[PATCH] net: decnet: Fix sleeping inside in af_decnet

[PATCH] net: decnet: Fix sleeping inside in af_decnet

[Yajun Deng]

The release_sock() is blocking function, it would change the state
after sleeping. use wait_woken() instead.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Yajun Deng <yajun.deng@linux.dev>
---
 net/decnet/af_decnet.c | 27 ++++++++++++---------------
 1 file changed, 12 insertions(+), 15 deletions(-)

diff --git a/net/decnet/af_decnet.c b/net/decnet/af_decnet.c
index 5dbd45dc35ad..dc92a67baea3 100644
--- a/net/decnet/af_decnet.c
+++ b/net/decnet/af_decnet.c
@@ -816,7 +816,7 @@ static int dn_auto_bind(struct socket *sock)
 static int dn_confirm_accept(struct sock *sk, long *timeo, gfp_t allocation)
 {
 	struct dn_scp *scp = DN_SK(sk);
-	DEFINE_WAIT(wait);
+	DEFINE_WAIT_FUNC(wait, woken_wake_function);
 	int err;
 
 	if (scp->state != DN_CR)
@@ -826,11 +826,11 @@ static int dn_confirm_accept(struct sock *sk, long *timeo, gfp_t allocation)
 	scp->segsize_loc = dst_metric_advmss(__sk_dst_get(sk));
 	dn_send_conn_conf(sk, allocation);
 
-	prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
+	add_wait_queue(sk_sleep(sk), &wait);
 	for(;;) {
 		release_sock(sk);
 		if (scp->state == DN_CC)
-			*timeo = schedule_timeout(*timeo);
+			*timeo = wait_woken(&wait, TASK_INTERRUPTIBLE, *timeo);
 		lock_sock(sk);
 		err = 0;
 		if (scp->state == DN_RUN)
@@ -844,9 +844,8 @@ static int dn_confirm_accept(struct sock *sk, long *timeo, gfp_t allocation)
 		err = -EAGAIN;
 		if (!*timeo)
 			break;
-		prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
 	}
-	finish_wait(sk_sleep(sk), &wait);
+	remove_wait_queue(sk_sleep(sk), &wait);
 	if (err == 0) {
 		sk->sk_socket->state = SS_CONNECTED;
 	} else if (scp->state != DN_CC) {
@@ -858,7 +857,7 @@ static int dn_confirm_accept(struct sock *sk, long *timeo, gfp_t allocation)
 static int dn_wait_run(struct sock *sk, long *timeo)
 {
 	struct dn_scp *scp = DN_SK(sk);
-	DEFINE_WAIT(wait);
+	DEFINE_WAIT_FUNC(wait, woken_wake_function);
 	int err = 0;
 
 	if (scp->state == DN_RUN)
@@ -867,11 +866,11 @@ static int dn_wait_run(struct sock *sk, long *timeo)
 	if (!*timeo)
 		return -EALREADY;
 
-	prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
+	add_wait_queue(sk_sleep(sk), &wait);
 	for(;;) {
 		release_sock(sk);
 		if (scp->state == DN_CI || scp->state == DN_CC)
-			*timeo = schedule_timeout(*timeo);
+			*timeo = wait_woken(&wait, TASK_INTERRUPTIBLE, *timeo);
 		lock_sock(sk);
 		err = 0;
 		if (scp->state == DN_RUN)
@@ -885,9 +884,8 @@ static int dn_wait_run(struct sock *sk, long *timeo)
 		err = -ETIMEDOUT;
 		if (!*timeo)
 			break;
-		prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
 	}
-	finish_wait(sk_sleep(sk), &wait);
+	remove_wait_queue(sk_sleep(sk), &wait);
 out:
 	if (err == 0) {
 		sk->sk_socket->state = SS_CONNECTED;
@@ -1032,16 +1030,16 @@ static void dn_user_copy(struct sk_buff *skb, struct optdata_dn *opt)
 
 static struct sk_buff *dn_wait_for_connect(struct sock *sk, long *timeo)
 {
-	DEFINE_WAIT(wait);
+	DEFINE_WAIT_FUNC(wait, woken_wake_function);
 	struct sk_buff *skb = NULL;
 	int err = 0;
 
-	prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
+	add_wait_queue(sk_sleep(sk), &wait);
 	for(;;) {
 		release_sock(sk);
 		skb = skb_dequeue(&sk->sk_receive_queue);
 		if (skb == NULL) {
-			*timeo = schedule_timeout(*timeo);
+			*timeo = wait_woken(&wait, TASK_INTERRUPTIBLE, *timeo);
 			skb = skb_dequeue(&sk->sk_receive_queue);
 		}
 		lock_sock(sk);
@@ -1056,9 +1054,8 @@ static struct sk_buff *dn_wait_for_connect(struct sock *sk, long *timeo)
 		err = -EAGAIN;
 		if (!*timeo)
 			break;
-		prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
 	}
-	finish_wait(sk_sleep(sk), &wait);
+	remove_wait_queue(sk_sleep(sk), &wait);
 
 	return skb == NULL ? ERR_PTR(err) : skb;
 }
-- 
2.32.0

Re: [PATCH] net: decnet: Fix sleeping inside in af_decnet

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net.git (refs/heads/master):

On Wed, 14 Jul 2021 17:13:20 +0800 you wrote:
> The release_sock() is blocking function, it would change the state
> after sleeping. use wait_woken() instead.
> 
> Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
> Signed-off-by: Yajun Deng <yajun.deng@linux.dev>
> ---
>  net/decnet/af_decnet.c | 27 ++++++++++++---------------
>  1 file changed, 12 insertions(+), 15 deletions(-)

Here is the summary with links:
  - net: decnet: Fix sleeping inside in af_decnet
    https://git.kernel.org/netdev/net/c/5f119ba1d577

You are awesome, thank you!
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