From 17aae888f2940f55065824bd7c267df06be47fbb Mon Sep 17 00:00:00 2001 From: "Ahmed S. Darwish" Date: Wed, 10 Jun 2020 12:53:22 +0200 Subject: [PATCH 182/323] xfrm: Use sequence counter with associated spinlock Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz A sequence counter write side critical section must be protected by some form of locking to serialize writers. A plain seqcount_t does not contain the information of which lock must be held when entering a write side critical section. Use the new seqcount_spinlock_t data type, which allows to associate a spinlock with the sequence counter. This enables lockdep to verify that the spinlock used for writer serialization is held when the write side critical section is entered. If lockdep is disabled this lock association is compiled out and has neither storage size nor runtime overhead. Upstream-status: The xfrm locking used for seqcoun writer serialization appears to be broken. If that's the case, a proper fix will need to be submitted upstream. (e.g. make the seqcount per network namespace?) Signed-off-by: Ahmed S. Darwish Signed-off-by: Sebastian Andrzej Siewior --- net/xfrm/xfrm_state.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/xfrm/xfrm_state.c b/net/xfrm/xfrm_state.c index ba73014805a4..14e1f36bdda5 100644 --- a/net/xfrm/xfrm_state.c +++ b/net/xfrm/xfrm_state.c @@ -2691,7 +2691,8 @@ int __net_init xfrm_state_init(struct net *net) net->xfrm.state_num = 0; INIT_WORK(&net->xfrm.state_hash_work, xfrm_hash_resize); spin_lock_init(&net->xfrm.xfrm_state_lock); - seqcount_init(&net->xfrm.xfrm_state_hash_generation); + seqcount_spinlock_init(&net->xfrm.xfrm_state_hash_generation, + &net->xfrm.xfrm_state_lock); return 0; out_byspi: -- 2.43.0