From: Srinivasan Shanmugam Date: Fri, 6 Feb 2026 15:19:23 +0000 (+0530) Subject: drm/amd/display: Fix out-of-bounds stream encoder index v3 X-Git-Url: http://git.monstr.eu/?a=commitdiff_plain;h=abde491143e4e12eecc41337910aace4e8d59603;p=linux-2.6-microblaze.git drm/amd/display: Fix out-of-bounds stream encoder index v3 eng_id can be negative and that stream_enc_regs[] can be indexed out of bounds. eng_id is used directly as an index into stream_enc_regs[], which has only 5 entries. When eng_id is 5 (ENGINE_ID_DIGF) or negative, this can access memory past the end of the array. Add a bounds check using ARRAY_SIZE() before using eng_id as an index. The unsigned cast also rejects negative values. This avoids out-of-bounds access. Fixes the below smatch error: dcn*_resource.c: stream_encoder_create() may index stream_enc_regs[eng_id] out of bounds (size 5). drivers/gpu/drm/amd/amdgpu/../display/dc/resource/dcn351/dcn351_resource.c 1246 static struct stream_encoder *dcn35_stream_encoder_create( 1247 enum engine_id eng_id, 1248 struct dc_context *ctx) 1249 { ... 1255 1256 /* Mapping of VPG, AFMT, DME register blocks to DIO block instance */ 1257 if (eng_id <= ENGINE_ID_DIGF) { ENGINE_ID_DIGF is 5. should <= be dc_bios, 1283 eng_id, vpg, afmt, --> 1284 &stream_enc_regs[eng_id], ^^^^^^^^^^^^^^^^^^^^^^^ This stream_enc_regs[] array has 5 elements so we are one element beyond the end of the array. ... 1287 return &enc1->base; 1288 } v2: use explicit bounds check as suggested by Roman/Dan; avoid unsigned int cast v3: The compiler already knows how to compare the two values, so the cast (int) is not needed. (Roman) Fixes: 2728e9c7c842 ("drm/amd/display: add DC changes for DCN351") Reported-by: Dan Carpenter Cc: Harry Wentland Cc: Mario Limonciello Cc: Alex Hung Cc: Aurabindo Pillai Cc: ChiaHsuan Chung Cc: Roman Li Signed-off-by: Srinivasan Shanmugam Reviewed-by: Roman Li Signed-off-by: Alex Deucher --- diff --git a/drivers/gpu/drm/amd/display/dc/resource/dcn315/dcn315_resource.c b/drivers/gpu/drm/amd/display/dc/resource/dcn315/dcn315_resource.c index a8283f21008e..3ae787a377b1 100644 --- a/drivers/gpu/drm/amd/display/dc/resource/dcn315/dcn315_resource.c +++ b/drivers/gpu/drm/amd/display/dc/resource/dcn315/dcn315_resource.c @@ -1230,12 +1230,12 @@ static struct stream_encoder *dcn315_stream_encoder_create( /*PHYB is wired off in HW, allow front end to remapping, otherwise needs more changes*/ /* Mapping of VPG, AFMT, DME register blocks to DIO block instance */ - if (eng_id <= ENGINE_ID_DIGF) { - vpg_inst = eng_id; - afmt_inst = eng_id; - } else + if (eng_id < 0 || eng_id >= ARRAY_SIZE(stream_enc_regs)) return NULL; + vpg_inst = eng_id; + afmt_inst = eng_id; + enc1 = kzalloc(sizeof(struct dcn10_stream_encoder), GFP_KERNEL); vpg = dcn31_vpg_create(ctx, vpg_inst); afmt = dcn31_afmt_create(ctx, afmt_inst); diff --git a/drivers/gpu/drm/amd/display/dc/resource/dcn316/dcn316_resource.c b/drivers/gpu/drm/amd/display/dc/resource/dcn316/dcn316_resource.c index 4da0e9320159..4b8668458f03 100644 --- a/drivers/gpu/drm/amd/display/dc/resource/dcn316/dcn316_resource.c +++ b/drivers/gpu/drm/amd/display/dc/resource/dcn316/dcn316_resource.c @@ -1223,12 +1223,12 @@ static struct stream_encoder *dcn316_stream_encoder_create( int afmt_inst; /* Mapping of VPG, AFMT, DME register blocks to DIO block instance */ - if (eng_id <= ENGINE_ID_DIGF) { - vpg_inst = eng_id; - afmt_inst = eng_id; - } else + if (eng_id < 0 || eng_id >= ARRAY_SIZE(stream_enc_regs)) return NULL; + vpg_inst = eng_id; + afmt_inst = eng_id; + enc1 = kzalloc(sizeof(struct dcn10_stream_encoder), GFP_KERNEL); vpg = dcn31_vpg_create(ctx, vpg_inst); afmt = dcn31_afmt_create(ctx, afmt_inst); diff --git a/drivers/gpu/drm/amd/display/dc/resource/dcn32/dcn32_resource.c b/drivers/gpu/drm/amd/display/dc/resource/dcn32/dcn32_resource.c index d3b92c61b7ad..a55078458ba5 100644 --- a/drivers/gpu/drm/amd/display/dc/resource/dcn32/dcn32_resource.c +++ b/drivers/gpu/drm/amd/display/dc/resource/dcn32/dcn32_resource.c @@ -1211,12 +1211,12 @@ static struct stream_encoder *dcn32_stream_encoder_create( int afmt_inst; /* Mapping of VPG, AFMT, DME register blocks to DIO block instance */ - if (eng_id <= ENGINE_ID_DIGF) { - vpg_inst = eng_id; - afmt_inst = eng_id; - } else + if (eng_id < 0 || eng_id >= ARRAY_SIZE(stream_enc_regs)) return NULL; + vpg_inst = eng_id; + afmt_inst = eng_id; + enc1 = kzalloc(sizeof(struct dcn10_stream_encoder), GFP_KERNEL); vpg = dcn32_vpg_create(ctx, vpg_inst); afmt = dcn32_afmt_create(ctx, afmt_inst); diff --git a/drivers/gpu/drm/amd/display/dc/resource/dcn321/dcn321_resource.c b/drivers/gpu/drm/amd/display/dc/resource/dcn321/dcn321_resource.c index d08691ea27ea..188c3f24f110 100644 --- a/drivers/gpu/drm/amd/display/dc/resource/dcn321/dcn321_resource.c +++ b/drivers/gpu/drm/amd/display/dc/resource/dcn321/dcn321_resource.c @@ -1192,12 +1192,12 @@ static struct stream_encoder *dcn321_stream_encoder_create( int afmt_inst; /* Mapping of VPG, AFMT, DME register blocks to DIO block instance */ - if (eng_id <= ENGINE_ID_DIGF) { - vpg_inst = eng_id; - afmt_inst = eng_id; - } else + if (eng_id < 0 || eng_id >= ARRAY_SIZE(stream_enc_regs)) return NULL; + vpg_inst = eng_id; + afmt_inst = eng_id; + enc1 = kzalloc(sizeof(struct dcn10_stream_encoder), GFP_KERNEL); vpg = dcn321_vpg_create(ctx, vpg_inst); afmt = dcn321_afmt_create(ctx, afmt_inst); diff --git a/drivers/gpu/drm/amd/display/dc/resource/dcn35/dcn35_resource.c b/drivers/gpu/drm/amd/display/dc/resource/dcn35/dcn35_resource.c index 945da8cffada..5ea805fcff48 100644 --- a/drivers/gpu/drm/amd/display/dc/resource/dcn35/dcn35_resource.c +++ b/drivers/gpu/drm/amd/display/dc/resource/dcn35/dcn35_resource.c @@ -1274,12 +1274,12 @@ static struct stream_encoder *dcn35_stream_encoder_create( int afmt_inst; /* Mapping of VPG, AFMT, DME register blocks to DIO block instance */ - if (eng_id <= ENGINE_ID_DIGF) { - vpg_inst = eng_id; - afmt_inst = eng_id; - } else + if (eng_id < 0 || eng_id >= ARRAY_SIZE(stream_enc_regs)) return NULL; + vpg_inst = eng_id; + afmt_inst = eng_id; + enc1 = kzalloc(sizeof(struct dcn10_stream_encoder), GFP_KERNEL); vpg = dcn31_vpg_create(ctx, vpg_inst); afmt = dcn31_afmt_create(ctx, afmt_inst); diff --git a/drivers/gpu/drm/amd/display/dc/resource/dcn351/dcn351_resource.c b/drivers/gpu/drm/amd/display/dc/resource/dcn351/dcn351_resource.c index e660889904a9..424b52e2dd7b 100644 --- a/drivers/gpu/drm/amd/display/dc/resource/dcn351/dcn351_resource.c +++ b/drivers/gpu/drm/amd/display/dc/resource/dcn351/dcn351_resource.c @@ -1254,12 +1254,12 @@ static struct stream_encoder *dcn35_stream_encoder_create( int afmt_inst; /* Mapping of VPG, AFMT, DME register blocks to DIO block instance */ - if (eng_id <= ENGINE_ID_DIGF) { - vpg_inst = eng_id; - afmt_inst = eng_id; - } else + if (eng_id < 0 || eng_id >= ARRAY_SIZE(stream_enc_regs)) return NULL; + vpg_inst = eng_id; + afmt_inst = eng_id; + enc1 = kzalloc(sizeof(struct dcn10_stream_encoder), GFP_KERNEL); vpg = dcn31_vpg_create(ctx, vpg_inst); afmt = dcn31_afmt_create(ctx, afmt_inst);