Under certain circumstances lockdep finds an inconsistent lock state in gadgetfs. The problem can be reproduced with a hardware using the ci13xxx_udc driver and the gadgetfs test program (needs a patch to support the ci13xxx_udc, though): http://www.linux-usb.org/gadget/usb.c Start the test program, wait to initialize, then press Ctrl+c. This patch fixes the following problem by using spin_lock_irqsave() instead of spin_lock(). ================================= [ INFO: inconsistent lock state ] 3.1.0-rc6+ #158 --------------------------------- inconsistent {IN-HARDIRQ-W} -> {HARDIRQ-ON-W} usage. usb/113 [HC0[0]:SC0[0]:HE1:SE1] takes: (&(&dev->lock)->rlock){?.....}, at: [<bf000340>] gadgetfs_disconnect+0x14/0x80 [gadgetfs] {IN-HARDIRQ-W} state was registered at: [<c00596b8>] mark_irqflags+0x14c/0x1ac [<c0059bf8>] __lock_acquire+0x4e0/0x8f0 [<c005a698>] lock_acquire+0x98/0x1a8 [<c02f10e0>] _raw_spin_lock+0x54/0x8c [<bf000340>] gadgetfs_disconnect+0x14/0x80 [gadgetfs] [<c0229104>] _gadget_stop_activity+0xd4/0x154 [<c022b130>] isr_reset_handler+0x34/0x1c0 [<c022c320>] udc_irq+0x204/0x228 [<c0069018>] handle_irq_event_percpu+0x64/0x3a0 [<c0069390>] handle_irq_event+0x3c/0x5c [<c006ae5c>] handle_level_irq+0x8c/0x10c [<c0068a34>] generic_handle_irq+0x30/0x44 [<c0009b2c>] handle_IRQ+0x30/0x84 [<c0008ef8>] __irq_svc+0x38/0x60 [<c0009c58>] default_idle+0x30/0x34 [<c0009e30>] cpu_idle+0x9c/0xd8 [<c04056f4>] start_kernel+0x278/0x2bc irq event stamp: 6412 hardirqs last enabled at (6412): [<c02f1cd0>] _raw_spin_unlock_irqrestore+0x30/0x5c hardirqs last disabled at (6411): [<c02f1278>] _raw_spin_lock_irqsave+0x20/0xa0 softirqs last enabled at (6381): [<c002833c>] irq_exit+0xa0/0xa8 softirqs last disabled at (6372): [<c002833c>] irq_exit+0xa0/0xa8 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&(&dev->lock)->rlock); <Interrupt> lock(&(&dev->lock)->rlock); *** DEADLOCK *** 1 lock held by usb/113: #0: (udc_lock#2){+.+.+.}, at: [<c02286c0>] usb_gadget_unregister_driver+0x34/0x88 stack backtrace: [<c000d41c>] (unwind_backtrace+0x0/0xf0) from [<c0058e98>] (print_usage_bug+0x144/0x1c4) [<c0058e98>] (print_usage_bug+0x144/0x1c4) from [<c0059144>] (mark_lock_irq+0x22c/0x274) [<c0059144>] (mark_lock_irq+0x22c/0x274) from [<c00592d4>] (mark_lock+0x148/0x3e0) [<c00592d4>] (mark_lock+0x148/0x3e0) from [<c0059668>] (mark_irqflags+0xfc/0x1ac) [<c0059668>] (mark_irqflags+0xfc/0x1ac) from [<c0059bf8>] (__lock_acquire+0x4e0/0x8f0) [<c0059bf8>] (__lock_acquire+0x4e0/0x8f0) from [<c005a698>] (lock_acquire+0x98/0x1a8) [<c005a698>] (lock_acquire+0x98/0x1a8) from [<c02f10e0>] (_raw_spin_lock+0x54/0x8c) [<c02f10e0>] (_raw_spin_lock+0x54/0x8c) from [<bf000340>] (gadgetfs_disconnect+0x14/0x80 [gadgetfs]) [<bf000340>] (gadgetfs_disconnect+0x14/0x80 [gadgetfs]) from [<c0229104>] (_gadget_stop_activity+0xd4/0x154) [<c0229104>] (_gadget_stop_activity+0xd4/0x154) from [<c0229240>] (ci13xxx_stop+0xbc/0x17c) [<c0229240>] (ci13xxx_stop+0xbc/0x17c) from [<c022867c>] (usb_gadget_remove_driver+0x88/0x98) [<c022867c>] (usb_gadget_remove_driver+0x88/0x98) from [<c02286f4>] (usb_gadget_unregister_driver+0x68/0x88) [<c02286f4>] (usb_gadget_unregister_driver+0x68/0x88) from [<bf0003e8>] (dev_release+0x14/0x48 [gadgetfs]) [<bf0003e8>] (dev_release+0x14/0x48 [gadgetfs]) from [<c00cc158>] (__fput+0xa4/0x1f0) [<c00cc158>] (__fput+0xa4/0x1f0) from [<c00c7f28>] (filp_close+0x5c/0x74) [<c00c7f28>] (filp_close+0x5c/0x74) from [<c00c7fe8>] (sys_close+0xa8/0x150) [<c00c7fe8>] (sys_close+0xa8/0x150) from [<c00092a0>] (ret_fast_syscall+0x0/0x38) Signed-off-by: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx> --- drivers/usb/gadget/inode.c | 5 +++-- 1 files changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/usb/gadget/inode.c b/drivers/usb/gadget/inode.c index a392ec0..6ccae27 100644 --- a/drivers/usb/gadget/inode.c +++ b/drivers/usb/gadget/inode.c @@ -1730,8 +1730,9 @@ static void gadgetfs_disconnect (struct usb_gadget *gadget) { struct dev_data *dev = get_gadget_data (gadget); + unsigned long flags; - spin_lock (&dev->lock); + spin_lock_irqsave (&dev->lock, flags); if (dev->state == STATE_DEV_UNCONNECTED) goto exit; dev->state = STATE_DEV_UNCONNECTED; @@ -1740,7 +1741,7 @@ gadgetfs_disconnect (struct usb_gadget *gadget) next_event (dev, GADGETFS_DISCONNECT); ep0_readable (dev); exit: - spin_unlock (&dev->lock); + spin_unlock_irqrestore (&dev->lock, flags); } static void -- 1.7.6.3 -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
