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drm/amd/display: Wrap DCN32 phantom-plane allocation in DC_RUN_WITH_PREEMPTION_ENABLED

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[Why]
dcn32_validate_bandwidth() wraps dcn32_internal_validate_bw() with
DC_FP_START()/DC_FP_END(). In x86 non-RT, DC_FP_START takes fpregs_lock(),
which disables local softirqs.

The DML1 path through dcn32_enable_phantom_plane() calls kvzalloc() to
allocate ~335 KiB for dc_plane_state. This triggers the vmalloc path,
which calls BUG_ON(in_interrupt()) because it's invoked within the
FPU-enabled (softirq disabled) region, leading to a kernel crash.

[How]
Wrap the dc_state_create_phantom_plane() call with the
DC_RUN_WITH_PREEMPTION_ENABLED() macro to allow preemption during
this memory allocation.

Fixes: 235c676342 ("drm/amd/display: add DCN32/321 specific files for Display Core")
Closes: https://gitlab.freedesktop.org/drm/amd/-/work_items/4470
Reviewed-by: Aurabindo Pillai <aurabindo.pillai@amd.com>
Signed-off-by: Mikhail Gavrilov <mikhail.v.gavrilov@gmail.com>
Signed-off-by: James Lin <pinglei.lin@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit 885ccbef7b94a8b38f69c4211c679021aa27ad11)
Cc: stable@vger.kernel.org
This commit is contained in:
Mikhail Gavrilov 2026-05-05 09:05:37 +08:00 committed by Alex Deucher
parent 0071e01c61
commit 183182235f
1 changed files with 7 additions and 1 deletions
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8
drivers/gpu/drm/amd/display/dc/resource/dcn32/dcn32_resource.c
View File

@ -92,9 +92,14 @@
#include "dml/dcn32/dcn32_fpu.h"
#include "dc_state_priv.h"
#include "dc_fpu.h"
#include "dml2_0/dml2_wrapper.h"
#if !defined(DC_RUN_WITH_PREEMPTION_ENABLED)
#define DC_RUN_WITH_PREEMPTION_ENABLED(code) code
#endif
#define DC_LOGGER_INIT(logger)
enum dcn32_clk_src_array_id {
@ -1684,7 +1689,8 @@ static void dcn32_enable_phantom_plane(struct dc *dc,
if (curr_pipe->top_pipe && curr_pipe->top_pipe->plane_state == curr_pipe->plane_state)
phantom_plane = prev_phantom_plane;
else
phantom_plane = dc_state_create_phantom_plane(dc, context, curr_pipe->plane_state);
DC_RUN_WITH_PREEMPTION_ENABLED(phantom_plane =
dc_state_create_phantom_plane(dc, context, curr_pipe->plane_state));
if (!phantom_plane)
continue;