linux-kernel - [PATCH 2/2] mm/kmemleak: No need to check kmemleak_initialized in set_track

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Date:   Thu, 10 Aug 2023 15:47:04 +0800
From:   Xiaolei Wang <xiaolei.wang@...driver.com>
To:     catalin.marinas@....com, akpm@...ux-foundation.org,
        glider@...gle.com, andreyknvl@...il.com, vbabka@...e.cz,
        zhaoyang.huang@...soc.com
Cc:     linux-mm@...ck.org, linux-kernel@...r.kernel.org
Subject: [PATCH 2/2] mm/kmemleak: No need to check kmemleak_initialized in set_track_prepare()

The kmemleak_late_init() is defined as a late_initcall. The current
implementation of set_track_prepare() depends on the kmemleak init.
That also means there is no call trace for the memory leak which object
is created before the kmemleak_late_init().



In a previous patch, we have fixed a bug in stack_depot_save() so that
it can be invoked even before stack depot is initialized. So there is
no reason to check the kmemleak_initialized in set_track_prepare().
So delete the kmemleak_initialized judgment in set_track_prepare()

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 | 2 --
 1 file changed, 2 deletions(-)

diff --git a/mm/kmemleak.c b/mm/kmemleak.c
index a2d34226e3c8..c9f2f816db19 100644
--- a/mm/kmemleak.c
+++ b/mm/kmemleak.c
@@ -610,8 +610,6 @@ static noinline depot_stack_handle_t set_track_prepare(void)
 	unsigned long entries[MAX_TRACE];
 	unsigned int nr_entries;
 
-	if (!kmemleak_initialized)
-		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