| Message ID | 20220203152305.1846862-1-trix@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | drm/ast: fix using freed memory | expand |
On Thu, Feb 3, 2022 at 7:23 AM <trix@redhat.com> wrote: > > From: Tom Rix <trix@redhat.com> > > clang static analysis reports this problem > ast_mode.c:1235:3: warning: Use of memory after it is freed > drm_connector_update_edid_property(&ast_connector->base, edid); > ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > The second condition on > > if (!flags && ast_connector->i2c) > > Means that the edid is not always set. If the previous block > fails the freed edid value will be used. So set edid to NULL > after freeing. > > Fixes: 55dc449a7c60 ("drm/ast: Handle failed I2C initialization gracefully") > Signed-off-by: Tom Rix <trix@redhat.com> > --- > drivers/gpu/drm/ast/ast_mode.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/drivers/gpu/drm/ast/ast_mode.c b/drivers/gpu/drm/ast/ast_mode.c > index ab52efb15670e..9131dc8a1a2fc 100644 > --- a/drivers/gpu/drm/ast/ast_mode.c > +++ b/drivers/gpu/drm/ast/ast_mode.c > @@ -1224,10 +1224,12 @@ static int ast_get_modes(struct drm_connector *connector) > return -ENOMEM; > > flags = ast_dp501_read_edid(connector->dev, (u8 *)edid); > - if (flags) > + if (flags) { > ast->dp501_maxclk = ast_get_dp501_max_clk(connector->dev); > - else > + } else { > kfree(edid); > + edid = NULL; > + } You probably didn't need to add the {} for the if, but it doesn't really matter. Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> > } > if (!flags && ast_connector->i2c) > edid = drm_get_edid(connector, &ast_connector->i2c->adapter); > -- > 2.26.3 >
Hi Am 03.02.22 um 16:23 schrieb trix@redhat.com: > From: Tom Rix <trix@redhat.com> > > clang static analysis reports this problem > ast_mode.c:1235:3: warning: Use of memory after it is freed > drm_connector_update_edid_property(&ast_connector->base, edid); > ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > The second condition on > > if (!flags && ast_connector->i2c) > > Means that the edid is not always set. If the previous block > fails the freed edid value will be used. So set edid to NULL > after freeing. Thanks for your patch. We have meanwhile merges a change that replaces the code entirely. Best regards Thomas > > Fixes: 55dc449a7c60 ("drm/ast: Handle failed I2C initialization gracefully") > Signed-off-by: Tom Rix <trix@redhat.com> > --- > drivers/gpu/drm/ast/ast_mode.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/drivers/gpu/drm/ast/ast_mode.c b/drivers/gpu/drm/ast/ast_mode.c > index ab52efb15670e..9131dc8a1a2fc 100644 > --- a/drivers/gpu/drm/ast/ast_mode.c > +++ b/drivers/gpu/drm/ast/ast_mode.c > @@ -1224,10 +1224,12 @@ static int ast_get_modes(struct drm_connector *connector) > return -ENOMEM; > > flags = ast_dp501_read_edid(connector->dev, (u8 *)edid); > - if (flags) > + if (flags) { > ast->dp501_maxclk = ast_get_dp501_max_clk(connector->dev); > - else > + } else { > kfree(edid); > + edid = NULL; > + } > } > if (!flags && ast_connector->i2c) > edid = drm_get_edid(connector, &ast_connector->i2c->adapter);
diff --git a/drivers/gpu/drm/ast/ast_mode.c b/drivers/gpu/drm/ast/ast_mode.c index ab52efb15670e..9131dc8a1a2fc 100644 --- a/drivers/gpu/drm/ast/ast_mode.c +++ b/drivers/gpu/drm/ast/ast_mode.c @@ -1224,10 +1224,12 @@ static int ast_get_modes(struct drm_connector *connector) return -ENOMEM; flags = ast_dp501_read_edid(connector->dev, (u8 *)edid); - if (flags) + if (flags) { ast->dp501_maxclk = ast_get_dp501_max_clk(connector->dev); - else + } else { kfree(edid); + edid = NULL; + } } if (!flags && ast_connector->i2c) edid = drm_get_edid(connector, &ast_connector->i2c->adapter);