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Diffstat (limited to 'kernel/cgroup.c')
-rw-r--r--kernel/cgroup.c75
1 files changed, 40 insertions, 35 deletions
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 2731d115d72..d9d5648f3cd 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -27,9 +27,11 @@
*/
#include <linux/cgroup.h>
+#include <linux/cred.h>
#include <linux/ctype.h>
#include <linux/errno.h>
#include <linux/fs.h>
+#include <linux/init_task.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/mm.h>
@@ -59,7 +61,7 @@
#include <linux/poll.h>
#include <linux/flex_array.h> /* used in cgroup_attach_proc */
-#include <asm/atomic.h>
+#include <linux/atomic.h>
static DEFINE_MUTEX(cgroup_mutex);
@@ -263,7 +265,7 @@ list_for_each_entry(_root, &roots, root_list)
/* the list of cgroups eligible for automatic release. Protected by
* release_list_lock */
static LIST_HEAD(release_list);
-static DEFINE_SPINLOCK(release_list_lock);
+static DEFINE_RAW_SPINLOCK(release_list_lock);
static void cgroup_release_agent(struct work_struct *work);
static DECLARE_WORK(release_agent_work, cgroup_release_agent);
static void check_for_release(struct cgroup *cgrp);
@@ -1514,6 +1516,7 @@ static struct dentry *cgroup_mount(struct file_system_type *fs_type,
struct cgroup *root_cgrp = &root->top_cgroup;
struct inode *inode;
struct cgroupfs_root *existing_root;
+ const struct cred *cred;
int i;
BUG_ON(sb->s_root != NULL);
@@ -1593,7 +1596,9 @@ static struct dentry *cgroup_mount(struct file_system_type *fs_type,
BUG_ON(!list_empty(&root_cgrp->children));
BUG_ON(root->number_of_cgroups != 1);
+ cred = override_creds(&init_cred);
cgroup_populate_dir(root_cgrp);
+ revert_creds(cred);
mutex_unlock(&cgroup_mutex);
mutex_unlock(&inode->i_mutex);
} else {
@@ -1697,7 +1702,6 @@ int cgroup_path(const struct cgroup *cgrp, char *buf, int buflen)
{
char *start;
struct dentry *dentry = rcu_dereference_check(cgrp->dentry,
- rcu_read_lock_held() ||
cgroup_lock_is_held());
if (!dentry || cgrp == dummytop) {
@@ -1723,7 +1727,6 @@ int cgroup_path(const struct cgroup *cgrp, char *buf, int buflen)
break;
dentry = rcu_dereference_check(cgrp->dentry,
- rcu_read_lock_held() ||
cgroup_lock_is_held());
if (!cgrp->parent)
continue;
@@ -2024,7 +2027,7 @@ int cgroup_attach_proc(struct cgroup *cgrp, struct task_struct *leader)
goto out_free_group_list;
/* prevent changes to the threadgroup list while we take a snapshot. */
- rcu_read_lock();
+ read_lock(&tasklist_lock);
if (!thread_group_leader(leader)) {
/*
* a race with de_thread from another thread's exec() may strip
@@ -2033,7 +2036,7 @@ int cgroup_attach_proc(struct cgroup *cgrp, struct task_struct *leader)
* throw this task away and try again (from cgroup_procs_write);
* this is "double-double-toil-and-trouble-check locking".
*/
- rcu_read_unlock();
+ read_unlock(&tasklist_lock);
retval = -EAGAIN;
goto out_free_group_list;
}
@@ -2054,7 +2057,7 @@ int cgroup_attach_proc(struct cgroup *cgrp, struct task_struct *leader)
} while_each_thread(leader, tsk);
/* remember the number of threads in the array for later. */
group_size = i;
- rcu_read_unlock();
+ read_unlock(&tasklist_lock);
/*
* step 1: check that we can legitimately attach to the cgroup.
@@ -2132,14 +2135,17 @@ int cgroup_attach_proc(struct cgroup *cgrp, struct task_struct *leader)
oldcgrp = task_cgroup_from_root(tsk, root);
if (cgrp == oldcgrp)
continue;
- /* attach each task to each subsystem */
- for_each_subsys(root, ss) {
- if (ss->attach_task)
- ss->attach_task(cgrp, tsk);
- }
/* if the thread is PF_EXITING, it can just get skipped. */
retval = cgroup_task_migrate(cgrp, oldcgrp, tsk, true);
- BUG_ON(retval != 0 && retval != -ESRCH);
+ if (retval == 0) {
+ /* attach each task to each subsystem */
+ for_each_subsys(root, ss) {
+ if (ss->attach_task)
+ ss->attach_task(cgrp, tsk);
+ }
+ } else {
+ BUG_ON(retval != -ESRCH);
+ }
}
/* nothing is sensitive to fork() after this point. */
@@ -3542,7 +3548,8 @@ static int cgroup_write_event_control(struct cgroup *cgrp, struct cftype *cft,
}
/* the process need read permission on control file */
- ret = file_permission(cfile, MAY_READ);
+ /* AV: shouldn't we check that it's been opened for read instead? */
+ ret = inode_permission(cfile->f_path.dentry->d_inode, MAY_READ);
if (ret < 0)
goto fail;
@@ -4010,11 +4017,11 @@ again:
finish_wait(&cgroup_rmdir_waitq, &wait);
clear_bit(CGRP_WAIT_ON_RMDIR, &cgrp->flags);
- spin_lock(&release_list_lock);
+ raw_spin_lock(&release_list_lock);
set_bit(CGRP_REMOVED, &cgrp->flags);
if (!list_empty(&cgrp->release_list))
list_del_init(&cgrp->release_list);
- spin_unlock(&release_list_lock);
+ raw_spin_unlock(&release_list_lock);
cgroup_lock_hierarchy(cgrp->root);
/* delete this cgroup from parent->children */
@@ -4667,13 +4674,13 @@ static void check_for_release(struct cgroup *cgrp)
* already queued for a userspace notification, queue
* it now */
int need_schedule_work = 0;
- spin_lock(&release_list_lock);
+ raw_spin_lock(&release_list_lock);
if (!cgroup_is_removed(cgrp) &&
list_empty(&cgrp->release_list)) {
list_add(&cgrp->release_list, &release_list);
need_schedule_work = 1;
}
- spin_unlock(&release_list_lock);
+ raw_spin_unlock(&release_list_lock);
if (need_schedule_work)
schedule_work(&release_agent_work);
}
@@ -4725,7 +4732,7 @@ static void cgroup_release_agent(struct work_struct *work)
{
BUG_ON(work != &release_agent_work);
mutex_lock(&cgroup_mutex);
- spin_lock(&release_list_lock);
+ raw_spin_lock(&release_list_lock);
while (!list_empty(&release_list)) {
char *argv[3], *envp[3];
int i;
@@ -4734,7 +4741,7 @@ static void cgroup_release_agent(struct work_struct *work)
struct cgroup,
release_list);
list_del_init(&cgrp->release_list);
- spin_unlock(&release_list_lock);
+ raw_spin_unlock(&release_list_lock);
pathbuf = kmalloc(PAGE_SIZE, GFP_KERNEL);
if (!pathbuf)
goto continue_free;
@@ -4764,9 +4771,9 @@ static void cgroup_release_agent(struct work_struct *work)
continue_free:
kfree(pathbuf);
kfree(agentbuf);
- spin_lock(&release_list_lock);
+ raw_spin_lock(&release_list_lock);
}
- spin_unlock(&release_list_lock);
+ raw_spin_unlock(&release_list_lock);
mutex_unlock(&cgroup_mutex);
}
@@ -4813,8 +4820,7 @@ unsigned short css_id(struct cgroup_subsys_state *css)
* on this or this is under rcu_read_lock(). Once css->id is allocated,
* it's unchanged until freed.
*/
- cssid = rcu_dereference_check(css->id,
- rcu_read_lock_held() || atomic_read(&css->refcnt));
+ cssid = rcu_dereference_check(css->id, atomic_read(&css->refcnt));
if (cssid)
return cssid->id;
@@ -4826,8 +4832,7 @@ unsigned short css_depth(struct cgroup_subsys_state *css)
{
struct css_id *cssid;
- cssid = rcu_dereference_check(css->id,
- rcu_read_lock_held() || atomic_read(&css->refcnt));
+ cssid = rcu_dereference_check(css->id, atomic_read(&css->refcnt));
if (cssid)
return cssid->depth;
@@ -4878,9 +4883,9 @@ void free_css_id(struct cgroup_subsys *ss, struct cgroup_subsys_state *css)
rcu_assign_pointer(id->css, NULL);
rcu_assign_pointer(css->id, NULL);
- spin_lock(&ss->id_lock);
+ write_lock(&ss->id_lock);
idr_remove(&ss->idr, id->id);
- spin_unlock(&ss->id_lock);
+ write_unlock(&ss->id_lock);
kfree_rcu(id, rcu_head);
}
EXPORT_SYMBOL_GPL(free_css_id);
@@ -4906,10 +4911,10 @@ static struct css_id *get_new_cssid(struct cgroup_subsys *ss, int depth)
error = -ENOMEM;
goto err_out;
}
- spin_lock(&ss->id_lock);
+ write_lock(&ss->id_lock);
/* Don't use 0. allocates an ID of 1-65535 */
error = idr_get_new_above(&ss->idr, newid, 1, &myid);
- spin_unlock(&ss->id_lock);
+ write_unlock(&ss->id_lock);
/* Returns error when there are no free spaces for new ID.*/
if (error) {
@@ -4924,9 +4929,9 @@ static struct css_id *get_new_cssid(struct cgroup_subsys *ss, int depth)
return newid;
remove_idr:
error = -ENOSPC;
- spin_lock(&ss->id_lock);
+ write_lock(&ss->id_lock);
idr_remove(&ss->idr, myid);
- spin_unlock(&ss->id_lock);
+ write_unlock(&ss->id_lock);
err_out:
kfree(newid);
return ERR_PTR(error);
@@ -4938,7 +4943,7 @@ static int __init_or_module cgroup_init_idr(struct cgroup_subsys *ss,
{
struct css_id *newid;
- spin_lock_init(&ss->id_lock);
+ rwlock_init(&ss->id_lock);
idr_init(&ss->idr);
newid = get_new_cssid(ss, 0);
@@ -5033,9 +5038,9 @@ css_get_next(struct cgroup_subsys *ss, int id,
* scan next entry from bitmap(tree), tmpid is updated after
* idr_get_next().
*/
- spin_lock(&ss->id_lock);
+ read_lock(&ss->id_lock);
tmp = idr_get_next(&ss->idr, &tmpid);
- spin_unlock(&ss->id_lock);
+ read_unlock(&ss->id_lock);
if (!tmp)
break;
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2025-02-20 00:47:30 +0000