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Message-Id: <1399126367-27827-1-git-send-email-bjorn@mork.no>
Date: Sat, 3 May 2014 16:12:47 +0200
From: Bjørn Mork <bjorn@...k.no>
To: netdev@...r.kernel.org
Cc: linux-usb@...r.kernel.org, Eric Dumazet <eric.dumazet@...il.com>,
Greg Suarez <gsuarez@...thmicro.com>,
Oliver Neukum <oliver@...kum.org>,
Bjørn Mork <bjorn@...k.no>
Subject: [PATCH net,stable v2] net: cdc_mbim: __vlan_find_dev_deep need rcu_read_lock
Fixes this warning introduced by commit 5b8f15f78e6f
("net: cdc_mbim: handle IPv6 Neigbor Solicitations"):
===============================
[ INFO: suspicious RCU usage. ]
3.15.0-rc3 #213 Tainted: G W O
-------------------------------
net/8021q/vlan_core.c:69 suspicious rcu_dereference_check() usage!
other info that might help us debug this:
rcu_scheduler_active = 1, debug_locks = 1
no locks held by ksoftirqd/0/3.
stack backtrace:
CPU: 0 PID: 3 Comm: ksoftirqd/0 Tainted: G W O 3.15.0-rc3 #213
Hardware name: LENOVO 2776LEG/2776LEG, BIOS 6EET55WW (3.15 ) 12/19/2011
0000000000000001 ffff880232533bf0 ffffffff813a5ee6 0000000000000006
ffff880232530090 ffff880232533c20 ffffffff81076b94 0000000000000081
0000000000000000 ffff8802085ac000 ffff88007fc8ea00 ffff880232533c50
Call Trace:
[<ffffffff813a5ee6>] dump_stack+0x4e/0x68
[<ffffffff81076b94>] lockdep_rcu_suspicious+0xfa/0x103
[<ffffffff813978a6>] __vlan_find_dev_deep+0x54/0x94
[<ffffffffa04a1938>] cdc_mbim_rx_fixup+0x379/0x66a [cdc_mbim]
[<ffffffff813ab76f>] ? _raw_spin_unlock_irqrestore+0x3a/0x49
[<ffffffff81079671>] ? trace_hardirqs_on_caller+0x192/0x1a1
[<ffffffffa059bd10>] usbnet_bh+0x59/0x287 [usbnet]
[<ffffffff8104067d>] tasklet_action+0xbb/0xcd
[<ffffffff81040057>] __do_softirq+0x14c/0x30d
[<ffffffff81040237>] run_ksoftirqd+0x1f/0x50
[<ffffffff8105f13e>] smpboot_thread_fn+0x172/0x18e
[<ffffffff8105efcc>] ? SyS_setgroups+0xdf/0xdf
[<ffffffff810594b0>] kthread+0xb5/0xbd
[<ffffffff813a84b1>] ? __wait_for_common+0x13b/0x170
[<ffffffff810593fb>] ? __kthread_parkme+0x5c/0x5c
[<ffffffff813b147c>] ret_from_fork+0x7c/0xb0
[<ffffffff810593fb>] ? __kthread_parkme+0x5c/0x5c
Fixes: 5b8f15f78e6f ("net: cdc_mbim: handle IPv6 Neigbor Solicitations")
Signed-off-by: Bjørn Mork <bjorn@...k.no>
---
v2: get a ref to the netdev before releasing the lock. Thanks to Eric Dumazet
Please add this to the stable v3.13 and v3.14 queues as well. Thanks.
drivers/net/usb/cdc_mbim.c | 18 +++++++++++++-----
1 file changed, 13 insertions(+), 5 deletions(-)
diff --git a/drivers/net/usb/cdc_mbim.c b/drivers/net/usb/cdc_mbim.c
index c9f3281506af..13f7705fd679 100644
--- a/drivers/net/usb/cdc_mbim.c
+++ b/drivers/net/usb/cdc_mbim.c
@@ -204,17 +204,23 @@ static void do_neigh_solicit(struct usbnet *dev, u8 *buf, u16 tci)
return;
/* need to send the NA on the VLAN dev, if any */
- if (tci)
+ rcu_read_lock();
+ if (tci) {
netdev = __vlan_find_dev_deep(dev->net, htons(ETH_P_8021Q),
tci);
- else
+ if (!netdev) {
+ rcu_read_unlock();
+ return;
+ }
+ } else {
netdev = dev->net;
- if (!netdev)
- return;
+ }
+ dev_hold(netdev);
+ rcu_read_unlock();
in6_dev = in6_dev_get(netdev);
if (!in6_dev)
- return;
+ goto out;
is_router = !!in6_dev->cnf.forwarding;
in6_dev_put(in6_dev);
@@ -224,6 +230,8 @@ static void do_neigh_solicit(struct usbnet *dev, u8 *buf, u16 tci)
true /* solicited */,
false /* override */,
true /* inc_opt */);
+out:
+ dev_put(netdev);
}
static bool is_neigh_solicit(u8 *buf, size_t len)
--
2.0.0.rc0
--
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