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| author | Oleg Nesterov <oleg@redhat.com> | 2023-11-17 17:48:46 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2024-02-23 08:24:55 +0100 |
| commit | 592d29eb6bd95781ea21cbb4a45a51260a98b009 (patch) | |
| tree | c026fae55d24e2483df028a357de4a7626607a6e /net | |
| parent | f4a0b57632fa83cdd3791118690ab2ee0d8efe1f (diff) | |
| download | linux-592d29eb6bd95781ea21cbb4a45a51260a98b009.tar.gz linux-592d29eb6bd95781ea21cbb4a45a51260a98b009.tar.bz2 linux-592d29eb6bd95781ea21cbb4a45a51260a98b009.zip | |
rxrpc_find_service_conn_rcu: fix the usage of read_seqbegin_or_lock()
[ Upstream commit bad1a11c0f061aa073bab785389fe04f19ba02e1 ]
rxrpc_find_service_conn_rcu() should make the "seq" counter odd on the
second pass, otherwise read_seqbegin_or_lock() never takes the lock.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
Link: https://lore.kernel.org/r/20231117164846.GA10410@redhat.com/
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'net')
| -rw-r--r-- | net/rxrpc/conn_service.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/net/rxrpc/conn_service.c b/net/rxrpc/conn_service.c index 21da48e3d2e5..7ad4b4e9341e 100644 --- a/net/rxrpc/conn_service.c +++ b/net/rxrpc/conn_service.c @@ -25,7 +25,7 @@ struct rxrpc_connection *rxrpc_find_service_conn_rcu(struct rxrpc_peer *peer, struct rxrpc_conn_proto k; struct rxrpc_skb_priv *sp = rxrpc_skb(skb); struct rb_node *p; - unsigned int seq = 0; + unsigned int seq = 1; k.epoch = sp->hdr.epoch; k.cid = sp->hdr.cid & RXRPC_CIDMASK; @@ -35,6 +35,7 @@ struct rxrpc_connection *rxrpc_find_service_conn_rcu(struct rxrpc_peer *peer, * under just the RCU read lock, so we have to check for * changes. */ + seq++; /* 2 on the 1st/lockless path, otherwise odd */ read_seqbegin_or_lock(&peer->service_conn_lock, &seq); p = rcu_dereference_raw(peer->service_conns.rb_node); |