| Message ID | 20240412083532.11540-1-amishin@t-argos.ru (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2] drm: bridge: cdns-mhdp8546: Fix possible null pointer dereference | expand |
Hey Aleksandr, On Fri, Apr 12, 2024 at 10:40 AM Aleksandr Mishin <amishin@t-argos.ru> wrote: > > In cdns_mhdp_atomic_enable(), the return value of drm_mode_duplicate() is > assigned to mhdp_state->current_mode, and there is a dereference of it in > drm_mode_set_name(), which will lead to a NULL pointer dereference on > failure of drm_mode_duplicate(). > > Fix this bug by adding a check of mhdp_state->current_mode. > > Fixes: fb43aa0acdfd ("drm: bridge: Add support for Cadence MHDP8546 DPI/DP bridge") > Signed-off-by: Aleksandr Mishin <amishin@t-argos.ru> > --- > v2: Fix a mistake where the mutex remained locked > > drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c > index e226acc5c15e..5b831d6d7764 100644 > --- a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c > +++ b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c > @@ -2059,6 +2059,11 @@ static void cdns_mhdp_atomic_enable(struct drm_bridge *bridge, > mhdp_state = to_cdns_mhdp_bridge_state(new_state); > > mhdp_state->current_mode = drm_mode_duplicate(bridge->dev, mode); > + if (!mhdp_state->current_mode) { > + ret = -EINVAL; > + goto out; > + } > + This chunk no longer applies on drm-misc-next. I think the approach here is still better than what is in drm-misc-next since it unlocks link_mutex. Can you rebase + reword the commit message and send that out as v3? > drm_mode_set_name(mhdp_state->current_mode); > > dev_dbg(mhdp->dev, "%s: Enabling mode %s\n", __func__, mode->name); > -- > 2.30.2 >
diff --git a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c index e226acc5c15e..5b831d6d7764 100644 --- a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c +++ b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c @@ -2059,6 +2059,11 @@ static void cdns_mhdp_atomic_enable(struct drm_bridge *bridge, mhdp_state = to_cdns_mhdp_bridge_state(new_state); mhdp_state->current_mode = drm_mode_duplicate(bridge->dev, mode); + if (!mhdp_state->current_mode) { + ret = -EINVAL; + goto out; + } + drm_mode_set_name(mhdp_state->current_mode); dev_dbg(mhdp->dev, "%s: Enabling mode %s\n", __func__, mode->name);
In cdns_mhdp_atomic_enable(), the return value of drm_mode_duplicate() is assigned to mhdp_state->current_mode, and there is a dereference of it in drm_mode_set_name(), which will lead to a NULL pointer dereference on failure of drm_mode_duplicate(). Fix this bug by adding a check of mhdp_state->current_mode. Fixes: fb43aa0acdfd ("drm: bridge: Add support for Cadence MHDP8546 DPI/DP bridge") Signed-off-by: Aleksandr Mishin <amishin@t-argos.ru> --- v2: Fix a mistake where the mutex remained locked drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c | 5 +++++ 1 file changed, 5 insertions(+)