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net/smc: wait for pending work before clcsock release_sock 

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>
This commit is contained in:
Karsten Graul 2019-04-11 11:17:30 +02:00 committed by David S. Miller
parent 988dc4a9a3
commit fd57770dd1
3 changed files with 30 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

14
net/smc/af_smc.c
View File

@ -167,10 +167,9 @@ 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);
@ -1037,13 +1036,13 @@ 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);
@ -1237,6 +1236,9 @@ 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;

25
net/smc/smc_close.c
View File

@ -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;
@ -321,6 +337,7 @@ 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;
@ -400,13 +417,13 @@ 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 */
}

1
net/smc/smc_close.h
View File

@ -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 */