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Commit 7ccb9743 authored by Li Zefan's avatar Li Zefan Committed by Linus Torvalds
Browse files

freezer_cg: fix improper BUG_ON() causing oops 



The BUG_ON() should be protected by freezer->lock, otherwise it can be
triggered easily when a task has been unfreezed but the corresponding
cgroup hasn't been changed to FROZEN state.

Signed-off-by: default avatarLi Zefan <lizf@cn.fujitsu.com>
Acked-by: default avatarCedric Le Goater <clg@fr.ibm.com>
Acked-by: default avatarMatt Helsley <matthltc@us.ibm.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent df8bc08c

kernel/cgroup_freezer.c

+2 −1
Original line number Diff line number Diff line
@@ -190,8 +190,9 @@ static void freezer_fork(struct cgroup_subsys *ss, struct task_struct *task) 
	freezer = task_freezer(task);

	task_unlock(task);



	BUG_ON(freezer->state == CGROUP_FROZEN);

	spin_lock_irq(&freezer->lock);

	BUG_ON(freezer->state == CGROUP_FROZEN);



	/* Locking avoids race with FREEZING -> THAWED transitions. */

	if (freezer->state == CGROUP_FREEZING)

		freeze_task(task, true);