* [PATCH] Bluetooth: hidp: might sleep error in hidp_session_thread
@ 2017-01-20 13:52 Jeffy Chen
2017-01-24 2:31 ` Brian Norris
0 siblings, 1 reply; 3+ messages in thread
From: Jeffy Chen @ 2017-01-20 13:52 UTC (permalink / raw)
To: linux-bluetooth
Cc: Brian Norris, Douglas Anderson, Jeffy Chen, Johan Hedberg, netdev,
linux-kernel, David S. Miller, Marcel Holtmann, Gustavo Padovan
[ 39.044329] do not call blocking ops when !TASK_RUNNING; state=1 set
at [<ffffffbffc290358>] hidp_session_thread+0x110/0x568 [hidp]
...
[ 40.159664] Call trace:
[ 40.162122] [<ffffffc00024ae08>] __might_sleep+0x64/0x90
[ 40.167443] [<ffffffc00080568c>] lock_sock_nested+0x30/0x78
[ 40.173047] [<ffffffbffc1b3ca0>] l2cap_sock_sendmsg+0x90/0xf0
[bluetooth]
[ 40.179842] [<ffffffc0008012c4>] sock_sendmsg+0x4c/0x68
[ 40.185072] [<ffffffc000801414>] kernel_sendmsg+0x54/0x68
[ 40.190477] [<ffffffbffc28f4d0>] hidp_send_frame+0x78/0xa0 [hidp]
[ 40.196574] [<ffffffbffc28f53c>] hidp_process_transmit+0x44/0x98
[hidp]
[ 40.203191] [<ffffffbffc2905ac>] hidp_session_thread+0x364/0x568
[hidp]
Following (https://lwn.net/Articles/628628/).
Signed-off-by: Jeffy Chen <jeffy.chen@rock-chips.com>
---
net/bluetooth/hidp/core.c | 15 +++++++++------
1 file changed, 9 insertions(+), 6 deletions(-)
diff --git a/net/bluetooth/hidp/core.c b/net/bluetooth/hidp/core.c
index 0bec458..bfd3fb8 100644
--- a/net/bluetooth/hidp/core.c
+++ b/net/bluetooth/hidp/core.c
@@ -1180,7 +1180,9 @@ static void hidp_session_run(struct hidp_session *session)
struct sock *ctrl_sk = session->ctrl_sock->sk;
struct sock *intr_sk = session->intr_sock->sk;
struct sk_buff *skb;
+ DEFINE_WAIT_FUNC(wait, woken_wake_function);
+ add_wait_queue(sk_sleep(intr_sk), &wait);
for (;;) {
/*
* This thread can be woken up two ways:
@@ -1188,12 +1190,10 @@ static void hidp_session_run(struct hidp_session *session)
* session->terminate flag and wakes this thread up.
* - Via modifying the socket state of ctrl/intr_sock. This
* thread is woken up by ->sk_state_changed().
- *
- * Note: set_current_state() performs any necessary
- * memory-barriers for us.
*/
- set_current_state(TASK_INTERRUPTIBLE);
+ /* Ensure session->terminate is updated */
+ smp_mb__before_atomic();
if (atomic_read(&session->terminate))
break;
@@ -1227,11 +1227,14 @@ static void hidp_session_run(struct hidp_session *session)
hidp_process_transmit(session, &session->ctrl_transmit,
session->ctrl_sock);
- schedule();
+ wait_woken(&wait, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT);
}
+ remove_wait_queue(sk_sleep(intr_sk), &wait);
atomic_inc(&session->terminate);
- set_current_state(TASK_RUNNING);
+
+ /* Ensure session->terminate is updated */
+ smp_mb__after_atomic();
}
/*
--
2.1.4
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] Bluetooth: hidp: might sleep error in hidp_session_thread
2017-01-20 13:52 [PATCH] Bluetooth: hidp: might sleep error in hidp_session_thread Jeffy Chen
@ 2017-01-24 2:31 ` Brian Norris
2017-01-24 7:29 ` jeffy
0 siblings, 1 reply; 3+ messages in thread
From: Brian Norris @ 2017-01-24 2:31 UTC (permalink / raw)
To: Jeffy Chen
Cc: linux-bluetooth, Douglas Anderson, Johan Hedberg, netdev,
linux-kernel, David S. Miller, Marcel Holtmann, Gustavo Padovan,
Peter Hurley, Peter Zijlstra, Guenter Roeck
Hi Jeffy,
On Fri, Jan 20, 2017 at 09:52:08PM +0800, Jeffy Chen wrote:
> [ 39.044329] do not call blocking ops when !TASK_RUNNING; state=1 set
> at [<ffffffbffc290358>] hidp_session_thread+0x110/0x568 [hidp]
> ...
> [ 40.159664] Call trace:
> [ 40.162122] [<ffffffc00024ae08>] __might_sleep+0x64/0x90
> [ 40.167443] [<ffffffc00080568c>] lock_sock_nested+0x30/0x78
> [ 40.173047] [<ffffffbffc1b3ca0>] l2cap_sock_sendmsg+0x90/0xf0
> [bluetooth]
> [ 40.179842] [<ffffffc0008012c4>] sock_sendmsg+0x4c/0x68
> [ 40.185072] [<ffffffc000801414>] kernel_sendmsg+0x54/0x68
> [ 40.190477] [<ffffffbffc28f4d0>] hidp_send_frame+0x78/0xa0 [hidp]
> [ 40.196574] [<ffffffbffc28f53c>] hidp_process_transmit+0x44/0x98
> [hidp]
> [ 40.203191] [<ffffffbffc2905ac>] hidp_session_thread+0x364/0x568
> [hidp]
Am I crazy, or are several other protocols broken like this too? I see a
similar structure in net/bluetooth/bnep/core.c and
net/bluetooth/cmtp/core.c, at least, each of which also call
kernel_sendmsg(), which might be an l2cap socket (...I think? I'm not a
bluetooth expert really).
>
> Following (https://lwn.net/Articles/628628/).
>
> Signed-off-by: Jeffy Chen <jeffy.chen@rock-chips.com>
> ---
>
> net/bluetooth/hidp/core.c | 15 +++++++++------
> 1 file changed, 9 insertions(+), 6 deletions(-)
>
> diff --git a/net/bluetooth/hidp/core.c b/net/bluetooth/hidp/core.c
> index 0bec458..bfd3fb8 100644
> --- a/net/bluetooth/hidp/core.c
> +++ b/net/bluetooth/hidp/core.c
> @@ -1180,7 +1180,9 @@ static void hidp_session_run(struct hidp_session *session)
> struct sock *ctrl_sk = session->ctrl_sock->sk;
> struct sock *intr_sk = session->intr_sock->sk;
> struct sk_buff *skb;
> + DEFINE_WAIT_FUNC(wait, woken_wake_function);
>
> + add_wait_queue(sk_sleep(intr_sk), &wait);
> for (;;) {
> /*
> * This thread can be woken up two ways:
> @@ -1188,12 +1190,10 @@ static void hidp_session_run(struct hidp_session *session)
> * session->terminate flag and wakes this thread up.
> * - Via modifying the socket state of ctrl/intr_sock. This
> * thread is woken up by ->sk_state_changed().
> - *
> - * Note: set_current_state() performs any necessary
> - * memory-barriers for us.
> */
> - set_current_state(TASK_INTERRUPTIBLE);
>
> + /* Ensure session->terminate is updated */
> + smp_mb__before_atomic();
> if (atomic_read(&session->terminate))
> break;
>
> @@ -1227,11 +1227,14 @@ static void hidp_session_run(struct hidp_session *session)
> hidp_process_transmit(session, &session->ctrl_transmit,
> session->ctrl_sock);
>
> - schedule();
> + wait_woken(&wait, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT);
I think this looks mostly good, except what about the
hidp_session_terminate() condition? In that case, you're running
wake_up_process() -- which won't set WQ_FLAG_WOKEN for us. So what
happens if we see a hidp_session_terminate() call in between the check
for the ->terminate count, but before we call wait_woken()? IIUC, I
think we'll just ignore the call and keep waiting for the next wake
signal.
I think you might need to rework hidp_session_terminate() too, to
actually target the wait queue and not just the processes.
IIUC, of course. I could be wrong...
Brian
> }
> + remove_wait_queue(sk_sleep(intr_sk), &wait);
>
> atomic_inc(&session->terminate);
> - set_current_state(TASK_RUNNING);
> +
> + /* Ensure session->terminate is updated */
> + smp_mb__after_atomic();
> }
>
> /*
> --
> 2.1.4
>
>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] Bluetooth: hidp: might sleep error in hidp_session_thread
2017-01-24 2:31 ` Brian Norris
@ 2017-01-24 7:29 ` jeffy
0 siblings, 0 replies; 3+ messages in thread
From: jeffy @ 2017-01-24 7:29 UTC (permalink / raw)
To: Brian Norris
Cc: linux-bluetooth, Douglas Anderson, Johan Hedberg, netdev,
linux-kernel, David S. Miller, Marcel Holtmann, Gustavo Padovan,
Peter Hurley, Peter Zijlstra, Guenter Roeck
Hi brian,
On 01/24/2017 10:31 AM, Brian Norris wrote:
> Hi Jeffy,
>
> On Fri, Jan 20, 2017 at 09:52:08PM +0800, Jeffy Chen wrote:
>> [ 39.044329] do not call blocking ops when !TASK_RUNNING; state=1 set
>> at [<ffffffbffc290358>] hidp_session_thread+0x110/0x568 [hidp]
>> ...
>> [ 40.159664] Call trace:
>> [ 40.162122] [<ffffffc00024ae08>] __might_sleep+0x64/0x90
>> [ 40.167443] [<ffffffc00080568c>] lock_sock_nested+0x30/0x78
>> [ 40.173047] [<ffffffbffc1b3ca0>] l2cap_sock_sendmsg+0x90/0xf0
>> [bluetooth]
>> [ 40.179842] [<ffffffc0008012c4>] sock_sendmsg+0x4c/0x68
>> [ 40.185072] [<ffffffc000801414>] kernel_sendmsg+0x54/0x68
>> [ 40.190477] [<ffffffbffc28f4d0>] hidp_send_frame+0x78/0xa0 [hidp]
>> [ 40.196574] [<ffffffbffc28f53c>] hidp_process_transmit+0x44/0x98
>> [hidp]
>> [ 40.203191] [<ffffffbffc2905ac>] hidp_session_thread+0x364/0x568
>> [hidp]
> Am I crazy, or are several other protocols broken like this too? I see a
> similar structure in net/bluetooth/bnep/core.c and
> net/bluetooth/cmtp/core.c, at least, each of which also call
> kernel_sendmsg(), which might be an l2cap socket (...I think? I'm not a
> bluetooth expert really).
Thanx, uploaded a new serial of patchset, which contains hidp & cmtp &
bnep:9534023/9534025/9534027
>
>> Following (https://lwn.net/Articles/628628/).
>>
>> Signed-off-by: Jeffy Chen <jeffy.chen@rock-chips.com>
>> ---
>>
>> net/bluetooth/hidp/core.c | 15 +++++++++------
>> 1 file changed, 9 insertions(+), 6 deletions(-)
>>
>> diff --git a/net/bluetooth/hidp/core.c b/net/bluetooth/hidp/core.c
>> index 0bec458..bfd3fb8 100644
>> --- a/net/bluetooth/hidp/core.c
>> +++ b/net/bluetooth/hidp/core.c
>> @@ -1180,7 +1180,9 @@ static void hidp_session_run(struct hidp_session *session)
>> struct sock *ctrl_sk = session->ctrl_sock->sk;
>> struct sock *intr_sk = session->intr_sock->sk;
>> struct sk_buff *skb;
>> + DEFINE_WAIT_FUNC(wait, woken_wake_function);
>>
>> + add_wait_queue(sk_sleep(intr_sk), &wait);
>> for (;;) {
>> /*
>> * This thread can be woken up two ways:
>> @@ -1188,12 +1190,10 @@ static void hidp_session_run(struct hidp_session *session)
>> * session->terminate flag and wakes this thread up.
>> * - Via modifying the socket state of ctrl/intr_sock. This
>> * thread is woken up by ->sk_state_changed().
>> - *
>> - * Note: set_current_state() performs any necessary
>> - * memory-barriers for us.
>> */
>> - set_current_state(TASK_INTERRUPTIBLE);
>>
>> + /* Ensure session->terminate is updated */
>> + smp_mb__before_atomic();
>> if (atomic_read(&session->terminate))
>> break;
>>
>> @@ -1227,11 +1227,14 @@ static void hidp_session_run(struct hidp_session *session)
>> hidp_process_transmit(session, &session->ctrl_transmit,
>> session->ctrl_sock);
>>
>> - schedule();
>> + wait_woken(&wait, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT);
> I think this looks mostly good, except what about the
> hidp_session_terminate() condition? In that case, you're running
> wake_up_process() -- which won't set WQ_FLAG_WOKEN for us. So what
> happens if we see a hidp_session_terminate() call in between the check
> for the ->terminate count, but before we call wait_woken()? IIUC, I
> think we'll just ignore the call and keep waiting for the next wake
> signal.
>
> I think you might need to rework hidp_session_terminate() too, to
> actually target the wait queue and not just the processes.
>
> IIUC, of course. I could be wrong...
Ok, that make sense, thanx for point that out.
>
> Brian
>
>> }
>> + remove_wait_queue(sk_sleep(intr_sk), &wait);
>>
>> atomic_inc(&session->terminate);
>> - set_current_state(TASK_RUNNING);
>> +
>> + /* Ensure session->terminate is updated */
>> + smp_mb__after_atomic();
>> }
>>
>> /*
>> --
>> 2.1.4
>>
>>
>
>
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2017-01-24 7:30 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2017-01-20 13:52 [PATCH] Bluetooth: hidp: might sleep error in hidp_session_thread Jeffy Chen
2017-01-24 2:31 ` Brian Norris
2017-01-24 7:29 ` jeffy
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).