[3.16.y-ckt stable] Patch "vgaarb: fix signal handling in vga_get()" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    vgaarb: fix signal handling in vga_get()

to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.16.y-queue

This patch is scheduled to be released in version 3.16.7-ckt23.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.16.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

---8<------------------------------------------------------------

>From ccd3c87a73c5fff50220339a6a61736c99c61370 Mon Sep 17 00:00:00 2001
From: "Kirill A. Shutemov" <kirill at shutemov.name>
Date: Mon, 30 Nov 2015 04:17:31 +0200
Subject: vgaarb: fix signal handling in vga_get()

commit 9f5bd30818c42c6c36a51f93b4df75a2ea2bd85e upstream.

There are few defects in vga_get() related to signal hadning:

  - we shouldn't check for pending signals for TASK_UNINTERRUPTIBLE
    case;

  - if we found pending signal we must remove ourself from wait queue
    and change task state back to running;

  - -ERESTARTSYS is more appropriate, I guess.

Signed-off-by: Kirill A. Shutemov <kirill at shutemov.name>
Reviewed-by: David Herrmann <dh.herrmann at gmail.com>
Signed-off-by: Dave Airlie <airlied at redhat.com>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/gpu/vga/vgaarb.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/vga/vgaarb.c b/drivers/gpu/vga/vgaarb.c
index 366641d0483f..5b9eccd3e9ff 100644
--- a/drivers/gpu/vga/vgaarb.c
+++ b/drivers/gpu/vga/vgaarb.c
@@ -393,8 +393,10 @@ int vga_get(struct pci_dev *pdev, unsigned int rsrc, int interruptible)
 		set_current_state(interruptible ?
 				  TASK_INTERRUPTIBLE :
 				  TASK_UNINTERRUPTIBLE);
-		if (signal_pending(current)) {
-			rc = -EINTR;
+		if (interruptible && signal_pending(current)) {
+			__set_current_state(TASK_RUNNING);
+			remove_wait_queue(&vga_wait_queue, &wait);
+			rc = -ERESTARTSYS;
 			break;
 		}
 		schedule();