Re: [PATCH 1/4] xen: xen-pciback: Replace GFP_ATOMIC with GFP_KERNEL in pcistub_probe

[Jia-Ju Bai <baijiaju1990@gmail.com>]

On 2018/4/10 23:01, Boris Ostrovsky wrote:
> On 04/10/2018 10:31 AM, Jia-Ju Bai wrote:
>>
>>
>> On 2018/4/10 22:27, Boris Ostrovsky wrote:
>>> On 04/09/2018 11:03 AM, Jia-Ju Bai wrote:
>>>> pcistub_probe() is never called in atomic context.
>>>> This function is only set as ".probe" in struct pci_driver.
>>>>
>>>> Despite never getting called from atomic context,
>>>> pcistub_probe() calls kmalloc() with GFP_ATOMIC,
>>>> which does not sleep for allocation.
>>>> GFP_ATOMIC is not necessary and can be replaced with GFP_KERNEL,
>>>> which can sleep and improve the possibility of sucessful allocation.
>>>>
>>>> This is found by a static analysis tool named DCNS written by myself.
>>>> And I also manually check it.
>>>>
>>>> Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
>>> What about use of GFP_ATOMIC in pcistub_reg_add()?
>> Thanks for your reply :)
>> I find pcistub_reg_add() is called by pcistub_quirk_add().
>> And pcistub_quirk_add() is called in the macro DRIVER_ATTR().
>> I am not sure whether DRIVER_ATTR() can make the function called in
>> atomic context,
>> so I do not analyze it in my tool.
> I don't see why it needs to be ATOMIC, it's sysfs access. Can you send a
> patch to fix it as well?

Okay, I will send a patch for it soon.
You can have a look :)


Best wishes,
Jia-Ju Bai