From dd47fbd40e6ea6884e295e13a2e50b0894258fdf Mon Sep 17 00:00:00 2001 From: Mauro Carvalho Chehab Date: Tue, 16 Feb 2016 07:22:27 -0200 Subject: [PATCH] [media] smsusb: don't sleep while atomic smscore_getbuffer() calls internally wait_event(), with can sleep. As smsusb_onresponse() is called on interrupt context, this causes the following warning: BUG: sleeping function called from invalid context at drivers/media/common/siano/smscoreapi.c:1653 in_atomic(): 1, irqs_disabled(): 1, pid: 11084, name: systemd-udevd INFO: lockdep is turned off. irq event stamp: 0 hardirqs last enabled at (0): [< (null)>] (null) hardirqs last disabled at (0): [] copy_process.part.7+0x10e7/0x56d0 softirqs last enabled at (0): [] copy_process.part.7+0x1183/0x56d0 softirqs last disabled at (0): [< (null)>] (null) CPU: 2 PID: 11084 Comm: systemd-udevd Tainted: G B W 4.5.0-rc3+ #47 Hardware name: /NUC5i7RYB, BIOS RYBDWi35.86A.0350.2015.0812.1722 08/12/2015 0000000000000000 ffff8803c6907a80 ffffffff81933901 ffff8802bd916000 ffff8802bd9165c8 ffff8803c6907aa8 ffffffff811c6af5 ffff8802bd916000 ffffffffa0ce9b60 0000000000000675 ffff8803c6907ae8 ffffffff811c6ce5 Call Trace: [] dump_stack+0x85/0xc4 [] ___might_sleep+0x245/0x3a0 [] __might_sleep+0x95/0x1a0 [] ? list_add_locked+0xca/0x140 [smsmdtv] [] smscore_getbuffer+0x7d/0x120 [smsmdtv] [] ? trace_hardirqs_off+0xd/0x10 [] ? smscore_sendrequest_and_wait.isra.5+0x120/0x120 [smsmdtv] [] ? list_add_locked+0xca/0x140 [smsmdtv] [] ? smscore_putbuffer+0x3a/0x40 [smsmdtv] [] smsusb_submit_urb+0x2ec/0x4f0 [smsusb] [] smsusb_onresponse+0x476/0x720 [smsusb] Let's add a work queue to handle the bottom half, preventing this problem. Signed-off-by: Mauro Carvalho Chehab --- drivers/media/usb/siano/smsusb.c | 19 ++++++++++++++++++- 1 file changed, 18 insertions(+), 1 deletion(-) diff --git a/drivers/media/usb/siano/smsusb.c b/drivers/media/usb/siano/smsusb.c index 8abbd3cc8eba..9fac9779f616 100644 --- a/drivers/media/usb/siano/smsusb.c +++ b/drivers/media/usb/siano/smsusb.c @@ -51,6 +51,9 @@ struct smsusb_urb_t { struct smsusb_device_t *dev; struct urb urb; + + /* For the bottom half */ + struct work_struct wq; }; struct smsusb_device_t { @@ -70,6 +73,18 @@ struct smsusb_device_t { static int smsusb_submit_urb(struct smsusb_device_t *dev, struct smsusb_urb_t *surb); +/** + * Completing URB's callback handler - bottom half (proccess context) + * submits the URB prepared on smsusb_onresponse() + */ +static void do_submit_urb(struct work_struct *work) +{ + struct smsusb_urb_t *surb = container_of(work, struct smsusb_urb_t, wq); + struct smsusb_device_t *dev = surb->dev; + + smsusb_submit_urb(dev, surb); +} + /** * Completing URB's callback handler - top half (interrupt context) * adds completing sms urb to the global surbs list and activtes the worker @@ -138,13 +153,15 @@ static void smsusb_onresponse(struct urb *urb) exit_and_resubmit: - smsusb_submit_urb(dev, surb); + INIT_WORK(&surb->wq, do_submit_urb); + schedule_work(&surb->wq); } static int smsusb_submit_urb(struct smsusb_device_t *dev, struct smsusb_urb_t *surb) { if (!surb->cb) { + /* This function can sleep */ surb->cb = smscore_getbuffer(dev->coredev); if (!surb->cb) { pr_err("smscore_getbuffer(...) returned NULL\n");