Hi,
On 08/08/2024 07:38, Lin.Cao wrote:
If buddy manager have more than one roots and each root have sub-block
need to be free. When drm_buddy_fini called, the first loop of
force_merge will merge and free all of the sub block of first root,
which offset is 0x0 and size is biggest(more than have of the mm size).
In subsequent force_merge rounds, if we use 0 as start and use remaining
mm size as end, the block of other roots will be skipped in
__force_merge function. It will cause the other roots can not be freed.
Solution: use roots' offset as the start could fix this issue.
Signed-off-by: Lin.Cao <lincao12@xxxxxxx>
Nice catch.
---
drivers/gpu/drm/drm_buddy.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/drm_buddy.c b/drivers/gpu/drm/drm_buddy.c
index 94f8c34fc293..5379687552bc 100644
--- a/drivers/gpu/drm/drm_buddy.c
+++ b/drivers/gpu/drm/drm_buddy.c
@@ -327,12 +327,14 @@ void drm_buddy_fini(struct drm_buddy *mm)
u64 root_size, size;
unsigned int order;
int i;
+ u64 start = 0;
Nit: We could maybe move this into root_size, size or even into the loop
body below? Also no need to init.
size = mm->size;
for (i = 0; i < mm->n_roots; ++i) {
order = ilog2(size) - ilog2(mm->chunk_size);
- __force_merge(mm, 0, size, order);
+ start = drm_buddy_block_offset(mm->roots[i]);
+ __force_merge(mm, start, start + size, order);
WARN_ON(!drm_buddy_block_is_free(mm->roots[i]));
We do seem to have a testcase for this at the bottom of
drm_test_buddy_alloc_clear(), so either it is not triggering the
WARN_ON() here in which case we should maybe improve that. Or it is, but
kunit doesn't treat that as a test failure? Maybe we can call something
like kunit_fail_current_test() here if that WARN_ON is triggered?
For reference our CI is just running all drm selftests with:
/kernel/tools/testing/kunit/kunit.py run --kunitconfig
/kernel/drivers/gpu/drm/tests/.kunitconfig
drm_block_free(mm, mm->roots[i]);
