Re: Regression with orderly_poweroff()

[Linus Torvalds]

On Tue, Mar 12, 2013 at 11:22 AM, Oleg Nesterov <oleg@xxxxxxxxxx> wrote:
>
> And how this can help? The real problem is not GFP_KERNEL.
> call_usermodehelper_exec(UMH_WAIT_EXEC) will block.

Well, it's probably a starting point.

You need to do the argument handling atomically, because you cannot
delay that in a workqueue (the arguments will be long gone by the time
the workqueue starts up). So I think the fix is a combination of your
and Lucas' code, where you first do the setup atomically (copying the
arguments and allocating that space with GFP_ATOMIC) and then you do a
workqueue to actually do the real work of the usermode helper thing.

                 Linus
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