| Message ID | 2cf017eba84341c95d22fda2952a3f6f.squirrel@www.codeaurora.org |
|---|---|
| State | Changes Requested, archived |
| Delegated to: | David Miller |
| Headers | show |
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c index 2163871..ae8ac1a 100644 --- a/net/ipv6/addrconf.c +++ b/net/ipv6/addrconf.c @@ -3301,7 +3301,9 @@ 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. */ + read_unlock_bh(&idev->lock); ipv6_ifa_notify(RTM_NEWADDR, ifp); + read_lock_bh(&idev->lock); } }
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 then start 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 Change-Id: I270c05598622d400b178d758fdbd8296cf521ee8 Signed-off-by: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org> --- net/ipv6/addrconf.c | 2 ++ 1 file changed, 2 insertions(+) --