hulk inclusion category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I8ZBLR CVE: NA

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In some cases, when performing the CPU continuous offline operation, hungtask will be reported. The error stack is as follows: Call track: __switch_to+0xc4/0x160 __schedule+0x8a4/0xcc0 schedule+0x58/0xf0 percpu_rwsem_wait+0xac/0x1c0 __percpu_down_read+0x44/0x100 cpus_read_lock+0x5c/0x70 static_key_disable+0x20/0x48 sched_init_numa+0x588/0x5e8 sched_update_numa+0x88/0xa0 sched_cpu_deactivate+0x138/0x2b8 cpuhp_invoke_callback+0x13c/0x5a0 cpuhp_thread_fun+0x108/0x1b0 smpboot_thread_fn+0x14c/0x198 kthread+0xf0/0x108 ret_from_fork+0x10/0x20

Before calling check_node_limit(), cpus hotplug write lock has been locked, and static_branch_disable() will try to get cpus hotplug read lock, it cause a deadlock issue. To fix it, use static_branch_disable_cpuslocked to replace static_branch_disable in check_node_limit to avoid the deadlock issue.

Fixes: c0830508683b ("sched/fair: disable stealing if too many NUMA nodes") Signed-off-by: Cheng Yu serein.chengyu@huawei.com --- kernel/sched/topology.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c index 6e53175382ce..5dca59dfea85 100644 --- a/kernel/sched/topology.c +++ b/kernel/sched/topology.c @@ -1880,7 +1880,7 @@ static void check_node_limit(void) if (sched_steal_node_limit == 0) sched_steal_node_limit = SCHED_STEAL_NODE_LIMIT_DEFAULT; if (n > sched_steal_node_limit) { - static_branch_disable(&sched_steal_allow); + static_branch_disable_cpuslocked(&sched_steal_allow); pr_debug("Suppressing sched STEAL. To enable, reboot with sched_steal_node_limit=%d", n); } }