Re: [PATCH] tipc: fix a potential deadlock on &tx->lock
From: Jacob Keller <jacob.e.keller@intel.com>
Date: 2023-09-29 20:18:06
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On 9/27/2023 11:14 AM, Chengfeng Ye wrote:
It seems that tipc_crypto_key_revoke() could be be invoked by wokequeue tipc_crypto_work_rx() under process context and timer/rx callback under softirq context, thus the lock acquisition on &tx->lock seems better use spin_lock_bh() to prevent possible deadlock. This flaw was found by an experimental static analysis tool I am developing for irq-related deadlock.
Interesting.
tipc_crypto_work_rx() <workqueue> --> tipc_crypto_key_distr() --> tipc_bcast_xmit() --> tipc_bcbase_xmit() --> tipc_bearer_bc_xmit() --> tipc_crypto_xmit() --> tipc_ehdr_build() --> tipc_crypto_key_revoke() --> spin_lock(&tx->lock) <timer interrupt> --> tipc_disc_timeout() --> tipc_bearer_xmit_skb() --> tipc_crypto_xmit() --> tipc_ehdr_build() --> tipc_crypto_key_revoke() --> spin_lock(&tx->lock) <deadlock here> Signed-off-by: Chengfeng Ye <redacted> ---
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
quoted hunk ↗ jump to hunk
net/tipc/crypto.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)diff --git a/net/tipc/crypto.c b/net/tipc/crypto.c index 302fd749c424..43c3f1c971b8 100644 --- a/net/tipc/crypto.c +++ b/net/tipc/crypto.c@@ -1441,14 +1441,14 @@ static int tipc_crypto_key_revoke(struct net *net, u8 tx_key) struct tipc_crypto *tx = tipc_net(net)->crypto_tx; struct tipc_key key; - spin_lock(&tx->lock); + spin_lock_bh(&tx->lock); key = tx->key; WARN_ON(!key.active || tx_key != key.active); /* Free the active key */ tipc_crypto_key_set_state(tx, key.passive, 0, key.pending); tipc_crypto_key_detach(tx->aead[key.active], &tx->lock); - spin_unlock(&tx->lock); + spin_unlock_bh(&tx->lock); pr_warn("%s: key is revoked\n", tx->name); return -EKEYREVOKED;