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device_cgroup: don't grab mutex in rcu callback

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Commit 103a197c0c ("security/device_cgroup: lock assert fails in
dev_exception_clean()") grabs devcgroup_mutex to fix assert failure, but
a mutex can't be grabbed in rcu callback.  Since there shouldn't be any
other references when css_free is called, mutex isn't needed for list
cleanup in devcgroup_css_free().

Signed-off-by: Jerry Snitselaar <jerry.snitselaar@oracle.com>
Acked-by: Tejun Heo <tj@kernel.org>
Acked-by: Aristeu Rozanski <aris@redhat.com>
Cc: James Morris <james.l.morris@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Jerry Snitselaar 2013-02-21 16:41:31 -08:00 committed by Linus Torvalds
parent 024e4ec185
commit 53eb8c82d5
1 changed files with 12 additions and 9 deletions
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21
security/device_cgroup.c
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@ -159,6 +159,16 @@ static void dev_exception_rm(struct dev_cgroup *dev_cgroup,
}
}
static void __dev_exception_clean(struct dev_cgroup *dev_cgroup)
{
struct dev_exception_item *ex, *tmp;
list_for_each_entry_safe(ex, tmp, &dev_cgroup->exceptions, list) {
list_del_rcu(&ex->list);
kfree_rcu(ex, rcu);
}
}
/**
* dev_exception_clean - frees all entries of the exception list
* @dev_cgroup: dev_cgroup with the exception list to be cleaned
@ -167,14 +177,9 @@ static void dev_exception_rm(struct dev_cgroup *dev_cgroup,
*/
static void dev_exception_clean(struct dev_cgroup *dev_cgroup)
{
struct dev_exception_item *ex, *tmp;
lockdep_assert_held(&devcgroup_mutex);
list_for_each_entry_safe(ex, tmp, &dev_cgroup->exceptions, list) {
list_del_rcu(&ex->list);
kfree_rcu(ex, rcu);
}
__dev_exception_clean(dev_cgroup);
}
/*
@ -215,9 +220,7 @@ static void devcgroup_css_free(struct cgroup *cgroup)
struct dev_cgroup *dev_cgroup;
dev_cgroup = cgroup_to_devcgroup(cgroup);
mutex_lock(&devcgroup_mutex);
dev_exception_clean(dev_cgroup);
mutex_unlock(&devcgroup_mutex);
__dev_exception_clean(dev_cgroup);
kfree(dev_cgroup);
}