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

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Message-ID: <20240812192428.151825-1-surenb@google.com>
Date: Mon, 12 Aug 2024 12:24:28 -0700
From: Suren Baghdasaryan <surenb@...gle.com>
To: akpm@...ux-foundation.org
Cc: kent.overstreet@...ux.dev, 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 v2 1/1] 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 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