From 79b2d9fb0d300f21a26437219b5b5d4cc611b25a Mon Sep 17 00:00:00 2001
From: Arunpravin Paneer Selvam <Arunpravin.PaneerSelvam@amd.com>
Date: Mon, 11 Apr 2022 13:08:34 +0530
Subject: drm: add a check to verify the size alignment
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Git-commit: 5f77876013d08fe9d43bb4b7f9f7a81e4d3b63a9
Patch-mainline: v5.19-rc1
References: jsc#PED-1166 jsc#PED-1168 jsc#PED-1170 jsc#PED-1218 jsc#PED-1220 jsc#PED-1222 jsc#PED-1223 jsc#PED-1225
Add a simple check to reject any size not aligned to the
min_page_size.
when size is not aligned to min_page_size, driver module
should handle in their own way either to round_up() the
size value to min_page_size or just to enable WARN_ON().
If we dont handle the alignment properly, we may hit the
following bug, Unigine Heaven has allocation requests for
example required pages are 257 and alignment request is 256.
To allocate the left over 1 page, continues the iteration to
find the order value which is 0 and when it compares with
min_order = 8, triggers the BUG_ON(order < min_order).
v2: add more commit description
v3: remove WARN_ON()
Signed-off-by: Arunpravin Paneer Selvam <Arunpravin.PaneerSelvam@amd.com>
Suggested-by: Matthew Auld <matthew.auld@intel.com>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220411073834.15210-1-Arunpravin.PaneerSelvam@amd.com
Signed-off-by: Christian König <christian.koenig@amd.com>
Acked-by: Patrik Jakobsson <pjakobsson@suse.de>
---
drivers/gpu/drm/drm_buddy.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/gpu/drm/drm_buddy.c b/drivers/gpu/drm/drm_buddy.c
index 72f52f293249..11bb59399471 100644
--- a/drivers/gpu/drm/drm_buddy.c
+++ b/drivers/gpu/drm/drm_buddy.c
@@ -665,6 +665,9 @@ int drm_buddy_alloc_blocks(struct drm_buddy *mm,
if (start + size == end)
return __drm_buddy_alloc_range(mm, start, size, blocks);
+ if (!IS_ALIGNED(size, min_page_size))
+ return -EINVAL;
+
pages = size >> ilog2(mm->chunk_size);
order = fls(pages) - 1;
min_order = ilog2(min_page_size) - ilog2(mm->chunk_size);
--
2.38.1