[PATCH v4 1/3] Bluetooth: bnep: fix possible might sleep error in bnep_session
From: Jeffy Chen <hidden>
Date: 2017-02-14 00:56:16
Also in:
lkml, netdev
Subsystem:
bluetooth subsystem, the rest · Maintainers:
Marcel Holtmann, Luiz Augusto von Dentz, Linus Torvalds
It looks like bnep_session has same pattern as the issue reported in
old rfcomm:
while (1) {
set_current_state(TASK_INTERRUPTIBLE);
if (condition)
break;
// may call might_sleep here
schedule();
}
__set_current_state(TASK_RUNNING);
Which fixed at:
dfb2fae Bluetooth: Fix nested sleeps
So let's fix it at the same way, also follow the suggestion of:
https://lwn.net/Articles/628628/
Signed-off-by: Jeffy Chen <redacted>
Reviewed-by: Brian Norris <briannorris@chromium.org>
---
Changes in v3:
Add brian's Reviewed-by.
Changes in v2:
Remove unnecessary memory barrier before wake_up_* functions.
net/bluetooth/bnep/core.c | 11 +++++------
1 file changed, 5 insertions(+), 6 deletions(-)
diff --git a/net/bluetooth/bnep/core.c b/net/bluetooth/bnep/core.c
index fbf251f..4d6b94d 100644
--- a/net/bluetooth/bnep/core.c
+++ b/net/bluetooth/bnep/core.c@@ -484,16 +484,16 @@ static int bnep_session(void *arg) struct net_device *dev = s->dev; struct sock *sk = s->sock->sk; struct sk_buff *skb; - wait_queue_t wait; + DEFINE_WAIT_FUNC(wait, woken_wake_function); BT_DBG(""); set_user_nice(current, -15); - init_waitqueue_entry(&wait, current); add_wait_queue(sk_sleep(sk), &wait); while (1) { - set_current_state(TASK_INTERRUPTIBLE); + /* Ensure session->terminate is updated */ + smp_mb__before_atomic(); if (atomic_read(&s->terminate)) break;
@@ -515,9 +515,8 @@ static int bnep_session(void *arg) break; netif_wake_queue(dev); - schedule(); + wait_woken(&wait, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT); } - __set_current_state(TASK_RUNNING); remove_wait_queue(sk_sleep(sk), &wait); /* Cleanup session */
@@ -666,7 +665,7 @@ int bnep_del_connection(struct bnep_conndel_req *req) s = __bnep_get_session(req->dst); if (s) { atomic_inc(&s->terminate); - wake_up_process(s->task); + wake_up_interruptible(sk_sleep(s->sock->sk)); } else err = -ENOENT;
--
2.1.4