Re: FAILED: patch "[PATCH] xhci: make sure interrupts are restored to correct state" failed to apply to 4.19-stable tree

[Sasha Levin <sashal@kernel.org>]

On Sun, Dec 15, 2019 at 10:27:46AM +0100, gregkh@linuxfoundation.org wrote:
>
>The patch below does not apply to the 4.19-stable tree.
>If someone wants it applied there, or to any other stable or longterm
>tree, then please email the backport, including the original git commit
>id to <stable@vger.kernel.org>.
>
>thanks,
>
>greg k-h
>
>------------------ original commit in Linus's tree ------------------
>
>From bd82873f23c9a6ad834348f8b83f3b6a5bca2c65 Mon Sep 17 00:00:00 2001
>From: Mathias Nyman <mathias.nyman@linux.intel.com>
>Date: Wed, 11 Dec 2019 16:20:07 +0200
>Subject: [PATCH] xhci: make sure interrupts are restored to correct state
>
>spin_unlock_irqrestore() might be called with stale flags after
>reading port status, possibly restoring interrupts to a incorrect
>state.
>
>If a usb2 port just finished resuming while the port status is read
>the spin lock will be temporary released and re-acquired in a separate
>function. The flags parameter is passed as value instead of a pointer,
>not updating flags properly before the final spin_unlock_irqrestore()
>is called.
>
>Cc: <stable@vger.kernel.org> # v3.12+
>Fixes: 8b3d45705e54 ("usb: Fix xHCI host issues on remote wakeup.")
>Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
>Link: https://lore.kernel.org/r/20191211142007.8847-7-mathias.nyman@linux.intel.com
>Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

There were quite a few code movements around this:

	e67ebf1b3815 ("xhci: move usb2 get port status link resume handling to its own function")
	5f78a54f8d31 ("xhci: move usb3 speficic bits to own function in get_port_status call")
	70e9b53dfedc ("xhci: move usb2 speficic bits to own function in get_port_status call")

I've fixed up the original patch to work around that and queued for 4.19
- 4.4.

-- 
Thanks,
Sasha