3.16.75-rc1 review patch. If anyone has any objections, please let me know.
------------------
From: WANG Cong xiyou.wangcong@gmail.com
commit b4846fc3c8559649277e3e4e6b5cec5348a8d208 upstream.
Andrey reported a lockdep warning on non-initialized spinlock:
INFO: trying to register non-static key. the code is fine but needs lockdep annotation. turning off the locking correctness validator. CPU: 1 PID: 4099 Comm: a.out Not tainted 4.12.0-rc6+ #9 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:16 dump_stack+0x292/0x395 lib/dump_stack.c:52 register_lock_class+0x717/0x1aa0 kernel/locking/lockdep.c:755 ? 0xffffffffa0000000 __lock_acquire+0x269/0x3690 kernel/locking/lockdep.c:3255 lock_acquire+0x22d/0x560 kernel/locking/lockdep.c:3855 __raw_spin_lock_bh ./include/linux/spinlock_api_smp.h:135 _raw_spin_lock_bh+0x36/0x50 kernel/locking/spinlock.c:175 spin_lock_bh ./include/linux/spinlock.h:304 ip_mc_clear_src+0x27/0x1e0 net/ipv4/igmp.c:2076 igmpv3_clear_delrec+0xee/0x4f0 net/ipv4/igmp.c:1194 ip_mc_destroy_dev+0x4e/0x190 net/ipv4/igmp.c:1736
We miss a spin_lock_init() in igmpv3_add_delrec(), probably because previously we never use it on this code path. Since we already unlink it from the global mc_tomb list, it is probably safe not to acquire this spinlock here. It does not harm to have it although, to avoid conditional locking.
Fixes: c38b7d327aaf ("igmp: acquire pmc lock for ip_mc_clear_src()") Reported-by: Andrey Konovalov andreyknvl@google.com Signed-off-by: Cong Wang xiyou.wangcong@gmail.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Ben Hutchings ben@decadent.org.uk --- net/ipv4/igmp.c | 1 + 1 file changed, 1 insertion(+)
--- a/net/ipv4/igmp.c +++ b/net/ipv4/igmp.c @@ -1106,6 +1106,7 @@ static void igmpv3_add_delrec(struct in_ pmc = kzalloc(sizeof(*pmc), GFP_KERNEL); if (!pmc) return; + spin_lock_init(&pmc->lock); spin_lock_bh(&im->lock); pmc->interface = im->interface; in_dev_hold(in_dev);