From: Stephan Gerhold stephan@gerhold.net
[ Upstream commit c131280c03bd1c225c2e64e9ef75873ffca3d96e ]
The "panel" pointer is not reset to NULL if of_drm_find_panel() returns an error. Therefore we later assume that a panel was found, and try to dereference the error pointer, resulting in:
mcde-dsi a0351000.dsi: failed to find panel try bridge (4294966779) Unable to handle kernel paging request at virtual address fffffe03 PC is at drm_panel_bridge_add.part.0+0x10/0x5c LR is at mcde_dsi_bind+0x120/0x464 ...
Reset "panel" to NULL to avoid this problem. Also change the format string of the error to %ld to print the negative errors correctly. The crash above then becomes:
mcde-dsi a0351000.dsi: failed to find panel try bridge (-517) mcde-dsi a0351000.dsi: no panel or bridge ...
Fixes: 5fc537bfd000 ("drm/mcde: Add new driver for ST-Ericsson MCDE") Signed-off-by: Stephan Gerhold stephan@gerhold.net Signed-off-by: Linus Walleij linus.walleij@linaro.org Link: https://patchwork.freedesktop.org/patch/msgid/20191118130252.170324-1-stepha... Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/gpu/drm/mcde/mcde_dsi.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/mcde/mcde_dsi.c b/drivers/gpu/drm/mcde/mcde_dsi.c index f9c9e32b299c..35bb825d1918 100644 --- a/drivers/gpu/drm/mcde/mcde_dsi.c +++ b/drivers/gpu/drm/mcde/mcde_dsi.c @@ -935,11 +935,13 @@ static int mcde_dsi_bind(struct device *dev, struct device *master, for_each_available_child_of_node(dev->of_node, child) { panel = of_drm_find_panel(child); if (IS_ERR(panel)) { - dev_err(dev, "failed to find panel try bridge (%lu)\n", + dev_err(dev, "failed to find panel try bridge (%ld)\n", PTR_ERR(panel)); + panel = NULL; + bridge = of_drm_find_bridge(child); if (IS_ERR(bridge)) { - dev_err(dev, "failed to find bridge (%lu)\n", + dev_err(dev, "failed to find bridge (%ld)\n", PTR_ERR(bridge)); return PTR_ERR(bridge); }