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Message-ID: <4a0ada8a-5247-4c1c-b938-a6ae034b04d9@samsung.com>
Date: Wed, 21 Aug 2024 10:59:21 +0530
From: Selvarasu Ganesan <selvarasu.g@...sung.com>
To: Greg KH <gregkh@...uxfoundation.org>
Cc: Thinh.Nguyen@...opsys.com, linux-usb@...r.kernel.org,
linux-kernel@...r.kernel.org, jh0801.jung@...sung.com,
dh10.jung@...sung.com, naushad@...sung.com, akash.m5@...sung.com,
rc93.raju@...sung.com, taehyun.cho@...sung.com, hongpooh.kim@...sung.com,
eomji.oh@...sung.com, shijie.cai@...sung.com, stable@...r.kernel.org
Subject: Re: [PATCH v3] usb: dwc3: core: Prevent USB core invalid event
buffer address access
On 8/17/2024 7:13 PM, Selvarasu Ganesan wrote:
> On 8/17/2024 10:47 AM, Greg KH wrote:
>> On Fri, Aug 16, 2024 at 09:13:09PM +0530, Selvarasu Ganesan wrote:
>>> On 8/16/2024 3:25 PM, Greg KH wrote:
>>>> On Thu, Aug 15, 2024 at 12:18:31PM +0530, Selvarasu Ganesan wrote:
>>>>> This commit addresses an issue where the USB core could access an
>>>>> invalid event buffer address during runtime suspend, potentially causing
>>>>> SMMU faults and other memory issues in Exynos platforms. The problem
>>>>> arises from the following sequence.
>>>>> 1. In dwc3_gadget_suspend, there is a chance of a timeout when
>>>>> moving the USB core to the halt state after clearing the
>>>>> run/stop bit by software.
>>>>> 2. In dwc3_core_exit, the event buffer is cleared regardless of
>>>>> the USB core's status, which may lead to an SMMU faults and
>>>>> other memory issues. if the USB core tries to access the event
>>>>> buffer address.
>>>>>
>>>>> To prevent this hardware quirk on Exynos platforms, this commit ensures
>>>>> that the event buffer address is not cleared by software when the USB
>>>>> core is active during runtime suspend by checking its status before
>>>>> clearing the buffer address.
>>>>>
>>>>> Cc: stable@...r.kernel.org # v6.1+
>>>> Any hint as to what commit id this fixes?
>>>>
>>>> thanks,
>>>>
>>>> greg k-h
>>> Hi Greg,
>>>
>>> This issue is not related to any particular commit. The given fix is
>>> address a hardware quirk on the Exynos platform. And we require it to be
>>> backported on stable kernel 6.1 and above all stable kernel.
>> If it's a hardware quirk issue, why are you restricting it to a specific
>> kernel release and not a specific kernel commit? Why not 5.15? 5.4?
> Hi Greg,
>
> I mentioned a specific kernel because our platform is set to be tested
> and functioning with kernels 6.1 and above, and the issue was reported
> with these kernel versions. However, we would be fine if all stable
> kernels, such as 5.4 and 5.15, were backported. In this case, if you
> need a new patch version to update the Cc tag for all stable kernels,
> please suggest the Cc tag to avoid confusion in next version.
>
> Thanks,
> Selva
Hi Greg,
Would you like to provide any feedback or suggestions regarding the my
last comments mentioned above?
Thanks,
Selva
>> thanks,
>>
>> greg k-h
>>
>>
>
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