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cgroup: fix spurious lockdep warning in cgroup_exit()

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cgroup_exit() is called in fork and exit path. If it's called in the
failure path during fork, PF_EXITING isn't set, and then lockdep will
complain.

Fix this by removing cgroup_exit() in that failure path. cgroup_fork()
does nothing that needs cleanup.

Reported-by: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
This commit is contained in:
Li Zefan 2014-03-28 15:18:27 +08:00 • committed by Tejun Heo
parent 01a9714061
commit e8604cb436
2 changed files with 3 additions and 5 deletions
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3
kernel/cgroup.c
View file

@ -4431,8 +4431,7 @@ void cgroup_post_fork(struct task_struct *child)
* notify_on_release(), then leave the task attached to the root cgroup in * notify_on_release(), then leave the task attached to the root cgroup in
* each hierarchy for the remainder of its exit. No need to bother with * each hierarchy for the remainder of its exit. No need to bother with
* init_css_set refcnting. init_css_set never goes away and we can't race * init_css_set refcnting. init_css_set never goes away and we can't race
* with migration path - either PF_EXITING is visible to migration path or * with migration path - PF_EXITING is visible to migration path.
* @tsk never got on the tasklist.
*/ */
void cgroup_exit(struct task_struct *tsk, int run_callbacks) void cgroup_exit(struct task_struct *tsk, int run_callbacks)
{ {

5
kernel/fork.c
View file

@ -1271,7 +1271,7 @@ static struct task_struct *copy_process(unsigned long clone_flags,
if (IS_ERR(p->mempolicy)) { if (IS_ERR(p->mempolicy)) {
retval = PTR_ERR(p->mempolicy); retval = PTR_ERR(p->mempolicy);
p->mempolicy = NULL; p->mempolicy = NULL;
goto bad_fork_cleanup_cgroup; goto bad_fork_cleanup_threadgroup_lock;
} }
mpol_fix_fork_child_flag(p); mpol_fix_fork_child_flag(p);
#endif #endif
@ -1524,11 +1524,10 @@ bad_fork_cleanup_policy:
perf_event_free_task(p); perf_event_free_task(p);
#ifdef CONFIG_NUMA #ifdef CONFIG_NUMA
mpol_put(p->mempolicy); mpol_put(p->mempolicy);
bad_fork_cleanup_cgroup: bad_fork_cleanup_threadgroup_lock:
#endif #endif
if (clone_flags & CLONE_THREAD) if (clone_flags & CLONE_THREAD)
threadgroup_change_end(current); threadgroup_change_end(current);
cgroup_exit(p, 0);
delayacct_tsk_free(p); delayacct_tsk_free(p);
module_put(task_thread_info(p)->exec_domain->module); module_put(task_thread_info(p)->exec_domain->module);
bad_fork_cleanup_count: bad_fork_cleanup_count: