https://github.com/torvalds/linux
Revision 63aea0dbab90a2461faaae357cbc8cfd6c8de9fe authored by Alan Stern on 17 May 2017, 15:32:03 UTC, committed by Greg Kroah-Hartman on 18 May 2017, 13:19:42 UTC
With threaded interrupts, bottom-half handlers are called with interrupts enabled. Therefore they can't safely use spin_lock(); they have to use spin_lock_irqsave(). Lockdep warns about a violation occurring in xhci_irq(): ========================================================= [ INFO: possible irq lock inversion dependency detected ] 4.11.0-rc8-dbg+ #1 Not tainted --------------------------------------------------------- swapper/7/0 just changed the state of lock: (&(&ehci->lock)->rlock){-.-...}, at: [<ffffffffa0130a69>] ehci_hrtimer_func+0x29/0xc0 [ehci_hcd] but this lock took another, HARDIRQ-unsafe lock in the past: (hcd_urb_list_lock){+.....} and interrupts could create inverse lock ordering between them. other info that might help us debug this: Possible interrupt unsafe locking scenario: CPU0 CPU1 ---- ---- lock(hcd_urb_list_lock); local_irq_disable(); lock(&(&ehci->lock)->rlock); lock(hcd_urb_list_lock); <Interrupt> lock(&(&ehci->lock)->rlock); *** DEADLOCK *** no locks held by swapper/7/0. the shortest dependencies between 2nd lock and 1st lock: -> (hcd_urb_list_lock){+.....} ops: 252 { HARDIRQ-ON-W at: __lock_acquire+0x602/0x1280 lock_acquire+0xd5/0x1c0 _raw_spin_lock+0x2f/0x40 usb_hcd_unlink_urb_from_ep+0x1b/0x60 [usbcore] xhci_giveback_urb_in_irq.isra.45+0x70/0x1b0 [xhci_hcd] finish_td.constprop.60+0x1d8/0x2e0 [xhci_hcd] xhci_irq+0xdd6/0x1fa0 [xhci_hcd] usb_hcd_irq+0x26/0x40 [usbcore] irq_forced_thread_fn+0x2f/0x70 irq_thread+0x149/0x1d0 kthread+0x113/0x150 ret_from_fork+0x2e/0x40 This patch fixes the problem. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Reported-and-tested-by: Bart Van Assche <bart.vanassche@sandisk.com> CC: <stable@vger.kernel.org> Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
1 parent 6a29bee
Tip revision: 63aea0dbab90a2461faaae357cbc8cfd6c8de9fe authored by Alan Stern on 17 May 2017, 15:32:03 UTC
USB: xhci: fix lock-inversion problem
USB: xhci: fix lock-inversion problem
Tip revision: 63aea0d
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