From mboxrd@z Thu Jan 1 00:00:00 1970 From: rmk+kernel@arm.linux.org.uk (Russell King) Date: Sat, 28 Jun 2014 15:56:20 +0100 Subject: [PATCH 1/2] imx-drm: ipuv3-plane: fix ipu_plane_dpms() In-Reply-To: <20140628145556.GG32514@n2100.arm.linux.org.uk> References: <20140628145556.GG32514@n2100.arm.linux.org.uk> Message-ID: To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org 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 : [] lr : [] 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: [] (ipu_dp_put) from [] (ipu_plane_dpms+0x60/0x8c) [] (ipu_plane_dpms) from [] (ipu_disable_plane+0x2c/0x60) [] (ipu_disable_plane) from [] (ipu_plane_destroy+0x28/0x60) [] (ipu_plane_destroy) from [] (drm_mode_config_cleanup+0x1b8/0x250) [] (drm_mode_config_cleanup) from [] (imx_drm_driver_unload+0x44/0x4c) [] (imx_drm_driver_unload) from [] (drm_dev_unregister+0x2c/0xa0) [] (drm_dev_unregister) from [] (drm_put_dev+0x30/0x6c) [] (drm_put_dev) from [] (imx_drm_unbind+0x14/0x18) [] (imx_drm_unbind) from [] (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. Signed-off-by: Russell King --- 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 6f393a11f44d..50de10a550e9 100644 --- a/drivers/staging/imx-drm/ipuv3-plane.c +++ b/drivers/staging/imx-drm/ipuv3-plane.c @@ -281,7 +281,8 @@ 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); } } -- 1.8.3.1