[3.16.y-ckt stable] Patch "drm/i915: avoid deadlock on failure paths in __intel_framebuffer_create()" has been added to the 3.16.y-ckt tree

[Luis Henriques]

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

    drm/i915: avoid deadlock on failure paths in __intel_framebuffer_create()

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-ckt24.

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 1646605d0abfcaa72380f8a2e2d13a7769380a19 Mon Sep 17 00:00:00 2001
From: Alexey Khoroshilov <khoroshilov at ispras.ru>
Date: Sat, 8 Nov 2014 01:41:23 +0300
Subject: drm/i915: avoid deadlock on failure paths in
 __intel_framebuffer_create()

commit 6ccb81f2171ab48592946efab0ce0fd41978f4ba upstream.

Since a8bb6818270c __intel_framebuffer_create() is called
with struct_mutex held, so it should use drm_gem_object_unreference()
instead of drm_gem_object_unreference_unlocked().

Found by Linux Driver Verification project (linuxtesting.org).

This regression has been introduced in

commit a8bb6818270c32126dba0fd2ddb139d885c5687d
Author: Daniel Vetter <daniel.vetter at ffwll.ch>
Date:   Mon Feb 10 18:00:39 2014 +0100

    drm/i915: Fix error path leak in fbdev fb allocation

Signed-off-by: Alexey Khoroshilov <khoroshilov at ispras.ru>
Signed-off-by: Daniel Vetter <daniel.vetter at ffwll.ch>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/gpu/drm/i915/intel_display.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index b019c563a787..0d68c70368ff 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -8220,7 +8220,7 @@ __intel_framebuffer_create(struct drm_device *dev,

 	intel_fb = kzalloc(sizeof(*intel_fb), GFP_KERNEL);
 	if (!intel_fb) {
-		drm_gem_object_unreference_unlocked(&obj->base);
+		drm_gem_object_unreference(&obj->base);
 		return ERR_PTR(-ENOMEM);
 	}

@@ -8230,7 +8230,7 @@ __intel_framebuffer_create(struct drm_device *dev,

 	return &intel_fb->base;
 err:
-	drm_gem_object_unreference_unlocked(&obj->base);
+	drm_gem_object_unreference(&obj->base);
 	kfree(intel_fb);

 	return ERR_PTR(ret);