[PATCH 3.13 039/163] imx-drm: ipuv3-plane: fix ipu_plane_dpms()

From: Kamal Mostafa
Date: Thu Oct 09 2014 - 17:42:36 EST -stable review patch. If anyone has any objections, please let me know.


From: Russell King <rmk+kernel@xxxxxxxxxxxxxxxx>

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)
[<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@xxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Kamal Mostafa <kamal@xxxxxxxxxxxxx>
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_dp_put(ipu_plane->dp);
+ if (ipu_plane->dp)
+ ipu_dp_put(ipu_plane->dp);


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