Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756395Ab0DWTpA (ORCPT ); Fri, 23 Apr 2010 15:45:00 -0400 Received: from e1.ny.us.ibm.com ([32.97.182.141]:38903 "EHLO e1.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756028Ab0DWTng (ORCPT ); Fri, 23 Apr 2010 15:43:36 -0400 From: "Paul E. McKenney" To: linux-kernel@vger.kernel.org Cc: mingo@elte.hu, laijs@cn.fujitsu.com, dipankar@in.ibm.com, akpm@linux-foundation.org, mathieu.desnoyers@polymtl.ca, josh@joshtriplett.org, dvhltc@us.ibm.com, niv@us.ibm.com, tglx@linutronix.de, peterz@infradead.org, rostedt@goodmis.org, Valdis.Kletnieks@vt.edu, dhowells@redhat.com, eric.dumazet@gmail.com, "Paul E. McKenney" Subject: [PATCH v2.6.34-rc5 07/12] KEYS: Fix an RCU warning in the reading of user keys Date: Fri, 23 Apr 2010 12:43:25 -0700 Message-Id: <1272051810-11249-7-git-send-email-paulmck@linux.vnet.ibm.com> X-Mailer: git-send-email 1.7.0 In-Reply-To: <20100423194255.GE2589@linux.vnet.ibm.com> References: <20100423194255.GE2589@linux.vnet.ibm.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1861 Lines: 52 From: David Howells Fix an RCU warning in the reading of user keys: =================================================== [ INFO: suspicious rcu_dereference_check() usage. ] --------------------------------------------------- security/keys/user_defined.c:202 invoked rcu_dereference_check() without protection! other info that might help us debug this: rcu_scheduler_active = 1, debug_locks = 0 1 lock held by keyctl/3637: #0: (&key->sem){+++++.}, at: [] keyctl_read_key+0x9c/0xcf stack backtrace: Pid: 3637, comm: keyctl Not tainted 2.6.34-rc5-cachefs #18 Call Trace: [] lockdep_rcu_dereference+0xaa/0xb2 [] user_read+0x47/0x91 [] keyctl_read_key+0xac/0xcf [] sys_keyctl+0x75/0xb7 [] system_call_fastpath+0x16/0x1b Signed-off-by: David Howells Signed-off-by: Paul E. McKenney --- security/keys/user_defined.c | 3 ++- 1 files changed, 2 insertions(+), 1 deletions(-) diff --git a/security/keys/user_defined.c b/security/keys/user_defined.c index 7c687d5..e9aa079 100644 --- a/security/keys/user_defined.c +++ b/security/keys/user_defined.c @@ -199,7 +199,8 @@ long user_read(const struct key *key, char __user *buffer, size_t buflen) struct user_key_payload *upayload; long ret; - upayload = rcu_dereference(key->payload.data); + upayload = rcu_dereference_protected( + key->payload.data, rwsem_is_locked(&((struct key *)key)->sem)); ret = upayload->datalen; /* we can return the data as is */ -- 1.7.0 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/