Messages in this thread | | | Date | Thu, 7 Aug 2014 12:59:48 -0400 | From | chas williams - CONTRACTOR <> | Subject | Re: [setsockopt] WARNING: CPU: 0 PID: 1444 at kernel/sched/core.c:7088 __might_sleep+0x51/0x16f() |
| |
On Thu, 7 Aug 2014 17:17:41 +0200 Peter Zijlstra <peterz@infradead.org> wrote:
> Subject: atm: Fix blocking in wait loop > > One should not call blocking primitives inside a wait loop, since both > require task_struct::state to sleep, so the inner will destroy the outer > state. > > In this instance sigd_enq() will possible sleep for alloc_skb(), now if > I understand the code right, we do not actually need to call sigd_enq() > after the initial prepare_to_wait(), because we test the termination > condition before schedule() anyhow. > > So we can simply move it up a bit and avoid the entire confusion. > > Signed-off-by: Peter Zijlstra <peterz@infradead.org> > --- > net/atm/svc.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/net/atm/svc.c b/net/atm/svc.c > index d8e5d0c2ebbc..445ac238b69b 100644 > --- a/net/atm/svc.c > +++ b/net/atm/svc.c > @@ -297,8 +297,8 @@ static int svc_listen(struct socket *sock, int backlog) > goto out; > } > set_bit(ATM_VF_WAITING, &vcc->flags); > - prepare_to_wait(sk_sleep(sk), &wait, TASK_UNINTERRUPTIBLE); > sigd_enq(vcc, as_listen, NULL, NULL, &vcc->local); > + prepare_to_wait(sk_sleep(sk), &wait, TASK_UNINTERRUPTIBLE); > while (test_bit(ATM_VF_WAITING, &vcc->flags) && sigd) { > schedule(); > prepare_to_wait(sk_sleep(sk), &wait, TASK_UNINTERRUPTIBLE);
This isn't the only place that we queue a message for the signalling daemon after a prepare_to_wait() uninterruptibly so this patch would be incomplete as is.
What bothers me is the TASK_UNINTERRUPTIBLE -- I don't have a good reason why any of these should be sleeping uninterruptibly.
| |