* [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
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