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authorsubashab@codeaurora.org <subashab@codeaurora.org>2016-02-02 05:11:10 +0300
committerDavid S. Miller <davem@davemloft.net>2016-02-06 11:08:15 +0300
commit16186a82de1fdd868255448274e64ae2616e2640 (patch)
tree1865e640d8e7b5399b8951eba2b03b43d2365547 /net
parent34229b277480f46c1e9a19f027f30b074512e68b (diff)
downloadlinux-16186a82de1fdd868255448274e64ae2616e2640.tar.xz
ipv6: addrconf: Fix recursive spin lock call
A rcu stall with the following backtrace was seen on a system with forwarding, optimistic_dad and use_optimistic set. To reproduce, set these flags and allow ipv6 autoconf. This occurs because the device write_lock is acquired while already holding the read_lock. Back trace below - INFO: rcu_preempt self-detected stall on CPU { 1} (t=2100 jiffies g=3992 c=3991 q=4471) <6> Task dump for CPU 1: <2> kworker/1:0 R running task 12168 15 2 0x00000002 <2> Workqueue: ipv6_addrconf addrconf_dad_work <6> Call trace: <2> [<ffffffc000084da8>] el1_irq+0x68/0xdc <2> [<ffffffc000cc4e0c>] _raw_write_lock_bh+0x20/0x30 <2> [<ffffffc000bc5dd8>] __ipv6_dev_ac_inc+0x64/0x1b4 <2> [<ffffffc000bcbd2c>] addrconf_join_anycast+0x9c/0xc4 <2> [<ffffffc000bcf9f0>] __ipv6_ifa_notify+0x160/0x29c <2> [<ffffffc000bcfb7c>] ipv6_ifa_notify+0x50/0x70 <2> [<ffffffc000bd035c>] addrconf_dad_work+0x314/0x334 <2> [<ffffffc0000b64c8>] process_one_work+0x244/0x3fc <2> [<ffffffc0000b7324>] worker_thread+0x2f8/0x418 <2> [<ffffffc0000bb40c>] kthread+0xe0/0xec v2: do addrconf_dad_kick inside read lock and then acquire write lock for ipv6_ifa_notify as suggested by Eric Fixes: 7fd2561e4ebdd ("net: ipv6: Add a sysctl to make optimistic addresses useful candidates") Cc: Eric Dumazet <edumazet@google.com> Cc: Erik Kline <ek@google.com> Cc: Hannes Frederic Sowa <hannes@stressinduktion.org> Signed-off-by: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org> Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r--net/ipv6/addrconf.c5
1 files changed, 4 insertions, 1 deletions
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 38eeddedfc21..9efd9ffdc34c 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -3538,6 +3538,7 @@ static void addrconf_dad_begin(struct inet6_ifaddr *ifp)
{
struct inet6_dev *idev = ifp->idev;
struct net_device *dev = idev->dev;
+ bool notify = false;
addrconf_join_solict(dev, &ifp->addr);
@@ -3583,7 +3584,7 @@ static void addrconf_dad_begin(struct inet6_ifaddr *ifp)
/* Because optimistic nodes can use this address,
* notify listeners. If DAD fails, RTM_DELADDR is sent.
*/
- ipv6_ifa_notify(RTM_NEWADDR, ifp);
+ notify = true;
}
}
@@ -3591,6 +3592,8 @@ static void addrconf_dad_begin(struct inet6_ifaddr *ifp)
out:
spin_unlock(&ifp->lock);
read_unlock_bh(&idev->lock);
+ if (notify)
+ ipv6_ifa_notify(RTM_NEWADDR, ifp);
}
static void addrconf_dad_start(struct inet6_ifaddr *ifp)