From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
stable@vger.kernel.org, John Sperbeck <jsperbeck@google.com>,
Eric Dumazet <edumazet@google.com>,
Jesper Dangaard Brouer <brouer@redhat.com>,
"David S. Miller" <davem@davemloft.net>
Subject: [PATCH 4.4 17/34] net: pktgen: remove rcu locking in pktgen_change_name()
Date: Sun, 13 Nov 2016 12:24:49 +0100 [thread overview]
Message-ID: <20161113112400.826080973@linuxfoundation.org> (raw)
In-Reply-To: <20161113112400.008903838@linuxfoundation.org>
4.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Eric Dumazet <edumazet@google.com>
[ Upstream commit 9a0b1e8ba4061778897b544afc898de2163382f7 ]
After Jesper commit back in linux-3.18, we trigger a lockdep
splat in proc_create_data() while allocating memory from
pktgen_change_name().
This patch converts t->if_lock to a mutex, since it is now only
used from control path, and adds proper locking to pktgen_change_name()
1) pktgen_thread_lock to protect the outer loop (iterating threads)
2) t->if_lock to protect the inner loop (iterating devices)
Note that before Jesper patch, pktgen_change_name() was lacking proper
protection, but lockdep was not able to detect the problem.
Fixes: 8788370a1d4b ("pktgen: RCU-ify "if_list" to remove lock in next_to_run()")
Reported-by: John Sperbeck <jsperbeck@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/core/pktgen.c | 17 ++++++++++-------
1 file changed, 10 insertions(+), 7 deletions(-)
--- a/net/core/pktgen.c
+++ b/net/core/pktgen.c
@@ -215,8 +215,8 @@
#define M_NETIF_RECEIVE 1 /* Inject packets into stack */
/* If lock -- protects updating of if_list */
-#define if_lock(t) spin_lock(&(t->if_lock));
-#define if_unlock(t) spin_unlock(&(t->if_lock));
+#define if_lock(t) mutex_lock(&(t->if_lock));
+#define if_unlock(t) mutex_unlock(&(t->if_lock));
/* Used to help with determining the pkts on receive */
#define PKTGEN_MAGIC 0xbe9be955
@@ -422,7 +422,7 @@ struct pktgen_net {
};
struct pktgen_thread {
- spinlock_t if_lock; /* for list of devices */
+ struct mutex if_lock; /* for list of devices */
struct list_head if_list; /* All device here */
struct list_head th_list;
struct task_struct *tsk;
@@ -2002,11 +2002,13 @@ static void pktgen_change_name(const str
{
struct pktgen_thread *t;
+ mutex_lock(&pktgen_thread_lock);
+
list_for_each_entry(t, &pn->pktgen_threads, th_list) {
struct pktgen_dev *pkt_dev;
- rcu_read_lock();
- list_for_each_entry_rcu(pkt_dev, &t->if_list, list) {
+ if_lock(t);
+ list_for_each_entry(pkt_dev, &t->if_list, list) {
if (pkt_dev->odev != dev)
continue;
@@ -2021,8 +2023,9 @@ static void pktgen_change_name(const str
dev->name);
break;
}
- rcu_read_unlock();
+ if_unlock(t);
}
+ mutex_unlock(&pktgen_thread_lock);
}
static int pktgen_device_event(struct notifier_block *unused,
@@ -3726,7 +3729,7 @@ static int __net_init pktgen_create_thre
return -ENOMEM;
}
- spin_lock_init(&t->if_lock);
+ mutex_init(&t->if_lock);
t->cpu = cpu;
INIT_LIST_HEAD(&t->if_list);
next prev parent reply other threads:[~2016-11-13 11:36 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CGME20161113112504epcas1p23b8af4aabfbd40c07be5d48fcfd80e44@epcas1p2.samsung.com>
2016-11-13 11:24 ` [PATCH 4.4 00/34] 4.4.32-stable review Greg Kroah-Hartman
2016-11-13 11:24 ` [PATCH 4.4 01/34] tcp: fix overflow in __tcp_retransmit_skb() Greg Kroah-Hartman
2016-11-13 11:24 ` [PATCH 4.4 02/34] net: avoid sk_forward_alloc overflows Greg Kroah-Hartman
2016-11-13 11:24 ` [PATCH 4.4 03/34] tcp: fix wrong checksum calculation on MTU probing Greg Kroah-Hartman
2016-11-13 11:24 ` [PATCH 4.4 04/34] tcp: fix a compile error in DBGUNDO() Greg Kroah-Hartman
2016-11-13 11:24 ` [PATCH 4.4 05/34] ip6_gre: fix flowi6_proto value in ip6gre_xmit_other() Greg Kroah-Hartman
2016-11-13 11:24 ` [PATCH 4.4 06/34] ipmr, ip6mr: fix scheduling while atomic and a deadlock with ipmr_get_route Greg Kroah-Hartman
2016-11-13 11:24 ` [PATCH 4.4 07/34] tg3: Avoid NULL pointer dereference in tg3_io_error_detected() Greg Kroah-Hartman
2016-11-13 11:24 ` [PATCH 4.4 09/34] net: pktgen: fix pkt_size Greg Kroah-Hartman
2016-11-13 11:24 ` [PATCH 4.4 10/34] net/sched: act_vlan: Push skb->data to mac_header prior calling skb_vlan_*() functions Greg Kroah-Hartman
2016-11-14 7:07 ` Shmulik Ladkani
2016-11-13 11:24 ` [PATCH 4.4 11/34] net: Add netdev all_adj_list refcnt propagation to fix panic Greg Kroah-Hartman
2016-11-13 11:24 ` [PATCH 4.4 12/34] packet: call fanout_release, while UNREGISTERING a netdev Greg Kroah-Hartman
2016-11-13 11:24 ` [PATCH 4.4 13/34] netlink: do not enter direct reclaim from netlink_dump() Greg Kroah-Hartman
2016-11-13 11:24 ` [PATCH 4.4 14/34] ipv6: tcp: restore IP6CB for pktoptions skbs Greg Kroah-Hartman
2016-11-13 11:24 ` [PATCH 4.4 15/34] ip6_tunnel: fix ip6_tnl_lookup Greg Kroah-Hartman
2016-11-13 11:24 ` [PATCH 4.4 16/34] ipv6: correctly add local routes when lo goes up Greg Kroah-Hartman
2016-11-13 11:24 ` Greg Kroah-Hartman [this message]
2016-11-13 11:24 ` [PATCH 4.4 18/34] bridge: multicast: restore perm router ports on multicast enable Greg Kroah-Hartman
2016-11-13 11:24 ` [PATCH 4.4 19/34] rtnetlink: Add rtnexthop offload flag to compare mask Greg Kroah-Hartman
2016-11-13 11:24 ` [PATCH 4.4 21/34] ipv4: disable BH in set_ping_group_range() Greg Kroah-Hartman
2016-11-13 11:24 ` [PATCH 4.4 22/34] ipv4: use the right lock for ping_group_range Greg Kroah-Hartman
2016-11-13 11:24 ` [PATCH 4.4 23/34] net: sctp, forbid negative length Greg Kroah-Hartman
2016-11-13 11:24 ` [PATCH 4.4 24/34] udp: fix IP_CHECKSUM handling Greg Kroah-Hartman
2016-11-13 11:24 ` [PATCH 4.4 25/34] net sched filters: fix notification of filter delete with proper handle Greg Kroah-Hartman
2016-11-13 11:24 ` [PATCH 4.4 26/34] sctp: validate chunk len before actually using it Greg Kroah-Hartman
2016-11-13 11:24 ` [PATCH 4.4 27/34] packet: on direct_xmit, limit tso and csum to supported devices Greg Kroah-Hartman
2016-11-13 11:25 ` [PATCH 4.4 32/34] drm/amdgpu: fix DP mode validation Greg Kroah-Hartman
2016-11-13 11:25 ` [PATCH 4.4 34/34] drm/radeon: " Greg Kroah-Hartman
2016-11-13 20:41 ` [PATCH 4.4 00/34] 4.4.32-stable review Guenter Roeck
[not found] ` <5828d40c.212dc20a.9adc7.8f2f@mx.google.com>
2016-11-14 7:53 ` Greg Kroah-Hartman
2016-11-14 16:47 ` Shuah Khan
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