From: Amol Grover <frextrite@gmail.com>
To: James Morris <jmorris@namei.org>, "Serge E . Hallyn" <serge@hallyn.com>
Cc: linux-kernel@vger.kernel.org,
linux-kernel-mentees@lists.linuxfoundation.org,
Joel Fernandes <joel@joelfernandes.org>,
Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>,
"Paul E . McKenney" <paulmck@kernel.org>,
linux-security-module@vger.kernel.org,
Amol Grover <frextrite@gmail.com>
Subject: [PATCH RESEND] device_cgroup: Fix RCU list debugging warning
Date: Mon, 6 Apr 2020 16:29:50 +0530 [thread overview]
Message-ID: <20200406105950.GA2285@workstation-kernel-dev> (raw)
exceptions may be traversed using list_for_each_entry_rcu()
outside of an RCU read side critical section BUT under the
protection of decgroup_mutex. Hence add the corresponding
lockdep expression to fix the following false-positive
warning:
[ 2.304417] =============================
[ 2.304418] WARNING: suspicious RCU usage
[ 2.304420] 5.5.4-stable #17 Tainted: G E
[ 2.304422] -----------------------------
[ 2.304424] security/device_cgroup.c:355 RCU-list traversed in non-reader section!!
Signed-off-by: Amol Grover <frextrite@gmail.com>
---
security/device_cgroup.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/security/device_cgroup.c b/security/device_cgroup.c
index 7d0f8f7431ff..b7da9e0970d9 100644
--- a/security/device_cgroup.c
+++ b/security/device_cgroup.c
@@ -352,7 +352,8 @@ static bool match_exception_partial(struct list_head *exceptions, short type,
{
struct dev_exception_item *ex;
- list_for_each_entry_rcu(ex, exceptions, list) {
+ list_for_each_entry_rcu(ex, exceptions, list,
+ lockdep_is_held(&devcgroup_mutex)) {
if ((type & DEVCG_DEV_BLOCK) && !(ex->type & DEVCG_DEV_BLOCK))
continue;
if ((type & DEVCG_DEV_CHAR) && !(ex->type & DEVCG_DEV_CHAR))
--
2.24.1
next reply other threads:[~2020-04-06 11:00 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-06 10:59 Amol Grover [this message]
2020-06-06 20:23 ` [PATCH RESEND] device_cgroup: Fix RCU list debugging warning Stephen Rothwell
2020-06-07 19:08 ` Paul E. McKenney
2020-06-08 4:17 ` Serge E. Hallyn
2020-08-17 2:07 ` Stephen Rothwell
2020-08-20 18:28 ` James Morris
2020-08-20 22:38 ` Stephen Rothwell
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