From 3ebd7b38415e49080c1591b7ca141f87a81bdbe5 Mon Sep 17 00:00:00 2001 From: Quentin Perret Date: Tue, 27 Jul 2021 11:11:01 +0100 Subject: 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if sched_getattr() is then called on the task, __getparam_dl() will override kattr.sched_flags with the now out-of-date copy in dl_se-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 Signed-off-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/r/20210727101103.2729607-2-qperret@google.com Signed-off-by: Sasha Levin --- kernel/sched/sched.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'kernel/sched/sched.h') 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 -- cgit v1.2.3