From 85dd3f61203c5cfa72b308ff327b5fbf3fc1ce5e Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Mon, 29 Mar 2021 15:18:35 +0200 Subject: [PATCH] sched: Inherit task cookie on fork() Note that sched_core_fork() is called from under tasklist_lock, and not from sched_fork() earlier. This avoids a few races later. Signed-off-by: Peter Zijlstra (Intel) Tested-by: Don Hiatt Tested-by: Hongyu Ning Tested-by: Vincent Guittot Link: https://lkml.kernel.org/r/20210422123308.980003687@infradead.org --- include/linux/sched.h | 2 ++ kernel/fork.c | 3 +++ kernel/sched/core_sched.c | 6 ++++++ 3 files changed, 11 insertions(+) diff --git a/include/linux/sched.h b/include/linux/sched.h index eab3f7c4251b..fba47e52e482 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -2181,8 +2181,10 @@ const struct cpumask *sched_trace_rd_span(struct root_domain *rd); #ifdef CONFIG_SCHED_CORE extern void sched_core_free(struct task_struct *tsk); +extern void sched_core_fork(struct task_struct *p); #else static inline void sched_core_free(struct task_struct *tsk) { } +static inline void sched_core_fork(struct task_struct *p) { } #endif #endif diff --git a/kernel/fork.c b/kernel/fork.c index d16c60c9daca..e7fd928fcafe 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -2251,6 +2251,8 @@ static __latent_entropy struct task_struct *copy_process( klp_copy_process(p); + sched_core_fork(p); + spin_lock(¤t->sighand->siglock); /* @@ -2338,6 +2340,7 @@ static __latent_entropy struct task_struct *copy_process( return p; bad_fork_cancel_cgroup: + sched_core_free(p); spin_unlock(¤t->sighand->siglock); write_unlock_irq(&tasklist_lock); cgroup_cancel_fork(p, args); diff --git a/kernel/sched/core_sched.c b/kernel/sched/core_sched.c index 8d0869a9eb8c..dcbbeaefaaa3 100644 --- a/kernel/sched/core_sched.c +++ b/kernel/sched/core_sched.c @@ -103,6 +103,12 @@ static unsigned long sched_core_clone_cookie(struct task_struct *p) return cookie; } +void sched_core_fork(struct task_struct *p) +{ + RB_CLEAR_NODE(&p->core_node); + p->core_cookie = sched_core_clone_cookie(current); +} + void sched_core_free(struct task_struct *p) { sched_core_put_cookie(p->core_cookie);