diff mbox series

[06/11] net: xfrm: Use sequence counter with associated spinlock

Message ID 20210331081847.3547641-7-steffen.klassert@secunet.com (mailing list archive)
State Accepted
Commit bc8e0adff343d992ca76d871e8b5e6cb86e1fad9
Delegated to: Netdev Maintainers
Headers show
Series [01/11] xfrm: interface: fix ipv4 pmtu check to honor ip header df | expand

Checks

Context Check Description
netdev/tree_selection success Guessing tree name failed - patch did not apply

Commit Message

Steffen Klassert March 31, 2021, 8:18 a.m. UTC 
From: "Ahmed S. Darwish" <a.darwish@linutronix.de>

A sequence counter write section must be serialized or its internal
state can get corrupted. A plain seqcount_t does not contain the
information of which lock must be held to guaranteee write side
serialization.

For xfrm_state_hash_generation, use seqcount_spinlock_t instead of plain
seqcount_t.  This allows to associate the spinlock used for write
serialization with the sequence counter. It thus enables lockdep to
verify that the write serialization lock is indeed held before entering
the sequence counter write section.

If lockdep is disabled, this lock association is compiled out and has
neither storage size nor runtime overhead.

Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
---
 include/net/netns/xfrm.h | 2 +-
 net/xfrm/xfrm_state.c    | 3 ++-
 2 files changed, 3 insertions(+), 2 deletions(-)
diff mbox series

Patch

diff --git a/include/net/netns/xfrm.h b/include/net/netns/xfrm.h
index b59d73d529ba..e816b6a3ef2b 100644
--- a/include/net/netns/xfrm.h
+++ b/include/net/netns/xfrm.h
@@ -73,7 +73,7 @@  struct netns_xfrm {
 	struct dst_ops		xfrm6_dst_ops;
 #endif
 	spinlock_t		xfrm_state_lock;
-	seqcount_t		xfrm_state_hash_generation;
+	seqcount_spinlock_t	xfrm_state_hash_generation;
 
 	spinlock_t xfrm_policy_lock;
 	struct mutex xfrm_cfg_mutex;
diff --git a/net/xfrm/xfrm_state.c b/net/xfrm/xfrm_state.c
index ffd315cff984..4496f7efa220 100644
--- a/net/xfrm/xfrm_state.c
+++ b/net/xfrm/xfrm_state.c
@@ -2665,7 +2665,8 @@  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;
 
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