Skip to content

Commit

Permalink
USB: fsl_usb2_udc: fix recursive lock
Browse files Browse the repository at this point in the history 
UDC needs to release lock before calling out to gadget driver, since
it may need to reenter.  The change fixes kernel BUG observed on rt
kernel.

> kernel BUG at kernel/rtmutex.c:683!
> stopped custom tracer.
> Oops: Exception in kernel mode, sig: 5 [#1]
> PREEMPT MPC834x ITX
> NIP: c021629c LR: c0216270 CTR: 00000000
> REGS: df761d70 TRAP: 0700   Not tainted  (2.6.23.9-rt13)
> MSR: 00021032 <ME,IR,DR>  CR: 28000022  XER: 00000000
> TASK = df632080[241] 'IRQ-38' THREAD: df760000
> GPR00: 00000001 df761e20 df632080 00000000 11111111 00000000 df761e6c
> 00000000
> GPR08: df761e48 00000000 df761e50 00000000 80000000 ede5cdde 1fffd000
> 00800000
> GPR16: ffffffff 00000000 007fff00 00000040 00000000 007ffeb0 00000000
> 1fff8b08
> GPR24: 00000000 00000026 00000000 df79a320 c026b2e8 c02240bc 00009032
> df79a320
> NIP [c021629c] rt_spin_lock_slowlock+0x9c/0x200
> LR [c0216270] rt_spin_lock_slowlock+0x70/0x200
> Call Trace:
> [df761e20] [c0216270] rt_spin_lock_slowlock+0x70/0x200 (unreliable)
> [df761e90] [c0182828] fsl_ep_disable+0xcc/0x154
> [df761eb0] [c0184d30] eth_reset_config+0x88/0x1d0
> [df761ed0] [c0184ec0] eth_disconnect+0x48/0x64
> [df761ef0] [c01831a4] reset_queues+0x60/0x78
> [df761f00] [c0183b74] fsl_udc_irq+0x9b8/0xa58
> [df761f50] [c003ef30] handle_IRQ_event+0x64/0x100
> [df761f80] [c003f758] thread_simple_irq+0x6c/0xc8
> [df761fa0] [c003f888] do_irqd+0xd4/0x2e4
> [df761fd0] [c0032284] kthread+0x50/0x8c
> [df761ff0] [c000f9b4] kernel_thread+0x44/0x60

Signed-off-by: Li Yang <leoli@freescale.com>
Cc: Eugene T. Bordenkircher <Eugene_Bordenkircher@selinc.com>
Acked-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
  • Loading branch information
Li Yang authored and Greg Kroah-Hartman committed May 29, 2008
1 parent a7f3872 commit 185e3de
Showing 1 changed file with 2 additions and 0 deletions.
2 changes: 2 additions & 0 deletions drivers/usb/gadget/fsl_usb2_udc.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1627,7 +1627,9 @@ static int reset_queues(struct fsl_udc *udc)
udc_reset_ep_queue(udc, pipe);

/* report disconnect; the driver is already quiesced */
spin_unlock(&udc->lock);
udc->driver->disconnect(&udc->gadget);
spin_lock(&udc->lock);

return 0;
}
Expand Down

0 comments on commit 185e3de

Please sign in to comment.