Messages in this thread Patch in this message | | | Date | Wed, 29 Oct 2014 19:07:34 +0100 | From | Peter Zijlstra <> | Subject | Re: e1000_netpoll(): disable_irq() triggers might_sleep() on linux-next |
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On Wed, Oct 29, 2014 at 04:56:20PM +0100, Sabrina Dubroca wrote: > commit e22b886a8a43b ("sched/wait: Add might_sleep() checks") included > in today's linux-next added a check that fires on e1000 with netpoll: > > > BUG: sleeping function called from invalid context at kernel/irq/manage.c:104 > in_atomic(): 1, irqs_disabled(): 1, pid: 1, name: systemd > no locks held by systemd/1. > irq event stamp: 10102965 > hardirqs last enabled at (10102965): [<ffffffff810cbafd>] vprintk_emit+0x2dd/0x6a0 > hardirqs last disabled at (10102964): [<ffffffff810cb897>] vprintk_emit+0x77/0x6a0 > softirqs last enabled at (10102342): [<ffffffff810666aa>] __do_softirq+0x27a/0x6f0 > softirqs last disabled at (10102337): [<ffffffff81066e86>] irq_exit+0x56/0xe0 > Preemption disabled at:[<ffffffff817de50d>] printk_emit+0x31/0x33 > > CPU: 1 PID: 1 Comm: systemd Not tainted 3.18.0-rc2-next-20141029-dirty #222 > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.7.5-20140617_173321-var-lib-archbuild-testing-x86_64-tobias 04/01/2014 > ffffffff81a82291 ffff88001e743978 ffffffff817df31d 0000000000000000 > 0000000000000000 ffff88001e7439a8 ffffffff8108dfa2 ffff88001e7439a8 > ffffffff81a82291 0000000000000068 0000000000000000 ffff88001e7439d8 > Call Trace: > [<ffffffff817df31d>] dump_stack+0x4f/0x7c > [<ffffffff8108dfa2>] ___might_sleep+0x182/0x2b0 > [<ffffffff8108e10a>] __might_sleep+0x3a/0xc0 > [<ffffffff810ce358>] synchronize_irq+0x38/0xa0 > [<ffffffff810ce690>] disable_irq+0x20/0x30 > [<ffffffff815d7253>] e1000_netpoll+0x23/0x60 > [<ffffffff81678d02>] netpoll_poll_dev+0x72/0x3a0 > [<ffffffff816791e7>] netpoll_send_skb_on_dev+0x1b7/0x2e0 > [<ffffffff816795f3>] netpoll_send_udp+0x2e3/0x490
Oh cute.. not entirely sure what to do there. This only works if you _know_ desc->threads_active will never be !0.
The best I can come up with is something like this, which avoids the might_sleep() in the one special case.
Thomas?
--- kernel/irq/manage.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c index 0a9104b4608b..b7cb736a8b32 100644 --- a/kernel/irq/manage.c +++ b/kernel/irq/manage.c @@ -100,8 +100,11 @@ void synchronize_irq(unsigned int irq) * running. Now verify that no threaded handlers are * active. */ - wait_event(desc->wait_for_threads, - !atomic_read(&desc->threads_active)); + if (atomic_read(&desc->threads_active)) { + might_sleep(); + __wait_event(desc->wait_for_threads, + !atomic_read(&desc->threads_active)); + } } } EXPORT_SYMBOL(synchronize_irq);
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