linux-kernel - [PATCH v2 1/2] mm/kmemleak: use object_cache instead of kmemleak_initialized to check in set_track

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Date:   Tue, 15 Aug 2023 13:13:57 +0800
From:   Xiaolei Wang <xiaolei.wang@...driver.com>
To:     catalin.marinas@....com, akpm@...ux-foundation.org, vbabka@...e.cz,
        glider@...gle.com, andreyknvl@...il.com, zhaoyang.huang@...soc.com
Cc:     linux-mm@...ck.org, linux-kernel@...r.kernel.org
Subject: [PATCH v2 1/2] mm/kmemleak: use object_cache instead of kmemleak_initialized to check in set_track_prepare()

kmemleak_initialized is set in kmemleak_late_init(), which
also means that there is no call trace which object's memory
leak is before kmemleak_late_init(), so use object_cache instead
of kmemleak_initialized to check in set_track_prepare() to avoid
no call trace records when there is a memory leak in the code
between kmemleak_init() and kmemleak_late_init().

unreferenced object 0xc674ca80 (size 64):
 comm "swapper/0", pid 1, jiffies 4294938337 (age 204.880s)
 hex dump (first 32 bytes):
  80 55 75 c6 80 54 75 c6 00 55 75 c6 80 52 75 c6 .Uu..Tu..Uu..Ru.
  00 53 75 c6 00 00 00 00 00 00 00 00 00 00 00 00 .Su..........

Fixes: 56a61617dd22 ("mm: use stack_depot for recording kmemleak's backtrace")
Signed-off-by: Xiaolei Wang <xiaolei.wang@...driver.com>
---
 mm/kmemleak.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/mm/kmemleak.c b/mm/kmemleak.c
index a2d34226e3c8..04bb4cdbb402 100644
--- a/mm/kmemleak.c
+++ b/mm/kmemleak.c
@@ -610,7 +610,8 @@ static noinline depot_stack_handle_t set_track_prepare(void)
 	unsigned long entries[MAX_TRACE];
 	unsigned int nr_entries;
 
-	if (!kmemleak_initialized)
+	/*Use object_cache to determine whether kmemleak_init() is complete*/
+	if (!object_cache)
 		return 0;
 	nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 3);
 	trace_handle = stack_depot_save(entries, nr_entries, GFP_NOWAIT);
-- 
2.25.1