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authorSudeep Holla <sudeep.holla@arm.com>2015-03-04 17:07:57 +0000
committerFelipe Balbi <balbi@ti.com>2015-03-09 10:44:08 -0500
commit798523973dcc93c2440932dc4dfe76fbf571f668 (patch)
tree8176084ab1ca1c9864960c97159e1c523d5a0766 /drivers/usb/isp1760
parent9eccca0843205f87c00404b663188b88eb248051 (diff)
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usb: isp1760: fix possible deadlock in isp1760_udc_irq
Use spin_{un,}lock_irq{save,restore} in isp1760_udc_{start,stop} to prevent following potentially deadlock scenario between isp1760_udc_{start,stop} and isp1760_udc_irq : ================================= [ INFO: inconsistent lock state ] 4.0.0-rc2-00004-gf7bb2ef60173 #51 Not tainted --------------------------------- inconsistent {HARDIRQ-ON-W} -> {IN-HARDIRQ-W} usage. in:imklog/2118 [HC1[1]:SC0[0]:HE0:SE1] takes: (&(&udc->lock)->rlock){?.+...}, at: [<c0397a93>] isp1760_udc_irq+0x367/0x9dc {HARDIRQ-ON-W} state was registered at: [<c05135b3>] _raw_spin_lock+0x23/0x30 [<c0396b87>] isp1760_udc_start+0x23/0xf8 [<c039dc21>] udc_bind_to_driver+0x71/0xb0 [<c039de4f>] usb_gadget_probe_driver+0x53/0x9c [<bf80d0df>] usb_composite_probe+0x8a/0xa4 [libcomposite] [<bf8311a7>] 0xbf8311a7 [<c00088c5>] do_one_initcall+0x8d/0x17c [<c050b92d>] do_init_module+0x49/0x148 [<c0087323>] load_module+0xb7f/0xbc4 [<c0087471>] SyS_finit_module+0x51/0x74 [<c000d8c1>] ret_fast_syscall+0x1/0x68 irq event stamp: 4966 hardirqs last enabled at (4965): [<c05137df>] _raw_spin_unlock_irq+0x1f/0x24 hardirqs last disabled at (4966): [<c00110b3>] __irq_svc+0x33/0x64 softirqs last enabled at (4458): [<c0023475>] __do_softirq+0x23d/0x2d0 softirqs last disabled at (4389): [<c002380b>] irq_exit+0xef/0x15c other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&(&udc->lock)->rlock); <Interrupt> lock(&(&udc->lock)->rlock); *** DEADLOCK *** 1 lock held by in:imklog/2118: #0: (&f->f_pos_lock){+.+.+.}, at: [<c010a101>] __fdget_pos+0x31/0x34 Signed-off-by: Sudeep Holla <sudeep.holla@arm.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Felipe Balbi <balbi@ti.com>
Diffstat (limited to 'drivers/usb/isp1760')
-rw-r--r--drivers/usb/isp1760/isp1760-udc.c10
1 files changed, 6 insertions, 4 deletions
diff --git a/drivers/usb/isp1760/isp1760-udc.c b/drivers/usb/isp1760/isp1760-udc.c
index 9612d7990565..19e6a172ff82 100644
--- a/drivers/usb/isp1760/isp1760-udc.c
+++ b/drivers/usb/isp1760/isp1760-udc.c
@@ -1191,6 +1191,7 @@ static int isp1760_udc_start(struct usb_gadget *gadget,
struct usb_gadget_driver *driver)
{
struct isp1760_udc *udc = gadget_to_udc(gadget);
+ unsigned long flags;
/* The hardware doesn't support low speed. */
if (driver->max_speed < USB_SPEED_FULL) {
@@ -1198,7 +1199,7 @@ static int isp1760_udc_start(struct usb_gadget *gadget,
return -EINVAL;
}
- spin_lock(&udc->lock);
+ spin_lock_irqsave(&udc->lock, flags);
if (udc->driver) {
dev_err(udc->isp->dev, "UDC already has a gadget driver\n");
@@ -1208,7 +1209,7 @@ static int isp1760_udc_start(struct usb_gadget *gadget,
udc->driver = driver;
- spin_unlock(&udc->lock);
+ spin_unlock_irqrestore(&udc->lock, flags);
dev_dbg(udc->isp->dev, "starting UDC with driver %s\n",
driver->function);
@@ -1232,6 +1233,7 @@ static int isp1760_udc_start(struct usb_gadget *gadget,
static int isp1760_udc_stop(struct usb_gadget *gadget)
{
struct isp1760_udc *udc = gadget_to_udc(gadget);
+ unsigned long flags;
dev_dbg(udc->isp->dev, "%s\n", __func__);
@@ -1239,9 +1241,9 @@ static int isp1760_udc_stop(struct usb_gadget *gadget)
isp1760_udc_write(udc, DC_MODE, 0);
- spin_lock(&udc->lock);
+ spin_lock_irqsave(&udc->lock, flags);
udc->driver = NULL;
- spin_unlock(&udc->lock);
+ spin_unlock_irqrestore(&udc->lock, flags);
return 0;
}