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Subject: Re: [PATCH v2] xhci: solve a double free problem while doing s4
To:     "Zhangjiantao (Kirin, nanjing)" <water.zhangjiantao@huawei.com>,
        "gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>
Cc:     "mathias.nyman@intel.com" <mathias.nyman@intel.com>,
        "linux-usb@vger.kernel.org" <linux-usb@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "Xuetao (kirin)" <xuetao09@huawei.com>,
        "chenyu (U)" <chenyu56@huawei.com>,
        Caiyadong <caiyadong@huawei.com>,
        xuhaiyang <xuhaiyang5@hisilicon.com>
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From:   Mathias Nyman <mathias.nyman@linux.intel.com>
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Message-ID: <dd66b8ce-3d81-fc10-99e9-b2ef765f2dc9@linux.intel.com>
Date:   Mon, 14 Jun 2021 13:21:39 +0300
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In-Reply-To: <42e90d95-0544-cb46-a066-85d0cea0be48@huawei.com>
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Precedence: bulk

On 13.6.2021 15.08, Zhangjiantao (Kirin, nanjing) wrote:
> 
> On 2021/6/11 21:13, gregkh@linuxfoundation.org wrote :
>> On Fri, Jun 11, 2021 at 11:08:30AM +0000, Zhangjiantao (Kirin, nanjing) wrote:
>>> when system is doing s4, the process of xhci_resume may be as below:
>>> 1、xhci_mem_cleanup
>>> 2、xhci_init->xhci_mem_init->xhci_mem_cleanup(when memory is not enough).
>>> xhci_mem_cleanup will be executed twice when system is out of memory.
>>> xhci->port_caps is freed in xhci_mem_cleanup,but it isn't set to NULL.
>>> It will be freed twice when xhci_mem_cleanup is called the second time.
>>>
>>> We got following bug when system resumes from s4:
>>>
>>> kernel BUG at mm/slub.c:309!
>>> Internal error: Oops - BUG: 0 [#1] PREEMPT SMP
>>> CPU: 0 PID: 5929 Tainted: G S   W   5.4.96-arm64-desktop #1
>>> pc : __slab_free+0x5c/0x424
>>> lr : kfree+0x30c/0x32c
>>>
>>> Call trace:
>>>   __slab_free+0x5c/0x424
>>>   kfree+0x30c/0x32c
>>>   xhci_mem_cleanup+0x394/0x3cc
>>>   xhci_mem_init+0x9ac/0x1070
>>>   xhci_init+0x8c/0x1d0
>>>   xhci_resume+0x1cc/0x5fc
>>>   xhci_plat_resume+0x64/0x70
>>>   platform_pm_thaw+0x28/0x60
>>>   dpm_run_callback+0x54/0x24c
>>>   device_resume+0xd0/0x200
>>>   async_resume+0x24/0x60
>>>   async_run_entry_fn+0x44/0x110
>>>   process_one_work+0x1f0/0x490
>>>   worker_thread+0x5c/0x450
>>>   kthread+0x158/0x160
>>>   ret_from_fork+0x10/0x24
>>>
>>> Signed-off-by: Jiantao Zhang <water.zhangjiantao@huawei.com>
>>> Signed-off-by: Tao Xue <xuetao09@huawei.com>
>>> ---
>>>   drivers/usb/host/xhci-mem.c | 1 +
>>>   1 file changed, 1 insertion(+)
>>>
>>> diff --git a/drivers/usb/host/xhci-mem.c b/drivers/usb/host/xhci-mem.c index f66815f..e4b0c04 100644
>>> --- a/drivers/usb/host/xhci-mem.c
>>> +++ b/drivers/usb/host/xhci-mem.c
>>> @@ -1924,6 +1924,7 @@ void xhci_mem_cleanup(struct xhci_hcd *xhci)
>>>       xhci->hw_ports = NULL;
>>>       xhci->rh_bw = NULL;
>>>       xhci->ext_caps = NULL;
>>> +    xhci->port_caps = NULL;
>>>         xhci->page_size = 0;
>>>       xhci->page_shift = 0;
>>> -- 
>>> 2.7.4
>>>
>>
>> Hi,
>>
>> This is the friendly patch-bot of Greg Kroah-Hartman.  You have sent him
>> a patch that has triggered this response.  He used to manually respond
>> to these common problems, but in order to save his sanity (he kept
>> writing the same thing over and over, yet to different people), I was
>> created.  Hopefully you will not take offence and will fix the problem
>> in your patch and resubmit it so that it can be accepted into the Linux
>> kernel tree.
>>
>> You are receiving this message because of the following common error(s)
>> as indicated below:
>>
>> - This looks like a new version of a previously submitted patch, but you
>>    did not list below the --- line any changes from the previous version.
>>    Please read the section entitled "The canonical patch format" in the
>>    kernel file, Documentation/SubmittingPatches for what needs to be done
>>    here to properly describe this.
>>
>> If you wish to discuss this problem further, or you have questions about
>> how to resolve this issue, please feel free to respond to this email and
>> Greg will reply once he has dug out from the pending patches received
>> from other developers.
>>
>> thanks,
>>
>> greg k-h's patch email bot
> 
> Yes,there is no change of code line. I only added
> "Signed-off-by: Jiantao Zhang <water.zhangjiantao@huawei.com>" in the comments.
> thanks，
>    Jiantao Zhang
> 

I'll pick this up, add stable and fixes tags and send it forward.

Thanks
-Mathias