[Devel] [PATCH hci-8.1 v2 4/6] timens: freeze the offsets on the first join without the vDSO too

[Konstantin Khorenko]

> A time namespace's offsets may be written until the first task joins
> it; from then on they are read without a lock, so that join freezes
> them. The freeze sat in the code that fills the namespace's vDSO
> page, and since 1b6c89285d37 ("timens: Remove dependency on the vDSO")
> a kernel without a generic vDSO, User Mode Linux now, never froze: the
> owner could rewrite the offsets under the tasks already running there,
> and the clocks they read moved with them.
> 
> Freeze in timens_commit() itself and fill the vDSO page from there,
> where there is one.

Looks like this patch fixes the problem which exists in the mainstream as well,
so please
 - file a task and post it here for sending this patch to mainstream
 - send the patch to the mainstream, get the feedback
 - once mainstream applies the commit to some git tree - even unstable,
   resend this commit as a backport, i will apply it as well.

i.e. work in the "mainsteam first" for this commit.

You can send a next version of the series without this patch, i will take them.

-- 
Konstantin Khorenko <khorenko at virtuozzo.com>