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drm: mxsfb: Fix NULL pointer dereference crash on unload

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commit 3cfc183052c3dbf8eae57b6c1685dab00ed3db4a upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Marek Vasut 2021-10-16 23:04:46 +02:00 committed by Greg Kroah-Hartman
parent 96835b68d7
commit f40c2281d2
1 changed files with 5 additions and 1 deletions
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6
drivers/gpu/drm/mxsfb/mxsfb_drv.c
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@ -268,7 +268,11 @@ 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);
}