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Date: Mon, 12 Feb 2024 13:39:19 -0800
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Subject: [PATCH v3 33/35] codetag: debug: mark codetags for reserved pages as empty
From: Suren Baghdasaryan <surenb@google.com>
To: akpm@linux-foundation.org
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Content-Type: text/plain; charset="UTF-8"

To avoid debug warnings while freeing reserved pages which were not
allocated with usual allocators, mark their codetags as empty before
freeing.

Signed-off-by: Suren Baghdasaryan <surenb@google.com>
---
 include/linux/alloc_tag.h   | 2 ++
 include/linux/mm.h          | 8 ++++++++
 include/linux/pgalloc_tag.h | 2 ++
 mm/mm_init.c                | 9 +++++++++
 4 files changed, 21 insertions(+)

diff --git a/include/linux/alloc_tag.h b/include/linux/alloc_tag.h
index 1f3207097b03..102caf62c2a9 100644
--- a/include/linux/alloc_tag.h
+++ b/include/linux/alloc_tag.h
@@ -95,6 +95,7 @@ static inline void set_codetag_empty(union codetag_ref *ref)
 #else /* CONFIG_MEM_ALLOC_PROFILING_DEBUG */
 
 static inline bool is_codetag_empty(union codetag_ref *ref) { return false; }
+static inline void set_codetag_empty(union codetag_ref *ref) {}
 
 #endif /* CONFIG_MEM_ALLOC_PROFILING_DEBUG */
 
@@ -155,6 +156,7 @@ static inline void alloc_tag_sub(union codetag_ref *ref, size_t bytes) {}
 static inline void alloc_tag_sub_noalloc(union codetag_ref *ref, size_t bytes) {}
 static inline void alloc_tag_add(union codetag_ref *ref, struct alloc_tag *tag,
 				 size_t bytes) {}
+static inline void set_codetag_empty(union codetag_ref *ref) {}
 
 #endif
 
diff --git a/include/linux/mm.h b/include/linux/mm.h
index f5a97dec5169..ac1b661987ed 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -5,6 +5,7 @@
 #include <linux/errno.h>
 #include <linux/mmdebug.h>
 #include <linux/gfp.h>
+#include <linux/pgalloc_tag.h>
 #include <linux/bug.h>
 #include <linux/list.h>
 #include <linux/mmzone.h>
@@ -3112,6 +3113,13 @@ extern void reserve_bootmem_region(phys_addr_t start,
 /* Free the reserved page into the buddy system, so it gets managed. */
 static inline void free_reserved_page(struct page *page)
 {
+	union codetag_ref *ref;
+
+	ref = get_page_tag_ref(page);
+	if (ref) {
+		set_codetag_empty(ref);
+		put_page_tag_ref(ref);
+	}
 	ClearPageReserved(page);
 	init_page_count(page);
 	__free_page(page);
diff --git a/include/linux/pgalloc_tag.h b/include/linux/pgalloc_tag.h
index 0174aff5e871..ae9b0f359264 100644
--- a/include/linux/pgalloc_tag.h
+++ b/include/linux/pgalloc_tag.h
@@ -93,6 +93,8 @@ static inline void pgalloc_tag_split(struct page *page, unsigned int nr)
 
 #else /* CONFIG_MEM_ALLOC_PROFILING */
 
+static inline union codetag_ref *get_page_tag_ref(struct page *page) { return NULL; }
+static inline void put_page_tag_ref(union codetag_ref *ref) {}
 static inline void pgalloc_tag_add(struct page *page, struct task_struct *task,
 				   unsigned int order) {}
 static inline void pgalloc_tag_sub(struct page *page, unsigned int order) {}
diff --git a/mm/mm_init.c b/mm/mm_init.c
index e9ea2919d02d..f5386632fe86 100644
--- a/mm/mm_init.c
+++ b/mm/mm_init.c
@@ -2566,6 +2566,7 @@ void __init set_dma_reserve(unsigned long new_dma_reserve)
 void __init memblock_free_pages(struct page *page, unsigned long pfn,
 							unsigned int order)
 {
+	union codetag_ref *ref;
 
 	if (IS_ENABLED(CONFIG_DEFERRED_STRUCT_PAGE_INIT)) {
 		int nid = early_pfn_to_nid(pfn);
@@ -2578,6 +2579,14 @@ void __init memblock_free_pages(struct page *page, unsigned long pfn,
 		/* KMSAN will take care of these pages. */
 		return;
 	}
+
+	/* pages were reserved and not allocated */
+	ref = get_page_tag_ref(page);
+	if (ref) {
+		set_codetag_empty(ref);
+		put_page_tag_ref(ref);
+	}
+
 	__free_pages_core(page, order);
 }
 
-- 
2.43.0.687.g38aa6559b0-goog