From 5211c9729484c923f8d2e06bd29f9322cc42bb8f Mon Sep 17 00:00:00 2001 From: "D. Wythe" Date: Fri, 3 Nov 2023 14:07:38 +0800 Subject: [PATCH 1/3] net/smc: fix dangling sock under state SMC_APPFINCLOSEWAIT Considering scenario: smc_cdc_rx_handler __smc_release sock_set_flag smc_close_active() sock_set_flag __set_bit(DEAD) __set_bit(DONE) Dues to __set_bit is not atomic, the DEAD or DONE might be lost. if the DEAD flag lost, the state SMC_CLOSED will be never be reached in smc_close_passive_work: if (sock_flag(sk, SOCK_DEAD) && smc_close_sent_any_close(conn)) { sk->sk_state = SMC_CLOSED; } else { /* just shutdown, but not yet closed locally */ sk->sk_state = SMC_APPFINCLOSEWAIT; } Replace sock_set_flags or __set_bit to set_bit will fix this problem. Since set_bit is atomic. Fixes: b38d732477e4 ("smc: socket closing and linkgroup cleanup") Signed-off-by: D. Wythe Reviewed-by: Dust Li Signed-off-by: David S. Miller --- net/smc/af_smc.c | 4 ++-- net/smc/smc.h | 5 +++++ net/smc/smc_cdc.c | 2 +- net/smc/smc_close.c | 2 +- 4 files changed, 9 insertions(+), 4 deletions(-) diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c index abd2667734d4..da97f946b79b 100644 --- a/net/smc/af_smc.c +++ b/net/smc/af_smc.c @@ -275,7 +275,7 @@ static int __smc_release(struct smc_sock *smc) if (!smc->use_fallback) { rc = smc_close_active(smc); - sock_set_flag(sk, SOCK_DEAD); + smc_sock_set_flag(sk, SOCK_DEAD); sk->sk_shutdown |= SHUTDOWN_MASK; } else { if (sk->sk_state != SMC_CLOSED) { @@ -1743,7 +1743,7 @@ static int smc_clcsock_accept(struct smc_sock *lsmc, struct smc_sock **new_smc) if (new_clcsock) sock_release(new_clcsock); new_sk->sk_state = SMC_CLOSED; - sock_set_flag(new_sk, SOCK_DEAD); + smc_sock_set_flag(new_sk, SOCK_DEAD); sock_put(new_sk); /* final */ *new_smc = NULL; goto out; diff --git a/net/smc/smc.h b/net/smc/smc.h index 24745fde4ac2..e377980b8414 100644 --- a/net/smc/smc.h +++ b/net/smc/smc.h @@ -377,4 +377,9 @@ int smc_nl_dump_hs_limitation(struct sk_buff *skb, struct netlink_callback *cb); int smc_nl_enable_hs_limitation(struct sk_buff *skb, struct genl_info *info); int smc_nl_disable_hs_limitation(struct sk_buff *skb, struct genl_info *info); +static inline void smc_sock_set_flag(struct sock *sk, enum sock_flags flag) +{ + set_bit(flag, &sk->sk_flags); +} + #endif /* __SMC_H */ diff --git a/net/smc/smc_cdc.c b/net/smc/smc_cdc.c index 89105e95b452..01bdb7909a14 100644 --- a/net/smc/smc_cdc.c +++ b/net/smc/smc_cdc.c @@ -385,7 +385,7 @@ static void smc_cdc_msg_recv_action(struct smc_sock *smc, smc->sk.sk_shutdown |= RCV_SHUTDOWN; if (smc->clcsock && smc->clcsock->sk) smc->clcsock->sk->sk_shutdown |= RCV_SHUTDOWN; - sock_set_flag(&smc->sk, SOCK_DONE); + smc_sock_set_flag(&smc->sk, SOCK_DONE); sock_hold(&smc->sk); /* sock_put in close_work */ if (!queue_work(smc_close_wq, &conn->close_work)) sock_put(&smc->sk); diff --git a/net/smc/smc_close.c b/net/smc/smc_close.c index dbdf03e8aa5b..449ef454b53b 100644 --- a/net/smc/smc_close.c +++ b/net/smc/smc_close.c @@ -173,7 +173,7 @@ void smc_close_active_abort(struct smc_sock *smc) break; } - sock_set_flag(sk, SOCK_DEAD); + smc_sock_set_flag(sk, SOCK_DEAD); sk->sk_state_change(sk); if (release_clcsock) { From c5bf605ba4f9d6fbbb120595ab95002f4716edcb Mon Sep 17 00:00:00 2001 From: "D. Wythe" Date: Fri, 3 Nov 2023 14:07:39 +0800 Subject: [PATCH 2/3] net/smc: allow cdc msg send rather than drop it with NULL sndbuf_desc This patch re-fix the issues mentioned by commit 22a825c541d7 ("net/smc: fix NULL sndbuf_desc in smc_cdc_tx_handler()"). Blocking sending message do solve the issues though, but it also prevents the peer to receive the final message. Besides, in logic, whether the sndbuf_desc is NULL or not have no impact on the processing of cdc message sending. Hence that, this patch allows the cdc message sending but to check the sndbuf_desc with care in smc_cdc_tx_handler(). Fixes: 22a825c541d7 ("net/smc: fix NULL sndbuf_desc in smc_cdc_tx_handler()") Signed-off-by: D. Wythe Reviewed-by: Dust Li Signed-off-by: David S. Miller --- net/smc/smc_cdc.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) diff --git a/net/smc/smc_cdc.c b/net/smc/smc_cdc.c index 01bdb7909a14..3c06625ceb20 100644 --- a/net/smc/smc_cdc.c +++ b/net/smc/smc_cdc.c @@ -28,13 +28,15 @@ static void smc_cdc_tx_handler(struct smc_wr_tx_pend_priv *pnd_snd, { struct smc_cdc_tx_pend *cdcpend = (struct smc_cdc_tx_pend *)pnd_snd; struct smc_connection *conn = cdcpend->conn; + struct smc_buf_desc *sndbuf_desc; struct smc_sock *smc; int diff; + sndbuf_desc = conn->sndbuf_desc; smc = container_of(conn, struct smc_sock, conn); bh_lock_sock(&smc->sk); - if (!wc_status) { - diff = smc_curs_diff(cdcpend->conn->sndbuf_desc->len, + if (!wc_status && sndbuf_desc) { + diff = smc_curs_diff(sndbuf_desc->len, &cdcpend->conn->tx_curs_fin, &cdcpend->cursor); /* sndbuf_space is decreased in smc_sendmsg */ @@ -114,9 +116,6 @@ int smc_cdc_msg_send(struct smc_connection *conn, union smc_host_cursor cfed; int rc; - if (unlikely(!READ_ONCE(conn->sndbuf_desc))) - return -ENOBUFS; - smc_cdc_add_pending_send(conn, pend); conn->tx_cdc_seq++; From aa96fbd6d78d9770323b21e2c92bd38821be8852 Mon Sep 17 00:00:00 2001 From: "D. Wythe" Date: Fri, 3 Nov 2023 14:07:40 +0800 Subject: [PATCH 3/3] net/smc: put sk reference if close work was canceled Note that we always hold a reference to sock when attempting to submit close_work. Therefore, if we have successfully canceled close_work from pending, we MUST release that reference to avoid potential leaks. Fixes: 42bfba9eaa33 ("net/smc: immediate termination for SMCD link groups") Signed-off-by: D. Wythe Reviewed-by: Dust Li Signed-off-by: David S. Miller --- net/smc/smc_close.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/smc/smc_close.c b/net/smc/smc_close.c index 449ef454b53b..10219f55aad1 100644 --- a/net/smc/smc_close.c +++ b/net/smc/smc_close.c @@ -116,7 +116,8 @@ static void smc_close_cancel_work(struct smc_sock *smc) struct sock *sk = &smc->sk; release_sock(sk); - cancel_work_sync(&smc->conn.close_work); + if (cancel_work_sync(&smc->conn.close_work)) + sock_put(sk); cancel_delayed_work_sync(&smc->conn.tx_work); lock_sock(sk); }