127 lines
4.2 KiB
Diff
127 lines
4.2 KiB
Diff
From 1d5f6069f6212c51aa56b64922e60ec4eb3c0e3a Mon Sep 17 00:00:00 2001
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From: ZhangPeng <zhangpeng362@huawei.com>
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Date: Tue, 24 Dec 2024 16:47:53 +0800
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Subject: [PATCH 17/23] Revert "cgroup: Make operations on the cgroup root_list
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RCU safe"
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hulk inclusion
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category: feature
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bugzilla: https://gitee.com/openeuler/kernel/issues/IBDFAV
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----------------------------------------------------------------------
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This reverts commit 486eff6ae48b78edc20a4e51596f332c20f2f75f.
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Signed-off-by: ZhangPeng <zhangpeng362@huawei.com>
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---
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include/linux/cgroup-defs.h | 1 -
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kernel/cgroup/cgroup-internal.h | 3 +--
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kernel/cgroup/cgroup.c | 23 +++++++----------------
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3 files changed, 8 insertions(+), 19 deletions(-)
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diff --git a/include/linux/cgroup-defs.h b/include/linux/cgroup-defs.h
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index 05ece896af7d..6e3227a688de 100644
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--- a/include/linux/cgroup-defs.h
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+++ b/include/linux/cgroup-defs.h
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@@ -591,7 +591,6 @@ struct cgroup_root {
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/* A list running through the active hierarchies */
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struct list_head root_list;
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- struct rcu_head rcu;
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/* Hierarchy-specific flags */
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unsigned int flags;
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diff --git a/kernel/cgroup/cgroup-internal.h b/kernel/cgroup/cgroup-internal.h
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index f5fb12890645..96a9bd2c26f0 100644
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--- a/kernel/cgroup/cgroup-internal.h
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+++ b/kernel/cgroup/cgroup-internal.h
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@@ -170,8 +170,7 @@ extern struct list_head cgroup_roots;
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/* iterate across the hierarchies */
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#define for_each_root(root) \
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- list_for_each_entry_rcu((root), &cgroup_roots, root_list, \
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- lockdep_is_held(&cgroup_mutex))
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+ list_for_each_entry((root), &cgroup_roots, root_list)
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/**
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* for_each_subsys - iterate all enabled cgroup subsystems
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diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
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index c26a9b3a3576..52fe6ba2fefd 100644
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--- a/kernel/cgroup/cgroup.c
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+++ b/kernel/cgroup/cgroup.c
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@@ -1315,7 +1315,7 @@ static void cgroup_exit_root_id(struct cgroup_root *root)
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void cgroup_free_root(struct cgroup_root *root)
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{
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- kfree_rcu(root, rcu);
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+ kfree(root);
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}
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static void cgroup_destroy_root(struct cgroup_root *root)
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@@ -1348,7 +1348,7 @@ static void cgroup_destroy_root(struct cgroup_root *root)
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spin_unlock_irq(&css_set_lock);
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if (!list_empty(&root->root_list)) {
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- list_del_rcu(&root->root_list);
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+ list_del(&root->root_list);
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cgroup_root_count--;
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}
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@@ -1388,15 +1388,7 @@ static inline struct cgroup *__cset_cgroup_from_root(struct css_set *cset,
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}
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}
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- /*
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- * If cgroup_mutex is not held, the cgrp_cset_link will be freed
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- * before we remove the cgroup root from the root_list. Consequently,
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- * when accessing a cgroup root, the cset_link may have already been
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- * freed, resulting in a NULL res_cgroup. However, by holding the
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- * cgroup_mutex, we ensure that res_cgroup can't be NULL.
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- * If we don't hold cgroup_mutex in the caller, we must do the NULL
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- * check.
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- */
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+ BUG_ON(!res_cgroup);
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return res_cgroup;
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}
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@@ -1455,6 +1447,7 @@ static struct cgroup *current_cgns_cgroup_dfl(void)
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static struct cgroup *cset_cgroup_from_root(struct css_set *cset,
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struct cgroup_root *root)
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{
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+ lockdep_assert_held(&cgroup_mutex);
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lockdep_assert_held(&css_set_lock);
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return __cset_cgroup_from_root(cset, root);
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@@ -1462,9 +1455,7 @@ static struct cgroup *cset_cgroup_from_root(struct css_set *cset,
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/*
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* Return the cgroup for "task" from the given hierarchy. Must be
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- * called with css_set_lock held to prevent task's groups from being modified.
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- * Must be called with either cgroup_mutex or rcu read lock to prevent the
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- * cgroup root from being destroyed.
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+ * called with cgroup_mutex and css_set_lock held.
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*/
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struct cgroup *task_cgroup_from_root(struct task_struct *task,
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struct cgroup_root *root)
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@@ -2039,7 +2030,7 @@ void init_cgroup_root(struct cgroup_fs_context *ctx)
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struct cgroup_root *root = ctx->root;
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struct cgroup *cgrp = &root->cgrp;
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- INIT_LIST_HEAD_RCU(&root->root_list);
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+ INIT_LIST_HEAD(&root->root_list);
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atomic_set(&root->nr_cgrps, 1);
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cgrp->root = root;
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init_cgroup_housekeeping(cgrp);
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@@ -2123,7 +2114,7 @@ int cgroup_setup_root(struct cgroup_root *root, u16 ss_mask)
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* care of subsystems' refcounts, which are explicitly dropped in
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* the failure exit path.
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*/
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- list_add_rcu(&root->root_list, &cgroup_roots);
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+ list_add(&root->root_list, &cgroup_roots);
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cgroup_root_count++;
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/*
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--
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2.25.1
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