Re: [PATCH/RFC] - support inheritance of mlocks across fork/exec

["KOSAKI Motohiro" <kosaki.motohiro@jp.fujitsu.com>]

Hi

> Hello, Kosaki-san:
>
> Thanks for looking at this.  I think you mean that:
>
> 1) don't allow MCL_INHERIT | MCL_RECURSIVE without either MCL_CURRENT or
> MCL_FUTURE, and
>
> 2) MCL_RECURSIVE without MCL_INHERIT does not make sense, either.
>
> Is this correct?

Yup. you describe just my opnion.
thanks.


> I guess I agree with you.  As is stands, my patch would allow
> MCL_INHERIT[|MCL_RECURSIVE] to sneak through with neither MCL_CURRENT
> nor MCL_FUTURE set.  Looks like this would result in mlock_fixup() being
> called with a newflags that does not containing VM_LOCKED.  This would
> be treated as munlockall().   Not good.  Your first check would catch
> this.
>
> The second condition would be a no-op, I think.  We only look at look
> for MCL_RECURSIVE in mm->mcl_inherit when mcl_inherit is non-zero; and
> we only set mcl_inherit when MCL_INHERIT is specified.  But, if the
> caller specified MCL_RECURSIVE, they probably intended something to
> happen, and since it won't, best to return an error.
>
> I'll fix this up and send it out to the wider distribution that Andrew
> requested.
>
> Thanks, again.

I am one of most appointee from this patch :)

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>