| Message ID | 20191118130252.170324-1-stephan@gerhold.net (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | drm/mcde: dsi: Fix invalid pointer dereference if panel cannot be found | expand |
On Mon, Nov 18, 2019 at 2:04 PM Stephan Gerhold <stephan@gerhold.net> wrote: > 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> Patch applied and pushed to drm-misc-fixes, thanks! Yours, Linus Walleij
diff --git a/drivers/gpu/drm/mcde/mcde_dsi.c b/drivers/gpu/drm/mcde/mcde_dsi.c index 03896a1f339a..eb3a855aef9a 100644 --- a/drivers/gpu/drm/mcde/mcde_dsi.c +++ b/drivers/gpu/drm/mcde/mcde_dsi.c @@ -924,11 +924,13 @@ 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); }
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> --- drivers/gpu/drm/mcde/mcde_dsi.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)