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From:   Xiaolei Wang <xiaolei.wang@windriver.com>
To:     catalin.marinas@arm.com, akpm@linux-foundation.org,
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Cc:     linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: [PATCH 1/2] lib/stackdepot: Bail out in __stack_depot_save() if the stack_table is not allocated
Date:   Thu, 10 Aug 2023 15:47:03 +0800
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The __stack_depot_save() may be used by some subsystems even before
the stack depot is initialized. So add a check of stack_table in
__stack_depot_save() to make sure no oops in this case.

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

diff --git a/lib/stackdepot.c b/lib/stackdepot.c
index 2f5aa851834e..a0651d013a0d 100644
--- a/lib/stackdepot.c
+++ b/lib/stackdepot.c
@@ -376,7 +376,7 @@ depot_stack_handle_t __stack_depot_save(unsigned long *entries,
 	 */
 	nr_entries = filter_irq_stacks(entries, nr_entries);
 
-	if (unlikely(nr_entries == 0) || stack_depot_disabled)
+	if (unlikely(nr_entries == 0) || stack_depot_disabled || unlikely(!stack_table))
 		goto fast_exit;
 
 	hash = hash_stack(entries, nr_entries);
-- 
2.25.1