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Merge branch 'for-5.6-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup 

Pull cgroup fixes from Tejun Heo:

 - cgroup.procs listing related fixes.

   It didn't interlock properly with exiting tasks leaving a short
   window where a cgroup has empty cgroup.procs but still can't be
   removed and misbehaved on short reads.

 - psi_show() crash fix on 32bit ino archs

 - Empty release_agent handling fix

* 'for-5.6-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
  cgroup1: don't call release_agent when it is ""
  cgroup: fix psi_show() crash on 32bit ino archs
  cgroup: Iterate tasks that did not finish do_exit()
  cgroup: cgroup_procs_next should increase position index
  cgroup-v1: cgroup_pidlist_next should update position index
This commit is contained in:
Linus Torvalds 2020-03-10 15:05:45 -07:00
parent 2c1aca4bd3 2e5383d790
commit e941484541
3 changed files with 29 additions and 14 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
include/linux/cgroup.h
View File

@ -62,6 +62,7 @@ struct css_task_iter {
struct list_head *mg_tasks_head;
struct list_head *dying_tasks_head;
struct list_head *cur_tasks_head;
struct css_set *cur_cset;
struct css_set *cur_dcset;
struct task_struct *cur_task;

3
kernel/cgroup/cgroup-v1.c
View File

@ -471,6 +471,7 @@ static void *cgroup_pidlist_next(struct seq_file *s, void *v, loff_t *pos)
*/
p++;
if (p >= end) {
(*pos)++;
return NULL;
} else {
*pos = *p;
@ -782,7 +783,7 @@ void cgroup1_release_agent(struct work_struct *work)
pathbuf = kmalloc(PATH_MAX, GFP_KERNEL);
agentbuf = kstrdup(cgrp->root->release_agent_path, GFP_KERNEL);
if (!pathbuf || !agentbuf)
if (!pathbuf || !agentbuf || !strlen(agentbuf))
goto out;
spin_lock_irq(&css_set_lock);

39
kernel/cgroup/cgroup.c
View File

@ -3542,21 +3542,21 @@ static int cpu_stat_show(struct seq_file *seq, void *v)
static int cgroup_io_pressure_show(struct seq_file *seq, void *v)
{
struct cgroup *cgrp = seq_css(seq)->cgroup;
struct psi_group *psi = cgroup_id(cgrp) == 1 ? &psi_system : &cgrp->psi;
struct psi_group *psi = cgroup_ino(cgrp) == 1 ? &psi_system : &cgrp->psi;
return psi_show(seq, psi, PSI_IO);
}
static int cgroup_memory_pressure_show(struct seq_file *seq, void *v)
{
struct cgroup *cgrp = seq_css(seq)->cgroup;
struct psi_group *psi = cgroup_id(cgrp) == 1 ? &psi_system : &cgrp->psi;
struct psi_group *psi = cgroup_ino(cgrp) == 1 ? &psi_system : &cgrp->psi;
return psi_show(seq, psi, PSI_MEM);
}
static int cgroup_cpu_pressure_show(struct seq_file *seq, void *v)
{
struct cgroup *cgrp = seq_css(seq)->cgroup;
struct psi_group *psi = cgroup_id(cgrp) == 1 ? &psi_system : &cgrp->psi;
struct psi_group *psi = cgroup_ino(cgrp) == 1 ? &psi_system : &cgrp->psi;
return psi_show(seq, psi, PSI_CPU);
}
@ -4400,12 +4400,16 @@ static void css_task_iter_advance_css_set(struct css_task_iter *it)
}
} while (!css_set_populated(cset) && list_empty(&cset->dying_tasks));
if (!list_empty(&cset->tasks))
if (!list_empty(&cset->tasks)) {
it->task_pos = cset->tasks.next;
else if (!list_empty(&cset->mg_tasks))
it->cur_tasks_head = &cset->tasks;
} else if (!list_empty(&cset->mg_tasks)) {
it->task_pos = cset->mg_tasks.next;
else
it->cur_tasks_head = &cset->mg_tasks;
} else {
it->task_pos = cset->dying_tasks.next;
it->cur_tasks_head = &cset->dying_tasks;
}
it->tasks_head = &cset->tasks;
it->mg_tasks_head = &cset->mg_tasks;
@ -4463,10 +4467,14 @@ static void css_task_iter_advance(struct css_task_iter *it)
else
it->task_pos = it->task_pos->next;
if (it->task_pos == it->tasks_head)
if (it->task_pos == it->tasks_head) {
it->task_pos = it->mg_tasks_head->next;
if (it->task_pos == it->mg_tasks_head)
it->cur_tasks_head = it->mg_tasks_head;
}
if (it->task_pos == it->mg_tasks_head) {
it->task_pos = it->dying_tasks_head->next;
it->cur_tasks_head = it->dying_tasks_head;
}
if (it->task_pos == it->dying_tasks_head)
css_task_iter_advance_css_set(it);
} else {
@ -4485,11 +4493,12 @@ static void css_task_iter_advance(struct css_task_iter *it)
goto repeat;
/* and dying leaders w/o live member threads */
if (!atomic_read(&task->signal->live))
if (it->cur_tasks_head == it->dying_tasks_head &&
!atomic_read(&task->signal->live))
goto repeat;
} else {
/* skip all dying ones */
if (task->flags & PF_EXITING)
if (it->cur_tasks_head == it->dying_tasks_head)
goto repeat;
}
}
@ -4595,6 +4604,9 @@ static void *cgroup_procs_next(struct seq_file *s, void *v, loff_t *pos)
struct kernfs_open_file *of = s->private;
struct css_task_iter *it = of->priv;
if (pos)
(*pos)++;
return css_task_iter_next(it);
}
@ -4610,7 +4622,7 @@ static void *__cgroup_procs_start(struct seq_file *s, loff_t *pos,
* from position 0, so we can simply keep iterating on !0 *pos.
*/
if (!it) {
if (WARN_ON_ONCE((*pos)++))
if (WARN_ON_ONCE((*pos)))
return ERR_PTR(-EINVAL);
it = kzalloc(sizeof(*it), GFP_KERNEL);
@ -4618,10 +4630,11 @@ static void *__cgroup_procs_start(struct seq_file *s, loff_t *pos,
return ERR_PTR(-ENOMEM);
of->priv = it;
css_task_iter_start(&cgrp->self, iter_flags, it);
} else if (!(*pos)++) {
} else if (!(*pos)) {
css_task_iter_end(it);
css_task_iter_start(&cgrp->self, iter_flags, it);
}
} else
return it->cur_task;
return cgroup_procs_next(s, NULL, NULL);
}