| Date | Thu, 22 Apr 2021 14:05:16 +0200 | From | Peter Zijlstra <> | Subject | [PATCH 17/19] sched: Inherit task cookie on fork() |
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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) <peterz@infradead.org> --- include/linux/sched.h | 2 ++ kernel/fork.c | 3 +++ kernel/sched/core_sched.c | 6 ++++++ 3 files changed, 11 insertions(+)
--- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -2172,8 +2172,10 @@ const struct cpumask *sched_trace_rd_spa #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 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -2249,6 +2249,8 @@ static __latent_entropy struct task_stru klp_copy_process(p); + sched_core_fork(p); + spin_lock(¤t->sighand->siglock); /* @@ -2336,6 +2338,7 @@ static __latent_entropy struct task_stru 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); --- a/kernel/sched/core_sched.c +++ b/kernel/sched/core_sched.c @@ -100,6 +100,12 @@ static unsigned long sched_core_clone_co 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);
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