From: Albert Herranz <albert_herranz@xxxxxxxx> This patch fixes the following spinlock recursion bug seen when bringing down the ethernet interface. [ 87.354683] BUG: spinlock recursion on CPU#0, ifconfig/1722 [ 87.360899] lock: d2e01cd0, .magic: dead4ead, .owner: ifconfig/1722, .owner_cpu: 0 [ 87.373410] Call Trace: [ 87.379546] [d2f13c30] [c0008394] show_stack+0x3c/0x160 (unreliable) [ 87.386227] [d2f13c60] [c0169dd8] spin_bug+0x8c/0xd0 [ 87.392858] [d2f13c80] [c016a0e4] _raw_spin_lock+0xb4/0xb8 [ 87.399570] [d2f13c90] [c02c855c] _spin_lock_irqsave+0x30/0x48 [ 87.406258] [d2f13cb0] [c01aa5d4] defer_bh+0x28/0xfc [ 87.412726] [d2f13cd0] [c01c32e8] usb_hcd_giveback_urb+0x5c/0xdc [ 87.419209] [d2f13ce0] [c01d2cec] sthcd_giveback_urb+0x30/0x50 [ 87.425762] [d2f13d00] [c01d488c] sthcd_urb_dequeue+0x7c/0xac [ 87.432318] [d2f13d30] [c01c3478] unlink1+0x3c/0x4c [ 87.438960] [d2f13d40] [c01c45c8] usb_hcd_unlink_urb+0x88/0xa4 [ 87.445629] [d2f13d60] [c01c49ac] usb_unlink_urb+0x54/0x5c [ 87.452210] [d2f13d70] [c01aa170] unlink_urbs+0x40/0xb0 [ 87.458762] [d2f13d90] [c01ab470] usbnet_stop+0xdc/0x1a0 [ 87.465320] [d2f13df0] [c023bf18] dev_close+0xa0/0xdc [ 87.471639] [d2f13e00] [c023bc98] dev_change_flags+0x84/0x1b4 [ 87.477908] [d2f13e20] [c0283f50] devinet_ioctl+0x5ec/0x6b8 [ 87.484222] [d2f13e90] [c0284cbc] inet_ioctl+0x98/0xbc [ 87.490450] [d2f13ea0] [c022a300] sock_ioctl+0x60/0x284 [ 87.496566] [d2f13ec0] [c00a2714] vfs_ioctl+0x44/0xa8 [ 87.502657] [d2f13ee0] [c00a2d24] do_vfs_ioctl+0x88/0x24c [ 87.508707] [d2f13f10] [c00a2f28] sys_ioctl+0x40/0x74 [ 87.514728] [d2f13f40] [c0011bbc] ret_from_syscall+0x0/0x38 [ 87.520780] --- Exception: c01 at 0xff59878 [ 87.520783] LR = 0xff597dc unlink_urbs() takes the sk_buff queue lock &q->lock before removing the queued URBs via usb_unlink_urb(). The issue here is that the completion handler of a queued TX URB will get called when the URB is unlinked, then tx_complete() will call defer_bh() which will try to take the queue lock again and fail. The fix here is to release the list lock before unlinking a URB. Signed-off-by: Albert Herranz <albert_herranz@xxxxxxxx> Signed-off-by: Maximilian Schwerin <mvs@xxxxxxxxx> --- drivers/net/usb/usbnet.c | 2 ++ 1 files changed, 2 insertions(+), 0 deletions(-) diff --git a/drivers/net/usb/usbnet.c b/drivers/net/usb/usbnet.c index fae0fbd..b06bfd8 100644 --- a/drivers/net/usb/usbnet.c +++ b/drivers/net/usb/usbnet.c @@ -591,7 +591,9 @@ static int unlink_urbs (struct usbnet *dev, struct sk_buff_head *q) // during some PM-driven resume scenarios, // these (async) unlinks complete immediately + spin_unlock(&q->lock); retval = usb_unlink_urb (urb); + spin_lock(&q->lock); if (retval != -EINPROGRESS && retval != 0) netdev_dbg(dev->net, "unlink urb err, %d\n", retval); else -- 1.7.0.4 -- 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
