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Subject[PATCH 17/19] 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) <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(&current->sighand->siglock);

/*
@@ -2336,6 +2338,7 @@ static __latent_entropy struct task_stru
return p;

bad_fork_cancel_cgroup:
+ sched_core_free(p);
spin_unlock(&current->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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