diff options
| author | Quentin Perret <qperret@google.com> | 2021-07-27 11:11:01 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-09-15 09:50:24 +0200 |
| commit | 3ebd7b38415e49080c1591b7ca141f87a81bdbe5 (patch) | |
| tree | 87677acb82058e764edddc8b2474b84a61951580 /kernel | |
| parent | 8c4d94db5acd99b5d64d0116fc12276266ee5be0 (diff) | |
sched/deadline: Fix reset_on_fork reporting of DL tasks
[ Upstream commit f95091536f78971b269ec321b057b8d630b0ad8a ]
It is possible for sched_getattr() to incorrectly report the state of
the reset_on_fork flag when called on a deadline task.
Indeed, if the flag was set on a deadline task using sched_setattr()
with flags (SCHED_FLAG_RESET_ON_FORK | SCHED_FLAG_KEEP_PARAMS), then
p->sched_reset_on_fork will be set, but __setscheduler() will bail out
early, which means that the dl_se->flags will not get updated by
__setscheduler_params()->__setparam_dl(). Consequently, if
sched_getattr() is then called on the task, __getparam_dl() will
override kattr.sched_flags with the now out-of-date copy in dl_se->flags
and report the stale value to userspace.
To fix this, make sure to only copy the flags that are relevant to
sched_deadline to and from the dl_se->flags field.
Signed-off-by: Quentin Perret <qperret@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20210727101103.2729607-2-qperret@google.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/sched/deadline.c | 7 | ||||
| -rw-r--r-- | kernel/sched/sched.h | 2 |
2 files changed, 6 insertions, 3 deletions
diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c index 6b98c1fe6e7f..82c76196a9d2 100644 --- a/kernel/sched/deadline.c +++ b/kernel/sched/deadline.c @@ -2703,7 +2703,7 @@ void __setparam_dl(struct task_struct *p, const struct sched_attr *attr) dl_se->dl_runtime = attr->sched_runtime; dl_se->dl_deadline = attr->sched_deadline; dl_se->dl_period = attr->sched_period ?: dl_se->dl_deadline; - dl_se->flags = attr->sched_flags; + dl_se->flags = attr->sched_flags & SCHED_DL_FLAGS; dl_se->dl_bw = to_ratio(dl_se->dl_period, dl_se->dl_runtime); dl_se->dl_density = to_ratio(dl_se->dl_deadline, dl_se->dl_runtime); } @@ -2716,7 +2716,8 @@ void __getparam_dl(struct task_struct *p, struct sched_attr *attr) attr->sched_runtime = dl_se->dl_runtime; attr->sched_deadline = dl_se->dl_deadline; attr->sched_period = dl_se->dl_period; - attr->sched_flags = dl_se->flags; + attr->sched_flags &= ~SCHED_DL_FLAGS; + attr->sched_flags |= dl_se->flags; } /* @@ -2813,7 +2814,7 @@ bool dl_param_changed(struct task_struct *p, const struct sched_attr *attr) if (dl_se->dl_runtime != attr->sched_runtime || dl_se->dl_deadline != attr->sched_deadline || dl_se->dl_period != attr->sched_period || - dl_se->flags != attr->sched_flags) + dl_se->flags != (attr->sched_flags & SCHED_DL_FLAGS)) return true; return false; diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index 39112ac7ab34..08db8e095e48 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -226,6 +226,8 @@ static inline void update_avg(u64 *avg, u64 sample) */ #define SCHED_FLAG_SUGOV 0x10000000 +#define SCHED_DL_FLAGS (SCHED_FLAG_RECLAIM | SCHED_FLAG_DL_OVERRUN | SCHED_FLAG_SUGOV) + static inline bool dl_entity_is_special(struct sched_dl_entity *dl_se) { #ifdef CONFIG_CPU_FREQ_GOV_SCHEDUTIL |