linux-kernel - [PATCH v3 2/2] alloc_tag: mark pages reserved during CMA activation as not tagged

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Message-ID: <20240813150758.855881-2-surenb@google.com>
Date: Tue, 13 Aug 2024 08:07:57 -0700
From: Suren Baghdasaryan <surenb@...gle.com>
To: akpm@...ux-foundation.org
Cc: kent.overstreet@...ux.dev, david@...hat.com, vbabka@...e.cz, 
	pasha.tatashin@...een.com, souravpanda@...gle.com, keescook@...omium.org, 
	linux-kernel@...r.kernel.org, linux-mm@...ck.org, surenb@...gle.com, 
	stable@...r.kernel.org
Subject: [PATCH v3 2/2] alloc_tag: mark pages reserved during CMA activation
 as not tagged

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@...gle.com>
Cc: stable@...r.kernel.org # v6.10
---
Changes since v2 [1]:
- Add and use clear_page_tag_ref helper, per David Hildenbrand

https://lore.kernel.org/all/20240812192428.151825-1-surenb@google.com/

 mm/mm_init.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/mm/mm_init.c b/mm/mm_init.c
index 907c46b0773f..13c4060bb01a 100644
--- a/mm/mm_init.c
+++ b/mm/mm_init.c
@@ -2245,6 +2245,8 @@ 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 */
+	clear_page_tag_ref(page);
 	__free_pages(page, pageblock_order);
 
 	adjust_managed_page_count(page, pageblock_nr_pages);
-- 
2.46.0.76.ge559c4bf1a-goog