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authorLinus Torvalds <torvalds@linux-foundation.org>2018-01-08 11:13:08 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2018-01-08 11:13:08 -0800
commit29f7e499413aab1d33a5313147d2f7e026f67d7c (patch)
tree5d75d626802f67f023ad66fb20dc3906c70fb782
parentb2cd1df66037e7c4697c7e40496bf7e4a5e16a2d (diff)
parent74d0833c659a8a54735e5efdd44f4b225af68586 (diff)
downloadlinux-29f7e499413aab1d33a5313147d2f7e026f67d7c.tar.bz2
Merge branch 'for-4.15-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
Pull cgroup fixes from Tejun Heo: "This contains fixes for the following two non-trivial issues: - The task iterator got broken while adding thread mode support for v4.14. It was less visible because it only triggers when both cgroup1 and cgroup2 hierarchies are in use. The recent versions of systemd uses cgroup2 for process management even when cgroup1 is used for resource control exposing this issue. - cpuset CPU hotplug path could deadlock when racing against exits. There also are two patches to replace unlimited strcpy() usages with strlcpy()" * 'for-4.15-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: cgroup: fix css_task_iter crash on CSS_TASK_ITER_PROC cgroup: Fix deadlock in cpu hotplug path cgroup: use strlcpy() instead of strscpy() to avoid spurious warning cgroup: avoid copying strings longer than the buffers
-rw-r--r--kernel/cgroup/cgroup-v1.c6
-rw-r--r--kernel/cgroup/cgroup.c20
2 files changed, 14 insertions, 12 deletions
diff --git a/kernel/cgroup/cgroup-v1.c b/kernel/cgroup/cgroup-v1.c
index 024085daab1a..a2c05d2476ac 100644
--- a/kernel/cgroup/cgroup-v1.c
+++ b/kernel/cgroup/cgroup-v1.c
@@ -123,7 +123,11 @@ int cgroup_transfer_tasks(struct cgroup *to, struct cgroup *from)
*/
do {
css_task_iter_start(&from->self, 0, &it);
- task = css_task_iter_next(&it);
+
+ do {
+ task = css_task_iter_next(&it);
+ } while (task && (task->flags & PF_EXITING));
+
if (task)
get_task_struct(task);
css_task_iter_end(&it);
diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
index 0b1ffe147f24..2cf06c274e4c 100644
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -1397,7 +1397,7 @@ static char *cgroup_file_name(struct cgroup *cgrp, const struct cftype *cft,
cgroup_on_dfl(cgrp) ? ss->name : ss->legacy_name,
cft->name);
else
- strncpy(buf, cft->name, CGROUP_FILE_NAME_MAX);
+ strlcpy(buf, cft->name, CGROUP_FILE_NAME_MAX);
return buf;
}
@@ -1864,9 +1864,9 @@ void init_cgroup_root(struct cgroup_root *root, struct cgroup_sb_opts *opts)
root->flags = opts->flags;
if (opts->release_agent)
- strcpy(root->release_agent_path, opts->release_agent);
+ strlcpy(root->release_agent_path, opts->release_agent, PATH_MAX);
if (opts->name)
- strcpy(root->name, opts->name);
+ strlcpy(root->name, opts->name, MAX_CGROUP_ROOT_NAMELEN);
if (opts->cpuset_clone_children)
set_bit(CGRP_CPUSET_CLONE_CHILDREN, &root->cgrp.flags);
}
@@ -4125,26 +4125,24 @@ static void css_task_iter_advance_css_set(struct css_task_iter *it)
static void css_task_iter_advance(struct css_task_iter *it)
{
- struct list_head *l = it->task_pos;
+ struct list_head *next;
lockdep_assert_held(&css_set_lock);
- WARN_ON_ONCE(!l);
-
repeat:
/*
* Advance iterator to find next entry. cset->tasks is consumed
* first and then ->mg_tasks. After ->mg_tasks, we move onto the
* next cset.
*/
- l = l->next;
+ next = it->task_pos->next;
- if (l == it->tasks_head)
- l = it->mg_tasks_head->next;
+ if (next == it->tasks_head)
+ next = it->mg_tasks_head->next;
- if (l == it->mg_tasks_head)
+ if (next == it->mg_tasks_head)
css_task_iter_advance_css_set(it);
else
- it->task_pos = l;
+ it->task_pos = next;
/* if PROCS, skip over tasks which aren't group leaders */
if ((it->flags & CSS_TASK_ITER_PROCS) && it->task_pos &&