From 53eb8c82d581fdd4b389a3e417261f3ae924e603 Mon Sep 17 00:00:00 2001 From: Jerry Snitselaar Date: Thu, 21 Feb 2013 16:41:31 -0800 Subject: [PATCH] device_cgroup: don't grab mutex in rcu callback Commit 103a197c0c4e ("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 Acked-by: Tejun Heo Acked-by: Aristeu Rozanski Cc: James Morris Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- security/device_cgroup.c | 21 ++++++++++++--------- 1 file changed, 12 insertions(+), 9 deletions(-) diff --git a/security/device_cgroup.c b/security/device_cgroup.c index d794abcc4b3b..1c69e38e3a2c 100644 --- a/security/device_cgroup.c +++ b/security/device_cgroup.c @@ -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); } -- 2.39.5