[PATCH v2 1/1] alloc_tag: mark pages reserved during CMA activation as not tagged

[Suren Baghdasaryan <surenb@google.com>]

During CMA activation, pages in CMA area are prepared and then freed
without being allocated. This triggers warnings when memory allocation
debug config (CONFIG_MEM_ALLOC_PROFILING_DEBUG) is enabled. Fix this
by marking these pages not tagged before freeing them.

Fixes: d224eb0287fb ("codetag: debug: mark codetags for reserved pages as empty")
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Cc: stable@vger.kernel.org # v6.10
---
changes since v1 [1]
- Added Fixes tag
- CC'ed stable

[1] https://lore.kernel.org/all/20240812184455.86580-1-surenb@google.com/

 mm/mm_init.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/mm/mm_init.c b/mm/mm_init.c
index 75c3bd42799b..ec9324653ad9 100644
--- a/mm/mm_init.c
+++ b/mm/mm_init.c
@@ -2245,6 +2245,16 @@ void __init init_cma_reserved_pageblock(struct page *page)
 
 	set_pageblock_migratetype(page, MIGRATE_CMA);
 	set_page_refcounted(page);
+
+	/* pages were reserved and not allocated */
+	if (mem_alloc_profiling_enabled()) {
+		union codetag_ref *ref = get_page_tag_ref(page);
+
+		if (ref) {
+			set_codetag_empty(ref);
+			put_page_tag_ref(ref);
+		}
+	}
 	__free_pages(page, pageblock_order);
 
 	adjust_managed_page_count(page, pageblock_nr_pages);

base-commit: d74da846046aeec9333e802f5918bd3261fb5509
-- 
2.46.0.76.ge559c4bf1a-goog