Messages in this thread | | | Date | Wed, 28 Jul 2021 10:39:38 +0100 | From | Quentin Perret <> | Subject | Re: [PATCH 2/2] sched: Don't report SCHED_FLAG_SUGOV in sched_getattr() |
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On Wednesday 28 Jul 2021 at 11:12:03 (+0200), Juri Lelli wrote: > Hi Quentin, > > On 27/07/21 11:11, Quentin Perret wrote: > > SCHED_FLAG_SUGOV is supposed to be a kernel-only flag that userspace > > cannot interact with. However, sched_getattr() currently reports it > > in sched_flags if called on a sugov worker even though it is not > > actually defined in a UAPI header. To avoid this, make sure to > > clean-up the sched_flags field in sched_getattr() before returning to > > userspace. > > > > Signed-off-by: Quentin Perret <qperret@google.com> > > --- > > kernel/sched/core.c | 1 + > > 1 file changed, 1 insertion(+) > > > > diff --git a/kernel/sched/core.c b/kernel/sched/core.c > > index 2d9ff40f4661..d8f489dcc383 100644 > > --- a/kernel/sched/core.c > > +++ b/kernel/sched/core.c > > @@ -7535,6 +7535,7 @@ SYSCALL_DEFINE4(sched_getattr, pid_t, pid, struct sched_attr __user *, uattr, > > kattr.sched_priority = p->rt_priority; > > else > > kattr.sched_nice = task_nice(p); > > + kattr.sched_flags &= SCHED_FLAG_ALL; > > Maybe we can do this in the previous patch so that it's kept confined to > deadline bits?
That works too, it just felt like this could happen again if we start using non-standard flags outside of deadline for any reason at some point in the future. But no strong opinion really.
Cheers, Quentin
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