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From: Josh Law <hlcj1234567@gmail.com>
To: "Liam R . Howlett" <Liam.Howlett@oracle.com>,
	Andrew Morton <akpm@linux-foundation.org>
Cc: Alice Ryhl <aliceryhl@google.com>,
	Andrew Ballance <andrewjballance@gmail.com>,
	Josh Law <objecting@objecting.org>,
	maple-tree@lists.infradead.org, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org
Subject: [PATCH 2/3] lib/maple_tree: fix always-true condition in mas_erase()
Date: Thu, 12 Mar 2026 18:40:54 +0000	[thread overview]
Message-ID: <20260312184054.23481-2-objecting@objecting.org> (raw)
In-Reply-To: <20260312184054.23481-1-objecting@objecting.org>

The condition (!mas_is_active(mas) || !mas_is_start(mas)) is always
true because ma_active and ma_start are distinct enum values -- a
state can never be both simultaneously. This causes mas_erase() to
unconditionally reset the status to ma_start, discarding a valid
active walk position.

Change || to && so the reset only fires when the state is neither
active nor start, matching the equivalent guard in mas_walk().

Signed-off-by: Josh Law <objecting@objecting.org>
---
 lib/maple_tree.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/maple_tree.c b/lib/maple_tree.c
index 87a2ba6468ca..9727dcefbf65 100644
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -5574,7 +5574,7 @@ void *mas_erase(struct ma_state *mas)
 	unsigned long index = mas->index;
 	MA_WR_STATE(wr_mas, mas, NULL);
 
-	if (!mas_is_active(mas) || !mas_is_start(mas))
+	if (!mas_is_active(mas) && !mas_is_start(mas))
 		mas->status = ma_start;
 
 write_retry:
-- 
2.34.1


  reply	other threads:[~2026-03-12 18:40 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-03-12 18:40 [PATCH 1/3] lib/maple_tree: fix potential NULL dereference in mas_pop_node() Josh Law
2026-03-12 18:40 ` Josh Law [this message]
2026-03-12 20:45 ` Andrew Morton
2026-03-12 20:49   ` Josh Law
2026-03-12 20:56     ` Josh Law
2026-03-12 21:14       ` Josh Law
2026-03-12 23:00     ` Alice Ryhl
2026-03-12 23:22   ` Pedro Falcato
2026-03-13  7:17     ` Josh Law
2026-03-13  9:05       ` Pedro Falcato
2026-03-13 16:11         ` Josh Law

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