On Fri, Feb 09, 2024 at 08:56:24PM +0530, Arunpravin Paneer Selvam wrote:
Few users have observed display corruption when they boot the machine to KDE Plasma or playing games. We have root caused the problem that whenever alloc_range() couldn't find the required memory blocks the function was returning SUCCESS in some of the corner cases.
The right approach would be if the total allocated size is less than the required size, the function should return -ENOSPC.
Cc: stable@vger.kernel.org # 6.7+ Fixes: 0a1844bf0b53 ("drm/buddy: Improve contiguous memory allocation") Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/3097 Tested-by: Mario Limonciello mario.limonciello@amd.com Link: https://patchwork.kernel.org/project/dri-devel/patch/20240207174456.341121-1... Acked-by: Christian König christian.koenig@amd.com Reviewed-by: Matthew Auld matthew.auld@intel.com Signed-off-by: Arunpravin Paneer Selvam Arunpravin.PaneerSelvam@amd.com
New unit test for this would be most excellent - these kind of missed edge cases is exactly what kunit is for. Can you please follow up with, since we don't want to hold up the bugfix for longer? -Sima
drivers/gpu/drm/drm_buddy.c | 6 ++++++ 1 file changed, 6 insertions(+)
diff --git a/drivers/gpu/drm/drm_buddy.c b/drivers/gpu/drm/drm_buddy.c index f57e6d74fb0e..c1a99bf4dffd 100644 --- a/drivers/gpu/drm/drm_buddy.c +++ b/drivers/gpu/drm/drm_buddy.c @@ -539,6 +539,12 @@ static int __alloc_range(struct drm_buddy *mm, } while (1); list_splice_tail(&allocated, blocks);
- if (total_allocated < size) {
err = -ENOSPC;goto err_free;- }
- return 0;
err_undo: -- 2.25.1