Commit 18318223 authored by Mikhail Gavrilov's avatar Mikhail Gavrilov Committed by Alex Deucher
Browse files

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

[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: 235c6763 ("drm/amd/display: add DCN32/321 specific files for Display Core")
Closes: https://gitlab.freedesktop.org/drm/amd/-/work_items/4470


Reviewed-by: default avatarAurabindo Pillai <aurabindo.pillai@amd.com>
Signed-off-by: default avatarMikhail Gavrilov <mikhail.v.gavrilov@gmail.com>
Signed-off-by: default avatarJames Lin <pinglei.lin@amd.com>
Tested-by: default avatarDaniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: default avatarAlex Deucher <alexander.deucher@amd.com>
(cherry picked from commit 885ccbef7b94a8b38f69c4211c679021aa27ad11)
Cc: stable@vger.kernel.org
parent 0071e01c

drivers/gpu/drm/amd/display/dc/resource/dcn32/dcn32_resource.c

+7 −1
Original line number Diff line number Diff line
@@ -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;