struct dc has grown large over time (most of it the two inlined dc_scratch_space copies) and now sits close to the page allocator's 4 MiB contiguous allocation limit. Its actual size is not fixed by the source alone, it also depends on the compiler and the .configk, so it can easily cross 4 MiB, e.g. with a newer GCC or a config change, and once it does dc_create() fails.
dc_create() allocates it with kzalloc(). Once struct dc exceeds 4 MiB the request is rounded up to order 11 (8 MiB), which is above MAX_PAGE_ORDER, so the page allocator warns and returns NULL. dc_create() then fails, DM init fails and amdgpu probe aborts with -EINVAL: WARNING: mm/page_alloc.c:5197 at __alloc_frozen_pages_noprof+0x2f9/0x380 RSI: ...000b RBP: ...000b <- order = 11 (8 MiB) __kmalloc_large_noprof+0x1e/0xc0 dc_create+0x38/0x660 [amdgpu] amdgpu_dm_init+0x2d9/0x510 [amdgpu] dm_hw_init+0x1b/0x90 [amdgpu] amdgpu 0000:03:00.0: hw_init of IP block <dm> failed -22 amdgpu 0000:03:00.0: probe with driver amdgpu failed with error -22 struct dc is software only state, never DMAed and only kept as an opaque pointer, so it needs no physically contiguous memory. Use kvzalloc()/ kvfree() so it falls back to vmalloc(), removing the dependency on MAX_PAGE_ORDER. The underlying bloat of struct dc should be addressed separately. Signed-off-by: Honglei Huang <[email protected]> --- drivers/gpu/drm/amd/display/dc/core/dc.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/amd/display/dc/core/dc.c b/drivers/gpu/drm/amd/display/dc/core/dc.c index b3530fbf32f..65bd927435e 100644 --- a/drivers/gpu/drm/amd/display/dc/core/dc.c +++ b/drivers/gpu/drm/amd/display/dc/core/dc.c @@ -1507,7 +1507,7 @@ static void disable_vbios_mode_if_required( struct dc *dc_create(const struct dc_init_data *init_params) { - struct dc *dc = kzalloc_obj(*dc); + struct dc *dc = kvzalloc_obj(*dc); unsigned int full_pipe_count; if (!dc) @@ -1555,7 +1555,7 @@ struct dc *dc_create(const struct dc_init_data *init_params) destruct_dc: dc_destruct(dc); - kfree(dc); + kvfree(dc); return NULL; } @@ -1604,7 +1604,7 @@ void dc_deinit_callbacks(struct dc *dc) void dc_destroy(struct dc **dc) { dc_destruct(*dc); - kfree(*dc); + kvfree(*dc); *dc = NULL; } -- 2.34.1
