Commit 9cd6f55e authored by Kang Chen's avatar Kang Chen Committed by openeuler-sync-bot
Browse files

mm: oom: move memcg_print_bad_task() out of mem_cgroup_scan_tasks() 

hulk inclusion
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/I6NYW4


CVE: NA

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

raw call flow:

oom_kill_process
  -> mem_cgroup_scan_tasks(.., .., message)
    -> memcg_print_bad_task(message, ..)

message is "const char*" type, and incorrectly cast to
"oom_control*" type in memcg_print_bad_task.

Fix it by moving memcg_print_bad_task out of mem_cgroup_scan_tasks
and call it in select_bad_process and dump_tasks. Furthermore,
use struct oom_control* directly and remove the useless parm `ret`.

Reviewed-by: default avatarKefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: default avatarKang Chen <void0red@hust.edu.cn>
(cherry picked from commit 789038c7)
parent 2c572019

include/linux/memcontrol.h

+1 −1
Original line number Diff line number Diff line
@@ -417,7 +417,7 @@ DECLARE_STATIC_KEY_FALSE(memcg_qos_stat_key); 


bool memcg_low_priority_scan_tasks(int (*)(struct task_struct *, void *),

				   void *);

void memcg_print_bad_task(void *arg, int ret);

void memcg_print_bad_task(struct oom_control *oc);

extern int sysctl_memcg_qos_handler(struct ctl_table *table,

		int write, void __user *buffer, size_t *length, loff_t *ppos);

#endif

mm/memcontrol.c

+9 −7
Original line number Diff line number Diff line
@@ -1222,9 +1222,6 @@ int mem_cgroup_scan_tasks(struct mem_cgroup *memcg, 
			break;

		}

	}

#ifdef CONFIG_MEMCG_QOS

	memcg_print_bad_task(arg, ret);

#endif

	return ret;

}
@@ -4012,14 +4009,12 @@ bool memcg_low_priority_scan_tasks(int (*fn)(struct task_struct *, void *), 
	return oc->chosen ? true : false;

}



void memcg_print_bad_task(void *arg, int ret)

void memcg_print_bad_task(struct oom_control *oc)

{

	struct oom_control *oc = arg;



	if (!static_branch_likely(&memcg_qos_stat_key))

		return;



	if (!ret && oc->chosen) {

	if (oc->chosen) {

		struct mem_cgroup *memcg;



		memcg = mem_cgroup_from_task(oc->chosen);
@@ -4050,6 +4045,13 @@ int sysctl_memcg_qos_handler(struct ctl_table *table, int write, 


	return ret;

}



#else



void memcg_print_bad_task(struct oom_control *oc)

{

}



#endif



#ifdef CONFIG_NUMA

mm/oom_kill.c

+8 −6
Original line number Diff line number Diff line
@@ -408,9 +408,10 @@ static void select_bad_process(struct oom_control *oc) 
{

	oc->chosen_points = LONG_MIN;



	if (is_memcg_oom(oc))

		mem_cgroup_scan_tasks(oc->memcg, oom_evaluate_task, oc);

	else {

	if (is_memcg_oom(oc)) {

		if (!mem_cgroup_scan_tasks(oc->memcg, oom_evaluate_task, oc))

			memcg_print_bad_task(oc);

	} else {

		struct task_struct *p;



#ifdef CONFIG_MEMCG_QOS
@@ -473,9 +474,10 @@ static void dump_tasks(struct oom_control *oc) 
	pr_info("Tasks state (memory values in pages):\n");

	pr_info("[  pid  ]   uid  tgid total_vm      rss pgtables_bytes swapents oom_score_adj name\n");



	if (is_memcg_oom(oc))

		mem_cgroup_scan_tasks(oc->memcg, dump_task, oc);

	else {

	if (is_memcg_oom(oc)) {

		if (!mem_cgroup_scan_tasks(oc->memcg, dump_task, oc))

			memcg_print_bad_task(oc);

	} else {

		struct task_struct *p;



		rcu_read_lock();