sched: Inherit task cookie on fork()

mainline inclusion
from mainline-v5.14-rc1
commit 85dd3f61
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I5OOWG
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=85dd3f61203c5cfa72b308ff327b5fbf3fc1ce5e

--------------------------------------------------------------------------

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: NPeter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: NDon Hiatt <dhiatt@digitalocean.com>
Tested-by: NHongyu Ning <hongyu.ning@linux.intel.com>
Tested-by: NVincent Guittot <vincent.guittot@linaro.org>
Link: https://lkml.kernel.org/r/20210422123308.980003687@infradead.orgSigned-off-by: NLin Shengwang <linshengwang1@huawei.com>
Reviewed-by: Nlihua <hucool.lihua@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

include/linux/sched.h

@@ -2175,8 +2175,10 @@ 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
 
 #ifdef CONFIG_QOS_SCHED

kernel/fork.c

@@ -2278,6 +2278,8 @@ static __latent_entropy struct task_struct *copy_process(
 
 	klp_copy_process(p);
 
+	sched_core_fork(p);
+
 	spin_lock(&current->sighand->siglock);
 
 	/*
@@ -2364,6 +2366,7 @@ static __latent_entropy struct task_struct *copy_process(
 	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);

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);