From 7a09b137d3f7c6cc5771ffb9584b22394edc5033 Mon Sep 17 00:00:00 2001
From: Marek Vasut <marex@denx.de>
Date: Sat, 16 Oct 2021 23:04:46 +0200
Subject: drm: mxsfb: Fix NULL pointer dereference crash on unload
Git-commit: 3cfc183052c3dbf8eae57b6c1685dab00ed3db4a
Patch-mainline: v5.15-rc7
References: jsc#PED-1166 jsc#PED-1168 jsc#PED-1170 jsc#PED-1218 jsc#PED-1220 jsc#PED-1222 jsc#PED-1223 jsc#PED-1225
The mxsfb->crtc.funcs may already be NULL when unloading the driver,
in which case calling mxsfb_irq_disable() via drm_irq_uninstall() from
mxsfb_unload() leads to NULL pointer dereference.
Since all we care about is masking the IRQ and mxsfb->base is still
valid, just use that to clear and mask the IRQ.
Fixes: ae1ed00932819 ("drm: mxsfb: Stop using DRM simple display pipeline helper")
Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Daniel Abrecht <public@danielabrecht.ch>
Cc: Emil Velikov <emil.l.velikov@gmail.com>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Stefan Agner <stefan@agner.ch>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20211016210446.171616-1-marex@denx.de
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Acked-by: Patrik Jakobsson <pjakobsson@suse.de>
---
drivers/gpu/drm/mxsfb/mxsfb_drv.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/mxsfb/mxsfb_drv.c b/drivers/gpu/drm/mxsfb/mxsfb_drv.c
index ec0432fe1bdf..86d78634a979 100644
--- a/drivers/gpu/drm/mxsfb/mxsfb_drv.c
+++ b/drivers/gpu/drm/mxsfb/mxsfb_drv.c
@@ -173,7 +173,11 @@ static void mxsfb_irq_disable(struct drm_device *drm)
struct mxsfb_drm_private *mxsfb = drm->dev_private;
mxsfb_enable_axi_clk(mxsfb);
- mxsfb->crtc.funcs->disable_vblank(&mxsfb->crtc);
+
+ /* Disable and clear VBLANK IRQ */
+ writel(CTRL1_CUR_FRAME_DONE_IRQ_EN, mxsfb->base + LCDC_CTRL1 + REG_CLR);
+ writel(CTRL1_CUR_FRAME_DONE_IRQ, mxsfb->base + LCDC_CTRL1 + REG_CLR);
+
mxsfb_disable_axi_clk(mxsfb);
}
--
2.38.1