From: Zhaoyang Huang <zhaoyang.huang@xxxxxxxxxx>
Kthread and drivers could fetch memory via alloc_pages directly which make them
hard to debug when leaking. Solve this by introducing __GFP_TRACELEAK and reuse
kmemleak mechanism which unified most of kernel cosuming pages into kmemleak.
Signed-off-by: Zhaoyang Huang <zhaoyang.huang@xxxxxxxxxx>
---
include/linux/gfp.h | 4 +++-
include/linux/page-flags.h | 3 +++
mm/kmemleak.c | 2 +-
mm/page_alloc.c | 6 ++++++
4 files changed, 13 insertions(+), 2 deletions(-)
diff --git a/include/linux/gfp.h b/include/linux/gfp.h
index 2d2ccae..081ab54 100644
--- a/include/linux/gfp.h
+++ b/include/linux/gfp.h
@@ -68,6 +68,7 @@
#else
#define ___GFP_NOLOCKDEP 0
#endif
+#define ___GFP_TRACKLEAK 0x10000000u
/* If the above are modified, __GFP_BITS_SHIFT may need updating */
/*
@@ -259,12 +260,13 @@
#define __GFP_SKIP_ZERO ((__force gfp_t)___GFP_SKIP_ZERO)
#define __GFP_SKIP_KASAN_UNPOISON ((__force gfp_t)___GFP_SKIP_KASAN_UNPOISON)
#define __GFP_SKIP_KASAN_POISON ((__force gfp_t)___GFP_SKIP_KASAN_POISON)
+#define __GFP_TRACKLEAK ((__force gfp_t)___GFP_TRACKLEAK)
/* Disable lockdep for GFP context tracking */
#define __GFP_NOLOCKDEP ((__force gfp_t)___GFP_NOLOCKDEP)
/* Room for N __GFP_FOO bits */
-#define __GFP_BITS_SHIFT (27 + IS_ENABLED(CONFIG_LOCKDEP))
+#define __GFP_BITS_SHIFT (28 + IS_ENABLED(CONFIG_LOCKDEP))
#define __GFP_BITS_MASK ((__force gfp_t)((1 << __GFP_BITS_SHIFT) - 1))
/**
diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index e66f7aa..ef0f814 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -942,6 +942,7 @@ static inline bool is_page_hwpoison(struct page *page)
#define PG_offline 0x00000100
#define PG_table 0x00000200
#define PG_guard 0x00000400
+#define PG_trackleak 0x00000800
#define PageType(page, flag) \
((page->page_type & (PAGE_TYPE_BASE | flag)) == PAGE_TYPE_BASE)
@@ -1012,6 +1013,8 @@ static inline int page_has_type(struct page *page)
*/
PAGE_TYPE_OPS(Guard, guard)
+PAGE_TYPE_OPS(Trackleak, trackleak)
+
extern bool is_free_buddy_page(struct page *page);
PAGEFLAG(Isolated, isolated, PF_ANY);
diff --git a/mm/kmemleak.c b/mm/kmemleak.c
index 422f28f..a182f5d 100644
--- a/mm/kmemleak.c
+++ b/mm/kmemleak.c
@@ -1471,7 +1471,7 @@ static void kmemleak_scan(void)
if (page_zone(page) != zone)
continue;
/* only scan if page is in use */
- if (page_count(page) == 0 || PageReserved(page))
+ if (page_count(page) == 0)
continue;
scan_block(page, page + 1, NULL);
if (!(pfn & 63))
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index e008a3d..d8995c6 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1361,6 +1361,8 @@ static __always_inline bool free_pages_prepare(struct page *page,
page->mapping = NULL;
if (memcg_kmem_enabled() && PageMemcgKmem(page))
__memcg_kmem_uncharge_page(page, order);
+ if (PageTrackleak(page))
+ kmemleak_free(page);
if (check_free)
bad += check_free_page(page);
if (bad)
@@ -5444,6 +5446,10 @@ struct page *__alloc_pages(gfp_t gfp, unsigned int order, int preferred_nid,
__free_pages(page, order);
page = NULL;
}
+ if (gfp & __GFP_TRACKLEAK) {
+ kmemleak_alloc(page_address(page), PAGE_SIZE << order, 1, gfp & ~__GFP_TRACKLEAK);
+ __SetPageTrackleak(page);
+ }
trace_mm_page_alloc(page, order, alloc_gfp, ac.migratetype);
--
1.9.1
