Hi Anitha, On Tue, Jul 27, 2021 at 05:31:24PM -0700, Anitha Chrisanthus wrote: > If kmb_dsi_init() fails the "kmb->kmb_dsi" variable is an error pointer. > This can potentially result in kernel panic when kmb_dsi_host_unregister is > called. > > Fixes: 7f7b96a8a0a1 ("drm/kmb: Add support for KeemBay Display") > Fixes: 98521f4d4b4c ("drm/kmb: Mipi DSI part of the display driver") > Cc: Dan Carpenter <dan.carpenter@xxxxxxxxxx> > Signed-off-by: Anitha Chrisanthus <anitha.chrisanthus@xxxxxxxxx> > --- > drivers/gpu/drm/kmb/kmb_drv.c | 9 ++++++--- > drivers/gpu/drm/kmb/kmb_dsi.c | 9 +++++---- > drivers/gpu/drm/kmb/kmb_dsi.h | 3 ++- > 3 files changed, 13 insertions(+), 8 deletions(-) > > diff --git a/drivers/gpu/drm/kmb/kmb_drv.c b/drivers/gpu/drm/kmb/kmb_drv.c > index bb7eca9e13ae..12f35c43d838 100644 > --- a/drivers/gpu/drm/kmb/kmb_drv.c > +++ b/drivers/gpu/drm/kmb/kmb_drv.c > @@ -454,8 +454,9 @@ static int kmb_remove(struct platform_device *pdev) > dev_set_drvdata(dev, NULL); > > /* Unregister DSI host */ > - kmb_dsi_host_unregister(kmb->kmb_dsi); > + kmb_dsi_host_unregister(); > drm_atomic_helper_shutdown(drm); > + drm_dev_put(drm); > return 0; > } > > @@ -519,7 +520,7 @@ static int kmb_probe(struct platform_device *pdev) > if (IS_ERR(kmb->kmb_dsi)) { > drm_err(&kmb->drm, "failed to initialize DSI\n"); > ret = PTR_ERR(kmb->kmb_dsi); > - goto err_free1; > + goto err_free2; > } > > kmb->kmb_dsi->dev = &dsi_pdev->dev; > @@ -555,8 +556,10 @@ static int kmb_probe(struct platform_device *pdev) > drm_crtc_cleanup(&kmb->crtc); > drm_mode_config_cleanup(&kmb->drm); > err_free1: > + kmb_dsi_clk_disable(kmb->kmb_dsi); > + err_free2: > dev_set_drvdata(dev, NULL); > - kmb_dsi_host_unregister(kmb->kmb_dsi); > + kmb_dsi_host_unregister(); > This really looks like a step backward. There should not be a eed to call unregister if kmb_dsi is not a valid pointer in the first place. Also drn_dev_put() should not be needed with the use of drmm infrastructure. > return ret; > } > diff --git a/drivers/gpu/drm/kmb/kmb_dsi.c b/drivers/gpu/drm/kmb/kmb_dsi.c > index 1cca0fe6f35f..a500172ada87 100644 > --- a/drivers/gpu/drm/kmb/kmb_dsi.c > +++ b/drivers/gpu/drm/kmb/kmb_dsi.c > @@ -172,17 +172,17 @@ mipi_hs_freq_range[MIPI_DPHY_DEFAULT_BIT_RATES] = { > {.default_bit_rate_mbps = 2500, .hsfreqrange_code = 0x49} > }; > > -static void kmb_dsi_clk_disable(struct kmb_dsi *kmb_dsi) > +void kmb_dsi_clk_disable(struct kmb_dsi *kmb_dsi) > { > clk_disable_unprepare(kmb_dsi->clk_mipi); > clk_disable_unprepare(kmb_dsi->clk_mipi_ecfg); > clk_disable_unprepare(kmb_dsi->clk_mipi_cfg); > } > > -void kmb_dsi_host_unregister(struct kmb_dsi *kmb_dsi) > +void kmb_dsi_host_unregister(void) > { > - kmb_dsi_clk_disable(kmb_dsi); > - mipi_dsi_host_unregister(kmb_dsi->host); > + if (dsi_host) > + mipi_dsi_host_unregister(dsi_host); > } I thought we had killed the global dsi_host variable?? Seems some cleanup is till needed here. Sam