From: Arnd Bergmann arnd@arndb.de
The check_reserve_boundaries() function has a large array on the stack, over 500 bytes. It gets inlined into __igt_reserve, which has multiple other large structures as well but stayed just under the stack size warning limit of 1024 bytes until one more member got added to struct drm_mm_node, causing a warning:
drivers/gpu/drm/selftests/test-drm_mm.c:371:12: error: stack frame size of 1032 bytes in function '__igt_reserve' [-Werror,-Wframe-larger-than=]
As far as I can tell, this is not nice but will not be called from a context that is already low for the kernel stack, so just annotate the inner function as noinline_for_stack to ensure that each function by itself stays under the warning limit.
Fixes: 0cdea4455acd ("drm/mm: optimize rb_hole_addr rbtree search") Reviewed-by: Chris Wilson chris@chris-wilson.co.uk Link: https://lore.kernel.org/all/20200529201534.474853-1-arnd@arndb.de/ Signed-off-by: Arnd Bergmann arnd@arndb.de --- This happens rather rarely, I just ran into it again and found my old patch. --- drivers/gpu/drm/selftests/test-drm_mm.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/selftests/test-drm_mm.c b/drivers/gpu/drm/selftests/test-drm_mm.c index b768b53c4aee..76973c72855e 100644 --- a/drivers/gpu/drm/selftests/test-drm_mm.c +++ b/drivers/gpu/drm/selftests/test-drm_mm.c @@ -324,9 +324,8 @@ static bool expect_reserve_fail(struct drm_mm *mm, struct drm_mm_node *node) return false; }
-static bool check_reserve_boundaries(struct drm_mm *mm, - unsigned int count, - u64 size) +static noinline_for_stack bool +check_reserve_boundaries(struct drm_mm *mm, unsigned int count, u64 size) { const struct boundary { u64 start, size;