From: "Paul E. McKenney" <paulmck@kernel.org> stable inclusion from stable-5.10.50 commit 728f23e53c65a90440fe16b270cdff4401433c38 bugzilla: 174522 https://gitee.com/openeuler/kernel/issues/I4DNFY Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- [ Upstream commit 8e4b1d2bc198e34b48fc7cc3a3c5a2fcb269e271 ] Currently, rcu_spawn_core_kthreads() is invoked via an early_initcall(), which works, except that rcu_spawn_gp_kthread() is also invoked via an early_initcall() and rcu_spawn_core_kthreads() relies on adjustments to kthread_prio that are carried out by rcu_spawn_gp_kthread(). There is no guaranttee of ordering among early_initcall() handlers, and thus no guarantee that kthread_prio will be properly checked and range-limited at the time that rcu_spawn_core_kthreads() needs it. In most cases, this bug is harmless. After all, the only reason that rcu_spawn_gp_kthread() adjusts the value of kthread_prio is if the user specified a nonsensical value for this boot parameter, which experience indicates is rare. Nevertheless, a bug is a bug. This commit therefore causes the rcu_spawn_core_kthreads() function to be invoked directly from rcu_spawn_gp_kthread() after any needed adjustments to kthread_prio have been carried out. Fixes: 48d07c04b4cc ("rcu: Enable elimination of Tree-RCU softirq processing") Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Chen Jun <chenjun102@huawei.com> Acked-by: Weilong Chen <chenweilong@huawei.com> Signed-off-by: Chen Jun <chenjun102@huawei.com> --- kernel/rcu/tree.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 61e250cdd7c9..45b60e997461 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -2837,7 +2837,6 @@ static int __init rcu_spawn_core_kthreads(void) "%s: Could not start rcuc kthread, OOM is now expected behavior\n", __func__); return 0; } -early_initcall(rcu_spawn_core_kthreads); /* * Handle any core-RCU processing required by a call_rcu() invocation. @@ -4273,6 +4272,7 @@ static int __init rcu_spawn_gp_kthread(void) wake_up_process(t); rcu_spawn_nocb_kthreads(); rcu_spawn_boost_kthreads(); + rcu_spawn_core_kthreads(); return 0; } early_initcall(rcu_spawn_gp_kthread); -- 2.20.1