| Message ID | 20220613163705.1531721-1-nfraprado@collabora.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | drm/bridge: anx7625: Zero error variable when panel bridge not present | expand |
On Mon, Jun 13, 2022 at 12:37:05PM -0400, Nícolas F. R. A. Prado wrote: > While parsing the DT, the anx7625 driver checks for the presence of a > panel bridge on endpoint 1. If it is missing, pdata->panel_bridge stores > the error pointer and the function returns successfully without first > cleaning that variable. This is an issue since other functions later > check for the presence of a panel bridge by testing the trueness of that > variable. > > In order to ensure proper behavior, zero out pdata->panel_bridge before > returning when no panel bridge is found. > > Fixes: 9e82ea0fb1df ("drm/bridge: anx7625: switch to devm_drm_of_get_bridge") > Signed-off-by: Nícolas F. R. A. Prado <nfraprado@collabora.com> > > --- > > drivers/gpu/drm/bridge/analogix/anx7625.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/bridge/analogix/anx7625.c b/drivers/gpu/drm/bridge/analogix/anx7625.c > index 53a5da6c49dd..3aed4de16690 100644 > --- a/drivers/gpu/drm/bridge/analogix/anx7625.c > +++ b/drivers/gpu/drm/bridge/analogix/anx7625.c > @@ -1657,8 +1657,10 @@ static int anx7625_parse_dt(struct device *dev, > > pdata->panel_bridge = devm_drm_of_get_bridge(dev, np, 1, 0); > if (IS_ERR(pdata->panel_bridge)) { > - if (PTR_ERR(pdata->panel_bridge) == -ENODEV) > + if (PTR_ERR(pdata->panel_bridge) == -ENODEV) { > + pdata->panel_bridge = NULL; > return 0; > + } > > return PTR_ERR(pdata->panel_bridge); > } > -- > 2.36.1 > Thanks for spotting this error Nícolas. As you mentioned, prior to 9e82ea0fb1df the "pdata->panel_bridge" pointer was not modified (i.e. left to NULL) on the ENODEV error branch. I missed it during the refactor, sorry about that.
Il 13/06/22 18:37, Nícolas F. R. A. Prado ha scritto: > While parsing the DT, the anx7625 driver checks for the presence of a > panel bridge on endpoint 1. If it is missing, pdata->panel_bridge stores > the error pointer and the function returns successfully without first > cleaning that variable. This is an issue since other functions later > check for the presence of a panel bridge by testing the trueness of that > variable. > > In order to ensure proper behavior, zero out pdata->panel_bridge before > returning when no panel bridge is found. > > Fixes: 9e82ea0fb1df ("drm/bridge: anx7625: switch to devm_drm_of_get_bridge") > Signed-off-by: Nícolas F. R. A. Prado <nfraprado@collabora.com> > I would've preferred s/zero out/cleanup/g but it's also fine as you wrote it. Besides, good catch! Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
On Tue, 14 Jun 2022 at 09:52, AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com> wrote: > > Il 13/06/22 18:37, Nícolas F. R. A. Prado ha scritto: > > While parsing the DT, the anx7625 driver checks for the presence of a > > panel bridge on endpoint 1. If it is missing, pdata->panel_bridge stores > > the error pointer and the function returns successfully without first > > cleaning that variable. This is an issue since other functions later > > check for the presence of a panel bridge by testing the trueness of that > > variable. > > > > In order to ensure proper behavior, zero out pdata->panel_bridge before > > returning when no panel bridge is found. > > > > Fixes: 9e82ea0fb1df ("drm/bridge: anx7625: switch to devm_drm_of_get_bridge") > > Signed-off-by: Nícolas F. R. A. Prado <nfraprado@collabora.com> > > > > I would've preferred s/zero out/cleanup/g but it's also fine as you wrote it. > Besides, good catch! > > Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com> > Applied to drm-misc-next
diff --git a/drivers/gpu/drm/bridge/analogix/anx7625.c b/drivers/gpu/drm/bridge/analogix/anx7625.c index 53a5da6c49dd..3aed4de16690 100644 --- a/drivers/gpu/drm/bridge/analogix/anx7625.c +++ b/drivers/gpu/drm/bridge/analogix/anx7625.c @@ -1657,8 +1657,10 @@ static int anx7625_parse_dt(struct device *dev, pdata->panel_bridge = devm_drm_of_get_bridge(dev, np, 1, 0); if (IS_ERR(pdata->panel_bridge)) { - if (PTR_ERR(pdata->panel_bridge) == -ENODEV) + if (PTR_ERR(pdata->panel_bridge) == -ENODEV) { + pdata->panel_bridge = NULL; return 0; + } return PTR_ERR(pdata->panel_bridge); }
While parsing the DT, the anx7625 driver checks for the presence of a panel bridge on endpoint 1. If it is missing, pdata->panel_bridge stores the error pointer and the function returns successfully without first cleaning that variable. This is an issue since other functions later check for the presence of a panel bridge by testing the trueness of that variable. In order to ensure proper behavior, zero out pdata->panel_bridge before returning when no panel bridge is found. Fixes: 9e82ea0fb1df ("drm/bridge: anx7625: switch to devm_drm_of_get_bridge") Signed-off-by: Nícolas F. R. A. Prado <nfraprado@collabora.com> --- drivers/gpu/drm/bridge/analogix/anx7625.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)