From: Thomas Gleixner <tglx@linutronix.de> mainline inclusion from mainline-v6.13-rc1 commit 0f0d1b8e5010bfe1feeb4d78d137e41946a5370d category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/IDC9YK Reference: https://web.git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commi... -------------------------------- Instead of solving the underlying problem of the double invocation of __sched_fork() for idle tasks, sched-ext decided to hack around the issue by partially clearing out the entity struct to preserve the already enqueued node. A provided analysis and solution has been ignored for four months. Now that someone else has taken care of cleaning it up, remove the disgusting hack and clear out the full structure. Remove the comment in the structure declaration as well, as there is no requirement for @node being the last element anymore. Fixes: f0e1a0643a59 ("sched_ext: Implement BPF extensible scheduler class") Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Tejun Heo <tj@kernel.org> Link: https://lore.kernel.org/r/87ldy82wkc.ffs@tglx Signed-off-by: Zicheng Qu <quzicheng@huawei.com> --- include/linux/sched/ext.h | 1 - kernel/sched/ext.c | 7 +------ 2 files changed, 1 insertion(+), 7 deletions(-) diff --git a/include/linux/sched/ext.h b/include/linux/sched/ext.h index 65bc0a489cd2..1d70a9867fb1 100644 --- a/include/linux/sched/ext.h +++ b/include/linux/sched/ext.h @@ -199,7 +199,6 @@ struct sched_ext_entity { #ifdef CONFIG_EXT_GROUP_SCHED struct cgroup *cgrp_moving_from; #endif - /* must be the last field, see init_scx_entity() */ struct list_head tasks_node; }; diff --git a/kernel/sched/ext.c b/kernel/sched/ext.c index 6ac7ad474d11..882483c0b911 100644 --- a/kernel/sched/ext.c +++ b/kernel/sched/ext.c @@ -4093,12 +4093,7 @@ static void scx_ops_exit_task(struct task_struct *p) void init_scx_entity(struct sched_ext_entity *scx) { - /* - * init_idle() calls this function again after fork sequence is - * complete. Don't touch ->tasks_node as it's already linked. - */ - memset(scx, 0, offsetof(struct sched_ext_entity, tasks_node)); - + memset(scx, 0, sizeof(*scx)); INIT_LIST_HEAD(&scx->dsq_list.node); RB_CLEAR_NODE(&scx->dsq_priq); scx->sticky_cpu = -1; -- 2.34.1