[PATCH RT] usb: Use _nort in usb_hcd_pci_remove

[Nate Dailey]

A trip through usb_hcd_pci_remove produces:

 BUG: sleeping function called from invalid context at kernel/locking/rtmutex.c:993
 in_atomic(): 0, irqs_disabled(): 1, pid: 4752, name: bash
 INFO: lockdep is turned off.
 irq event stamp: 0
 hardirqs last  enabled at (0): [<          (null)>]           (null)
 hardirqs last disabled at (0): [<ffffffff8108da9d>] copy_process.part.36+0x64d/0x2380
 softirqs last  enabled at (0): [<ffffffff8108da9d>] copy_process.part.36+0x64d/0x2380
 softirqs last disabled at (0): [<          (null)>]           (null)
 CPU: 1 PID: 4752 Comm: bash Tainted: G        W I     4.9.0debug-rt16+ #2
 Hardware name: Stratus ftServer 2700/G7LAY, BIOS BIOS Version 6.3:58 09/18/2014
 ffffc90006e5fbd0 ffffffff813d243a ffff88016ac0b240 0000000000001290
 ffffc90006e5fbf8 ffffffff810c6907 ffff8801682f45d0 ffff8801682f1000
 ffff8801682f45d0 ffffc90006e5fc18 ffffffff817dee44 ffff88016b2aee18
 Call Trace:
 [<ffffffff813d243a>] dump_stack+0x99/0xcf
 [<ffffffff810c6907>] ___might_sleep+0x137/0x210
 [<ffffffff817dee44>] rt_spin_lock+0x24/0x60
 [<ffffffff815b526f>] ehci_irq+0x2f/0x400
 [<ffffffff814226b9>] ? pci_bus_read_config_word+0x99/0xb0
 [<ffffffff81592d66>] usb_hcd_irq+0x26/0x40
 [<ffffffff815a7a90>] usb_hcd_pci_remove+0x50/0x170
 [<ffffffff815b933a>] ehci_pci_remove+0x1a/0x20
 [<ffffffff8142fc39>] pci_device_remove+0x39/0xc0
 [<ffffffff8152c4da>] __device_release_driver+0x9a/0x150
 [<ffffffff8152c5b3>] device_release_driver+0x23/0x30
 [<ffffffff81427f6c>] pci_stop_bus_device+0x8c/0xa0
 [<ffffffff8142808a>] pci_stop_and_remove_bus_device_locked+0x1a/0x30
 [<ffffffff8143182c>] remove_store+0x7c/0x90
 [<ffffffff81526508>] dev_attr_store+0x18/0x30
 [<ffffffff81313444>] sysfs_kf_write+0x44/0x60
 [<ffffffff81312d7c>] kernfs_fop_write+0x13c/0x1d0
 [<ffffffff81279bb7>] __vfs_write+0x37/0x160
 [<ffffffff81118c82>] ? rcu_sync_lockdep_assert+0x12/0x60
 [<ffffffff8127e3c6>] ? __sb_start_write+0x176/0x260
 [<ffffffff8127a3f4>] ? vfs_write+0x184/0x1b0
 [<ffffffff8127a325>] vfs_write+0xb5/0x1b0
 [<ffffffff810025e0>] ? syscall_trace_enter+0x1d0/0x380
 [<ffffffff8127b7e8>] SyS_write+0x58/0xc0
 [<ffffffff81002d0a>] do_syscall_64+0x7a/0x230
 [<ffffffff817df6c9>] entry_SYSCALL64_slow_path+0x25/0x25

Repro via something like:

> echo 1 > /sys/devices/pci0000:00/0000:00:01.0/0000:01:00.0/0000:02:01.0/0000:3d:00.0/0000:3e:01.0/0000:66:00.0/remove

Switching usb_hcd_pci_remove to use _nort variants prevents the BUG.

Signed-off-by: Nate Dailey <nate.dailey@xxxxxxxxxxx>
---
 drivers/usb/core/hcd-pci.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/core/hcd-pci.c b/drivers/usb/core/hcd-pci.c
index 7859d738df41..e9e7307028bc 100644
--- a/drivers/usb/core/hcd-pci.c
+++ b/drivers/usb/core/hcd-pci.c
@@ -341,9 +341,9 @@ void usb_hcd_pci_remove(struct pci_dev *dev)
 	 * to test whether the controller hardware has been removed (e.g.,
 	 * cardbus physical eject).
 	 */
-	local_irq_disable();
+	local_irq_disable_nort();
 	usb_hcd_irq(0, hcd);
-	local_irq_enable();
+	local_irq_enable_nort();
 
 	/* Note: dev_set_drvdata must be called while holding the rwsem */
 	if (dev->class == CL_EHCI) {
-- 
2.11.0