[3.13.y.z extended stable] Patch "imx-drm: ipuv3-plane: fix ipu_plane_dpms()" has been added to staging queue

[Kamal Mostafa]

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

    imx-drm: ipuv3-plane: fix ipu_plane_dpms()

to the linux-3.13.y-queue branch of the 3.13.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.13.y-queue

This patch is scheduled to be released in version 3.13.11.9.

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

For more information about the 3.13.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From 9980ceea3e25a35356dadf3b4e217b0e7af97bc6 Mon Sep 17 00:00:00 2001
From: Russell King <rmk+kernel at arm.linux.org.uk>
Date: Mon, 1 Sep 2014 18:07:33 +0100
Subject: imx-drm: ipuv3-plane: fix ipu_plane_dpms()

commit 3a44a2058747d71385eb69691c7f977cb58cc293 upstream.

When unbinding imx-drm, the following oops was observed:

Unable to handle kernel NULL pointer dereference at virtual address 00000004
pgd = e995c000
[00000004] *pgd=4fea5831
Internal error: Oops: 817 [#1] SMP ARM
Modules linked in: bnep rfcomm bluetooth nfsd exportfs hid_cypress brcmfmac brcmutil snd_soc_fsl_ssi snd_soc_fsl_spdif imx_pcm_fiq imx_pcm_dma snd_soc_sgtl5000 imx_sdma imx2_wdt imx_ldb(C) imx_thermal snd_soc_imx_sgtl5000 snd_soc_imx_spdif snd_soc_imx_audmux
CPU: 1 PID: 779 Comm: bash Tainted: G         C    3.16.0-rc2+ #1230
task: ea9eb180 ti: ea378000 task.ti: ea378000
PC is at ipu_dp_put+0x10/0x18
LR is at ipu_plane_dpms+0x60/0x8c
pc : [<c0350d20>]    lr : [<c04bd9e8>]    psr: 200f0013
sp : ea379d80  ip : ea379d90  fp : ea379d8c
r10: 00100100  r9 : 00000000  r8 : 00200200
r7 : e9ba0264  r6 : e9ba01f8  r5 : 00000000  r4 : ea34b800
r3 : 00000000  r2 : 00000000  r1 : 0000009b  r0 : 00000000
Flags: nzCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment user
Control: 10c53c7d  Table: 3995c04a  DAC: 00000015
Process bash (pid: 779, stack limit = 0xea378240)
Stack: (0xea379d80 to 0xea37a000)
...
Backtrace:
[<c0350d10>] (ipu_dp_put) from [<c04bd9e8>] (ipu_plane_dpms+0x60/0x8c)
[<c04bd988>] (ipu_plane_dpms) from [<c04bda40>] (ipu_disable_plane+0x2c/0x60)
[<c04bda14>] (ipu_disable_plane) from [<c04bda9c>] (ipu_plane_destroy+0x28/0x60)
[<c04bda74>] (ipu_plane_destroy) from [<c033ff84>] (drm_mode_config_cleanup+0x1b8/0x250)
[<c033fdcc>] (drm_mode_config_cleanup) from [<c04bc234>] (imx_drm_driver_unload+0x44/0x4c)
[<c04bc1f0>] (imx_drm_driver_unload) from [<c03394a4>] (drm_dev_unregister+0x2c/0xa0)
[<c0339478>] (drm_dev_unregister) from [<c0339f8c>] (drm_put_dev+0x30/0x6c)
[<c0339f5c>] (drm_put_dev) from [<c04bc1cc>] (imx_drm_unbind+0x14/0x18)
[<c04bc1b8>] (imx_drm_unbind) from [<c03530b4>] (component_master_del+0xbc/0xd8)
...
Code: e1a0c00d e92dd800 e24cb004 e3a03000 (e5c03004)

This is caused by a missing check in ipu_plane_dpms for a NULL pointer.

Fixes: b8d181e408af ("staging: drm/imx: add drm plane support")
Signed-off-by: Russell King <rmk+kernel at arm.linux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/staging/imx-drm/ipuv3-plane.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/staging/imx-drm/ipuv3-plane.c b/drivers/staging/imx-drm/ipuv3-plane.c
index d97454a..69ed0d9 100644
--- a/drivers/staging/imx-drm/ipuv3-plane.c
+++ b/drivers/staging/imx-drm/ipuv3-plane.c
@@ -269,7 +269,8 @@ static void ipu_plane_dpms(struct ipu_plane *ipu_plane, int mode)

 		ipu_idmac_put(ipu_plane->ipu_ch);
 		ipu_dmfc_put(ipu_plane->dmfc);
-		ipu_dp_put(ipu_plane->dp);
+		if (ipu_plane->dp)
+			ipu_dp_put(ipu_plane->dp);
 	}
 }

--
1.9.1