From: Wenyu Huang huangwenyu5@huawei.com

hulk inclusion category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/IB7B5F

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After running the long-term stability test for a period of time, the UAF problem is triggered:

[ 9533.667062] dump_stack_lvl+0x47/0x80 [ 9533.667158] print_address_description.constprop.0+0x66/0x300 [ 9533.667346] print_report+0x3e/0x70 [ 9533.667436] kasan_report+0xb4/0xf0 [ 9533.667619] __update_blocked_fair+0x421/0x15c0 [ 9533.667804] update_blocked_averages+0x14d/0x360 [ 9533.668176] run_rebalance_domains+0x66/0xa0 [ 9533.668271] handle_softirqs+0x10e/0x4c0 [ 9533.668370] irq_exit_rcu+0xea/0x120 [ 9533.668458] sysvec_apic_timer_interrupt+0x72/0x90

The unthrottle_qos_sched_group adds the leaf_cfs_rq back to the leaf_cfs_rq and sets on_list to 1. When unthrottle_qos_sched_group is executed in free_fair_sched_group, the node is inserted into the linked list again and then freed. So it causes UAF.

Fixes: 926b9b0cd97e ("sched: Throttle qos cfs_rq when current cpu is running online task") Signed-off-by: Wenyu Huang huangwenyu5@huawei.com Signed-off-by: Liu Kai liukai284@huawei.com --- kernel/sched/fair.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index f1cd57e70f1f..13be1bd6cc53 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -14704,10 +14704,6 @@ void free_fair_sched_group(struct task_group *tg) int i;

for_each_possible_cpu(i) { -#ifdef CONFIG_QOS_SCHED - if (tg->cfs_rq && tg->cfs_rq[i]) - unthrottle_qos_sched_group(tg->cfs_rq[i]); -#endif if (tg->cfs_rq) kfree(tg->cfs_rq[i]); if (tg->se) @@ -14794,6 +14790,11 @@ void unregister_fair_sched_group(struct task_group *tg) if (tg->se[cpu]) remove_entity_load_avg(tg->se[cpu]);

+ #ifdef CONFIG_QOS_SCHED + if (tg->cfs_rq && tg->cfs_rq[cpu]) + unthrottle_qos_sched_group(tg->cfs_rq[cpu]); + #endif + /* * Only empty task groups can be destroyed; so we can speculatively * check on_list without danger of it being re-added.