From 183182235f6d53bac62c6c39014738a54a68dfa6 Mon Sep 17 00:00:00 2001 From: Mikhail Gavrilov Date: Tue, 5 May 2026 09:05:37 +0800 Subject: [PATCH] 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: 235c67634230 ("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 Signed-off-by: Mikhail Gavrilov Signed-off-by: James Lin Tested-by: Daniel Wheeler Signed-off-by: Alex Deucher (cherry picked from commit 885ccbef7b94a8b38f69c4211c679021aa27ad11) Cc: stable@vger.kernel.org --- .../drm/amd/display/dc/resource/dcn32/dcn32_resource.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) 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 82f81b586986..3751f7a94a05 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 @@ -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;