On Tue, 13 Oct 2026, Arnd Bergmann <[email protected]> wrote: > From: Arnd Bergmann <[email protected]> > > The drm_parse_cea_ext() calls into nine individual parser functions > based on the data format. If all of those get inlined and KASAN_STACK > is enabled, this can explode the combined stack usage beyond a > reasonable amount: > > drivers/gpu/drm/drm_edid.c: In function 'update_display_info': > drivers/gpu/drm/drm_edid.c:7040:1: error: the frame size of 1888 bytes is > larger than 1536 bytes [-Werror=frame-larger-than=] > 7040 | } > | ^ > > Mark all of the individual parser functions as noinline_for_stack > to avoid this and keep their stack frames separate. This reduces > the stack usage for update_display_info/drm_parse_cea_ext to > a more manageable 744 bytes, while each parser only adds at most > 200 bytes on top.
Is there really no way to tell the compiler to not do silly things in a more generic way? BR, Jani. > > Signed-off-by: Arnd Bergmann <[email protected]> > --- > drivers/gpu/drm/drm_edid.c | 31 +++++++++++++++++-------------- > 1 file changed, 17 insertions(+), 14 deletions(-) > > diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c > index 3148038747b6..913a8bbe8894 100644 > --- a/drivers/gpu/drm/drm_edid.c > +++ b/drivers/gpu/drm/drm_edid.c > @@ -5341,8 +5341,9 @@ static int edid_hfeeodb_extension_block_count(const > struct edid *edid) > * etc). For example, if the bit 0 in bitmap is set, first mode in VDB can > * support YCBCR420 output too. > */ > -static void parse_cta_y420cmdb(struct drm_connector *connector, > - const struct cea_db *db, u64 *y420cmdb_map) > +static noinline_for_stack void > +parse_cta_y420cmdb(struct drm_connector *connector, const struct cea_db *db, > + u64 *y420cmdb_map) > { > struct drm_display_info *info = &connector->display_info; > int i, map_len = cea_db_payload_len(db) - 1; > @@ -5515,7 +5516,7 @@ static uint8_t hdr_metadata_type(const u8 *edid_ext) > BIT(HDMI_STATIC_METADATA_TYPE1); > } > > -static void > +static noinline_for_stack void > drm_parse_hdr_metadata_block(struct drm_connector *connector, const u8 *db) > { > struct hdr_static_metadata *hdr_metadata = > @@ -6070,7 +6071,8 @@ drm_default_rgb_quant_range(const struct > drm_display_mode *mode) > EXPORT_SYMBOL(drm_default_rgb_quant_range); > > /* CTA-861 Video Data Block (CTA VDB) */ > -static void parse_cta_vdb(struct drm_connector *connector, const struct > cea_db *db) > +static noinline_for_stack void > +parse_cta_vdb(struct drm_connector *connector, const struct cea_db *db) > { > struct drm_display_info *info = &connector->display_info; > int i, vic_index, len = cea_db_payload_len(db); > @@ -6136,8 +6138,8 @@ static bool cta_vdb_has_vic(const struct drm_connector > *connector, u8 vic) > } > > /* CTA-861-H YCbCr 4:2:0 Video Data Block (CTA Y420VDB) */ > -static void parse_cta_y420vdb(struct drm_connector *connector, > - const struct cea_db *db) > +static noinline_for_stack void > +parse_cta_y420vdb(struct drm_connector *connector, const struct cea_db *db) > { > struct drm_display_info *info = &connector->display_info; > struct drm_hdmi_info *hdmi = &info->hdmi; > @@ -6155,7 +6157,8 @@ static void parse_cta_y420vdb(struct drm_connector > *connector, > } > } > > -static void drm_parse_vcdb(struct drm_connector *connector, const u8 *db) > +static noinline_for_stack void > +drm_parse_vcdb(struct drm_connector *connector, const u8 *db) > { > struct drm_display_info *info = &connector->display_info; > > @@ -6310,8 +6313,8 @@ static void drm_parse_dsc_info(struct drm_hdmi_dsc_cap > *hdmi_dsc, > } > > /* Sink Capability Data Structure */ > -static void drm_parse_hdmi_forum_scds(struct drm_connector *connector, > - const u8 *hf_scds) > +static noinline_for_stack void > +drm_parse_hdmi_forum_scds(struct drm_connector *connector, const u8 *hf_scds) > { > struct drm_display_info *info = &connector->display_info; > struct drm_hdmi_info *hdmi = &info->hdmi; > @@ -6451,7 +6454,7 @@ static void drm_parse_hdmi_deep_color_info(struct > drm_connector *connector, > } > > /* HDMI Vendor-Specific Data Block (HDMI VSDB, H14b-VSDB) */ > -static void > +static noinline_for_stack void > drm_parse_hdmi_vsdb_video(struct drm_connector *connector, const u8 *db) > { > struct drm_display_info *info = &connector->display_info; > @@ -6486,8 +6489,8 @@ drm_parse_hdmi_vsdb_video(struct drm_connector > *connector, const u8 *db) > * See EDID extension for head-mounted and specialized monitors, specified > at: > * > https://docs.microsoft.com/en-us/windows-hardware/drivers/display/specialized-monitors-edid-extension > */ > -static void drm_parse_microsoft_vsdb(struct drm_connector *connector, > - const u8 *db) > +static noinline_for_stack void > +drm_parse_microsoft_vsdb(struct drm_connector *connector, const u8 *db) > { > struct drm_display_info *info = &connector->display_info; > u8 version = db[4]; > @@ -6558,8 +6561,8 @@ static void drm_parse_amd_vsdb_v3(struct > drm_display_info *info, > info->amd_vsdb.max_frame_rate = max_frame_rate; > } > > -static void drm_parse_amd_vsdb(struct drm_connector *connector, > - const struct cea_db *db) > +static noinline_for_stack void > +drm_parse_amd_vsdb(struct drm_connector *connector, const struct cea_db *db) > { > struct drm_display_info *info = &connector->display_info; > const u8 *data = cea_db_data(db); -- Jani Nikula, Intel
