From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: linux-kernel@vger.kernel.org
Cc: mingo@kernel.org, laijs@cn.fujitsu.com, dipankar@in.ibm.com,
akpm@linux-foundation.org, mathieu.desnoyers@efficios.com,
josh@joshtriplett.org, niv@us.ibm.com, tglx@linutronix.de,
peterz@infradead.org, rostedt@goodmis.org, dhowells@redhat.com,
edumazet@google.com, darren@dvhart.com, fweisbec@gmail.com,
sbw@mit.edu, "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
Stephen Hemminger <stephen@networkplumber.org>,
"David S. Miller" <davem@davemloft.net>,
bridge@lists.linux-foundation.org, netdev@vger.kernel.org
Subject: [PATCH tip/core/rcu 04/13] wireless: Apply rcu_access_pointer() to avoid sparse false positive
Date: Tue, 24 Sep 2013 18:35:07 -0700 [thread overview]
Message-ID: <1380072916-31557-4-git-send-email-paulmck@linux.vnet.ibm.com> (raw)
In-Reply-To: <1380072916-31557-1-git-send-email-paulmck@linux.vnet.ibm.com>
From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
The sparse checking for rcu_assign_pointer() was recently upgraded
to reject non-__kernel address spaces. This also rejects __rcu,
which is almost always the right thing to do. However, the uses in
cfg80211_combine_bsses() and cfg80211_bss_update() are legitimate:
They is assigning a pointer to an element from an RCU-protected list,
and all elements of this list are already visible to caller.
This commit therefore silences these false positives by laundering the
pointers using rcu_access_pointer() as suggested by Josh Triplett.
Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Stephen Hemminger <stephen@networkplumber.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: bridge@lists.linux-foundation.org
Cc: netdev@vger.kernel.org
---
net/wireless/scan.c | 14 +++++++-------
1 file changed, 7 insertions(+), 7 deletions(-)
diff --git a/net/wireless/scan.c b/net/wireless/scan.c
index eeb7148..edde117 100644
--- a/net/wireless/scan.c
+++ b/net/wireless/scan.c
@@ -671,7 +671,7 @@ static bool cfg80211_combine_bsses(struct cfg80211_registered_device *dev,
bss->pub.hidden_beacon_bss = &new->pub;
new->refcount += bss->refcount;
rcu_assign_pointer(bss->pub.beacon_ies,
- new->pub.beacon_ies);
+ rcu_access_pointer(new->pub.beacon_ies));
}
return true;
@@ -706,10 +706,10 @@ cfg80211_bss_update(struct cfg80211_registered_device *dev,
old = rcu_access_pointer(found->pub.proberesp_ies);
rcu_assign_pointer(found->pub.proberesp_ies,
- tmp->pub.proberesp_ies);
+ rcu_access_pointer(tmp->pub.proberesp_ies));
/* Override possible earlier Beacon frame IEs */
rcu_assign_pointer(found->pub.ies,
- tmp->pub.proberesp_ies);
+ rcu_access_pointer(tmp->pub.proberesp_ies));
if (old)
kfree_rcu((struct cfg80211_bss_ies *)old,
rcu_head);
@@ -740,12 +740,12 @@ cfg80211_bss_update(struct cfg80211_registered_device *dev,
old = rcu_access_pointer(found->pub.beacon_ies);
rcu_assign_pointer(found->pub.beacon_ies,
- tmp->pub.beacon_ies);
+ rcu_access_pointer(tmp->pub.beacon_ies));
/* Override IEs if they were from a beacon before */
if (old == rcu_access_pointer(found->pub.ies))
rcu_assign_pointer(found->pub.ies,
- tmp->pub.beacon_ies);
+ rcu_access_pointer(tmp->pub.beacon_ies));
/* Assign beacon IEs to all sub entries */
list_for_each_entry(bss, &found->hidden_list,
@@ -756,7 +756,7 @@ cfg80211_bss_update(struct cfg80211_registered_device *dev,
WARN_ON(ies != old);
rcu_assign_pointer(bss->pub.beacon_ies,
- tmp->pub.beacon_ies);
+ rcu_access_pointer(tmp->pub.beacon_ies));
}
if (old)
@@ -804,7 +804,7 @@ cfg80211_bss_update(struct cfg80211_registered_device *dev,
&hidden->hidden_list);
hidden->refcount++;
rcu_assign_pointer(new->pub.beacon_ies,
- hidden->pub.beacon_ies);
+ rcu_access_pointer(hidden->pub.beacon_ies));
}
} else {
/*
--
1.8.1.5
next prev parent reply other threads:[~2013-09-25 1:39 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-25 1:34 [PATCH tip/core/rcu 0/13] Sparse-related updates for 3.13 Paul E. McKenney
2013-09-25 1:35 ` [PATCH tip/core/rcu 01/13] rcu: Make rcu_assign_pointer's assignment volatile and type-safe Paul E. McKenney
2013-09-25 1:35 ` [PATCH tip/core/rcu 02/13] notifiers: Apply rcu_access_pointer() to avoid sparse false positive Paul E. McKenney
2013-09-25 1:35 ` [PATCH tip/core/rcu 03/13] bridge: " Paul E. McKenney
2013-09-25 1:35 ` Paul E. McKenney [this message]
2013-09-25 17:48 ` [PATCH tip/core/rcu 04/13] wireless: " Ben Hutchings
2013-09-25 18:26 ` Paul E. McKenney
2013-09-25 1:35 ` [PATCH tip/core/rcu 05/13] decnet: " Paul E. McKenney
2013-09-25 1:35 ` [PATCH tip/core/rcu 06/13] ipv4/ip_socketglue: " Paul E. McKenney
2013-09-25 1:35 ` [PATCH tip/core/rcu 07/13] ipv6/ip6_tunnel: " Paul E. McKenney
2013-09-25 1:35 ` [PATCH tip/core/rcu 08/13] ipv6/ip6_gre: " Paul E. McKenney
2013-09-25 1:35 ` [PATCH tip/core/rcu 09/13] ipv6/sit: " Paul E. McKenney
2013-09-25 1:35 ` [PATCH tip/core/rcu 10/13] mac80211: " Paul E. McKenney
2013-09-25 1:35 ` [PATCH tip/core/rcu 11/13] bridge/br_mdb: " Paul E. McKenney
2013-09-25 1:35 ` [PATCH tip/core/rcu 12/13] bonding/bond_main: " Paul E. McKenney
2013-09-25 1:35 ` [PATCH tip/core/rcu 13/13] bonding/bond_alb.c: " Paul E. McKenney
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