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

[Jia-Ju Bai <baijiaju1990@xxxxxxxxx>]

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@xxxxxxxxx>
> > > 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

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