kernel/linux.git/drivers/gpu/drm/amd/display/dc, branch v5.15.215

drm/amd/display: Bound VBIOS record-chain walk loops

2026-07-04T11:39:36+00:00

[ Upstream commit ff287df16a1a58aca78b08d1f3ee09fc44da0351 ] [Why & How] All record-chain walk loops in bios_parser.c and bios_parser2.c use for(;;) and only terminate on a 0xFF record_type sentinel or zero record_size. A malformed VBIOS image missing the terminator record causes unbounded iteration at probe time, potentially hundreds of thousands of iterations with record_size=1. In the final iterations near the BIOS image boundary, struct casts beyond the 2-byte header validated by GET_IMAGE can also read out of bounds. Cap all 14 record-chain walk loops to BIOS_MAX_NUM_RECORD (256) iterations. The atombios.h defines up to 22 distinct record types and atomfirmware.h has 13. Assuming an average of less than 10 records per type (which is reasonable since most are connector- based) 256 is a generous upper bound. Fixes: 4562236b3bc0 ("drm/amd/dc: Add dc display driver (v2)") Assisted-by: Copilot:claude-opus-4.6 Mythos Reviewed-by: Alex Hung Signed-off-by: Harry Wentland Signed-off-by: Ray Wu Tested-by: Daniel Wheeler Signed-off-by: Alex Deucher (cherry picked from commit 95700a3d660287ed657d6892f7be9ffc0e294a93) Cc: stable@vger.kernel.org Signed-off-by: Sasha Levin

drm/amd/display: Use krealloc_array() in dal_vector_reserve()

2026-06-19T11:33:39+00:00

commit da48bc4461b8a5ebfb9264c9b191a701d8e99009 upstream. [Why & How] dal_vector_reserve() computes the allocation size as "capacity * vector->struct_size" using uint32_t arithmetic, which can silently wrap to a small value on overflow. This would cause krealloc to return a smaller buffer than expected, leading to heap overflows on subsequent vector appends. Replace krealloc() with krealloc_array() which performs an internal overflow check and returns NULL on wrap, preventing the issue. Fixes: 2004f45ef83f ("drm/amd/display: Use kernel alloc/free") Assisted-by: Copilot:claude-opus-4.6 Reviewed-by: Alex Hung Signed-off-by: Harry Wentland Signed-off-by: Ray Wu Tested-by: Daniel Wheeler Signed-off-by: Alex Deucher (cherry picked from commit 37668568641ccc4cc1dbca4923d0a16609dd5707) Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman

drm/amd/display: Clamp VBIOS HDMI retimer register count to array size

2026-06-19T11:33:39+00:00

commit fb0707ce00eef4e2d60c3020e1c0432739703e4a upstream. [Why & How] The VBIOS integrated info tables (v1_11 and v2_1) contain HdmiRegNum and Hdmi6GRegNum fields that are used as loop bounds when copying retimer I2C register settings into fixed-size arrays (dp*_ext_hdmi_reg_settings[9] and dp*_ext_hdmi_6g_reg_settings[3]). These u8 fields are not validated before use, so a malformed VBIOS can specify values up to 255, causing an out-of-bounds heap write during driver probe. Clamp each register count to the destination array size using min_t() before the copy loops, in both get_integrated_info_v11() and get_integrated_info_v2_1(). Assisted-by: GitHub Copilot:claude-opus-4.6 Reviewed-by: Alex Hung Signed-off-by: Harry Wentland Signed-off-by: Ray Wu Tested-by: Daniel Wheeler Signed-off-by: Alex Deucher (cherry picked from commit 5a7f0ef90195940c54b0f5bb85b87da55f038c69) Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman

drm/amd/display: Reject gpio_bitshift >= 32 in bios_parser_get_gpio_pin_info()

2026-06-19T11:33:37+00:00

commit 49c3da65961fe9857c831d47fa1989084e87514a upstream. [Why & How] gpio_bitshift is a uint8_t read directly from the VBIOS GPIO pin table. If the value is >= 32, the expression "1 << gpio_bitshift" triggers undefined behaviour in C (shift count exceeds type width). On x86 the shift is silently masked to 5 bits, producing an incorrect GPIO mask that may cause wrong MMIO register bits to be toggled. Validate gpio_bitshift before use and return BP_RESULT_BADBIOSTABLE for out-of-range values. Fixes: ae79c310b1a6 ("drm/amd/display: Add DCE12 bios parser support") Assisted-by: Copilot:claude-opus-4.6 Reviewed-by: Alex Hung Signed-off-by: Harry Wentland Signed-off-by: Ray Wu Tested-by: Daniel Wheeler Signed-off-by: Alex Deucher (cherry picked from commit eadf438ab8d370b9d19acee9359918c85afeb80d) Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman

drm/amd/display: Validate payload length and link_index in dc_process_dmub_aux_transfer_async

2026-06-01T15:35:48+00:00

commit 6c92f6d9600efa3ef0d9e560a2b52776d9803c29 upstream. [Why&How] dc_process_dmub_aux_transfer_async() copies payload->length bytes into a 16-byte stack buffer (dpaux.data[16]) guarded only by an ASSERT(), which is a no-op in release builds. If a caller ever passes length > 16 this results in a stack buffer overflow via memcpy. Additionally, link_index is used to dereference dc->links[] without bounds checking against dc->link_count, risking an out-of-bounds access. Replace the ASSERT with a hard runtime check that returns false when payload->length exceeds the destination buffer size, and add a bounds check for link_index before it is used. Assisted-by: GitHub Copilot:Claude claude-4-opus Reviewed-by: Alex Hung Signed-off-by: Harry Wentland Signed-off-by: Ivan Lipski Tested-by: Dan Wheeler Signed-off-by: Alex Deucher (cherry picked from commit ba4caa9fecdf7a38f98c878ad05a8a64148b6881) Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman

drm/amd/display: Fix integer overflow in bios_get_image()

2026-06-01T15:35:48+00:00

commit cd86529ec61474a38c3837fb7823790a7c3f8cce upstream. [Why&How] The bounds check in bios_get_image() computes 'offset + size' using unsigned 32-bit arithmetic before comparing against bios_size. If a VBIOS image contains a near-UINT32_MAX offset the addition wraps to a small value, the comparison passes, and the function returns a wild pointer past the VBIOS mapping. Additionally, the comparison uses '<' (strict), which incorrectly rejects the valid exact-fit case where offset + size == bios_size. Fix both issues by restructuring the check to avoid the addition entirely: first reject if offset alone exceeds bios_size, then check size against the remaining space (bios_size - offset). This eliminates the overflow and correctly permits exact-fit accesses. Assisted-by: GitHub Copilot:claude-opus-4.6 Reviewed-by: Alex Hung Signed-off-by: Harry Wentland Signed-off-by: Ivan Lipski Tested-by: Dan Wheeler Signed-off-by: Alex Deucher (cherry picked from commit d40fb392af659c4a02b560319f226842f6ec1a95) Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman

drm/amd/display: Read EDID from VBIOS embedded panel info

2026-06-01T15:35:43+00:00

[ Upstream commit 9ea16f64189bf7b6ba50fc7f0325b3c1f836d105 ] Some board manufacturers hardcode the EDID for the embedded panel in the VBIOS. This EDID should be used when the panel doesn't have a DDC. For reference, see the legacy non-DC display code: amdgpu_atombios_encoder_get_lcd_info() This is necessary to support embedded connectors without DDC. Fixes: 4562236b3bc0 ("drm/amd/dc: Add dc display driver (v2)") Link: https://gitlab.freedesktop.org/drm/amd/-/work_items/5192 Signed-off-by: Timur Kristóf Signed-off-by: Alex Deucher (cherry picked from commit eb105e63b474c11ef6a84a1c6b18100d851ff364) Signed-off-by: Sasha Levin

drm/amd/display: Allow DCE link encoder without AUX registers

2026-06-01T15:35:43+00:00

[ Upstream commit ac27e3f99035f132f23bc0409d0e57f11f054c70 ] Allow constructing the DCE link encoder without DDC, which means the AUX registers array will be NULL. This is necessary to support embedded connectors without DDC. Fixes: 4562236b3bc0 ("drm/amd/dc: Add dc display driver (v2)") Link: https://gitlab.freedesktop.org/drm/amd/-/work_items/5192 Signed-off-by: Timur Kristóf Signed-off-by: Alex Deucher (cherry picked from commit 87f30b101af62590faf6020d106da07efdda199b) Signed-off-by: Sasha Levin

drm/amd/display: Use GFP_ATOMIC in dc_create_stream_for_sink

2026-04-18T08:33:19+00:00

[ Upstream commit 28dfe4317541e57fe52f9a290394cd29c348228b ] This can be called while preemption is disabled, for example by dcn32_internal_validate_bw which is called with the FPU active. Fixes "BUG: scheduling while atomic" messages I encounter on my Navi31 machine. Signed-off-by: Natalie Vock Signed-off-by: Alex Deucher (cherry picked from commit b42dae2ebc5c84a68de63ec4ffdfec49362d53f1) Cc: stable@vger.kernel.org [ Context ] Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

drm/amd/display: Use GFP_ATOMIC in dc_create_plane_state()

2026-01-19T12:09:54+00:00

commit 3c41114dcdabb7b25f5bc33273c6db9c7af7f4a7 upstream. This can get called from an atomic context. Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/4470 Reviewed-by: Harry Wentland Signed-off-by: Alex Deucher (cherry picked from commit 8acdad9344cc7b4e7bc01f0dfea80093eb3768db) Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman