4.19-stable review patch. If anyone has any objections, please let me know.
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From: Karsten Graul kgraul@linux.ibm.com
[ Upstream commit fd57770dd198f5b2ddd5b9e6bf282cf98d63adb9 ]
When the clcsock is already released using sock_release() and a pending smc_listen_work accesses the clcsock than that will fail. Solve this by canceling and waiting for the work to complete first. Because the work holds the sock_lock it must make sure that the lock is not hold before the new helper smc_clcsock_release() is invoked. And before the smc_listen_work starts working check if the parent listen socket is still valid, otherwise stop the work early.
Signed-off-by: Karsten Graul kgraul@linux.ibm.com Signed-off-by: Ursula Braun ubraun@linux.ibm.com Signed-off-by: David S. Miller davem@davemloft.net Stable-dep-of: 5211c9729484 ("net/smc: fix dangling sock under state SMC_APPFINCLOSEWAIT") Signed-off-by: Sasha Levin sashal@kernel.org --- net/smc/af_smc.c | 14 ++++++++------ net/smc/smc_close.c | 25 +++++++++++++++++++++---- net/smc/smc_close.h | 1 + 3 files changed, 30 insertions(+), 10 deletions(-)
diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c index 6f342f6cc4876..6b30bec54b624 100644 --- a/net/smc/af_smc.c +++ b/net/smc/af_smc.c @@ -158,10 +158,9 @@ static int smc_release(struct socket *sock)
if (sk->sk_state == SMC_CLOSED) { if (smc->clcsock) { - mutex_lock(&smc->clcsock_release_lock); - sock_release(smc->clcsock); - smc->clcsock = NULL; - mutex_unlock(&smc->clcsock_release_lock); + release_sock(sk); + smc_clcsock_release(smc); + lock_sock(sk); } if (!smc->use_fallback) smc_conn_free(&smc->conn); @@ -1014,13 +1013,13 @@ static void smc_listen_out(struct smc_sock *new_smc) struct smc_sock *lsmc = new_smc->listen_smc; struct sock *newsmcsk = &new_smc->sk;
- lock_sock_nested(&lsmc->sk, SINGLE_DEPTH_NESTING); if (lsmc->sk.sk_state == SMC_LISTEN) { + lock_sock_nested(&lsmc->sk, SINGLE_DEPTH_NESTING); smc_accept_enqueue(&lsmc->sk, newsmcsk); + release_sock(&lsmc->sk); } else { /* no longer listening */ smc_close_non_accepted(newsmcsk); } - release_sock(&lsmc->sk);
/* Wake up accept */ lsmc->sk.sk_data_ready(&lsmc->sk); @@ -1216,6 +1215,9 @@ static void smc_listen_work(struct work_struct *work) int rc = 0; u8 ibport;
+ if (new_smc->listen_smc->sk.sk_state != SMC_LISTEN) + return smc_listen_out_err(new_smc); + if (new_smc->use_fallback) { smc_listen_out_connected(new_smc); return; diff --git a/net/smc/smc_close.c b/net/smc/smc_close.c index 3e7858793d485..cac0773f5ebd9 100644 --- a/net/smc/smc_close.c +++ b/net/smc/smc_close.c @@ -21,6 +21,22 @@
#define SMC_CLOSE_WAIT_LISTEN_CLCSOCK_TIME (5 * HZ)
+/* release the clcsock that is assigned to the smc_sock */ +void smc_clcsock_release(struct smc_sock *smc) +{ + struct socket *tcp; + + if (smc->listen_smc && current_work() != &smc->smc_listen_work) + cancel_work_sync(&smc->smc_listen_work); + mutex_lock(&smc->clcsock_release_lock); + if (smc->clcsock) { + tcp = smc->clcsock; + smc->clcsock = NULL; + sock_release(tcp); + } + mutex_unlock(&smc->clcsock_release_lock); +} + static void smc_close_cleanup_listen(struct sock *parent) { struct sock *sk; @@ -331,6 +347,7 @@ static void smc_close_passive_work(struct work_struct *work) close_work); struct smc_sock *smc = container_of(conn, struct smc_sock, conn); struct smc_cdc_conn_state_flags *rxflags; + bool release_clcsock = false; struct sock *sk = &smc->sk; int old_state;
@@ -417,13 +434,13 @@ static void smc_close_passive_work(struct work_struct *work) if ((sk->sk_state == SMC_CLOSED) && (sock_flag(sk, SOCK_DEAD) || !sk->sk_socket)) { smc_conn_free(conn); - if (smc->clcsock) { - sock_release(smc->clcsock); - smc->clcsock = NULL; - } + if (smc->clcsock) + release_clcsock = true; } } release_sock(sk); + if (release_clcsock) + smc_clcsock_release(smc); sock_put(sk); /* sock_hold done by schedulers of close_work */ }
diff --git a/net/smc/smc_close.h b/net/smc/smc_close.h index 19eb6a211c23c..e0e3b5df25d24 100644 --- a/net/smc/smc_close.h +++ b/net/smc/smc_close.h @@ -23,5 +23,6 @@ void smc_close_wake_tx_prepared(struct smc_sock *smc); int smc_close_active(struct smc_sock *smc); int smc_close_shutdown_write(struct smc_sock *smc); void smc_close_init(struct smc_sock *smc); +void smc_clcsock_release(struct smc_sock *smc);
#endif /* SMC_CLOSE_H */