linux-kernel - [PATCH 2/2] test_maple_tree: Test exhausted upper limit of mtree_alloc

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20241216190113.1226145-3-Liam.Howlett@oracle.com>
Date: Mon, 16 Dec 2024 14:01:13 -0500
From: "Liam R. Howlett" <Liam.Howlett@...cle.com>
To: Andrew Morton <akpm@...ux-foundation.org>
Cc: maple-tree@...ts.infradead.org, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org, Yang Erkun <yangerkun@...weicloud.com>,
        chuck.lever@...cle.com, brauner@...nel.org,
        "Liam R. Howlett" <Liam.Howlett@...cle.com>
Subject: [PATCH 2/2] test_maple_tree: Test exhausted upper limit of mtree_alloc_cyclic()

From: "Liam R. Howlett" <Liam.Howlett@...cle.com>

When the upper bound of the search is exhausted, the maple state may be
returned in an error state of -EBUSY.  This means maple state needs to
be reset before the second search in mas_alloc_cylic() to ensure the
search happens.  This test ensures the issue is not recreated.

Cc: Yang Erkun <yangerkun@...weicloud.com>
Cc: chuck.lever@...cle.com
Cc: brauner@...nel.org
Signed-off-by: Liam R. Howlett <Liam.Howlett@...cle.com>
---
 lib/test_maple_tree.c | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/lib/test_maple_tree.c b/lib/test_maple_tree.c
index 72bda304b5952..13e2a10d7554d 100644
--- a/lib/test_maple_tree.c
+++ b/lib/test_maple_tree.c
@@ -3738,6 +3738,34 @@ static noinline void __init alloc_cyclic_testing(struct maple_tree *mt)
 	}
 
 	mtree_destroy(mt);
+
+	/*
+	 * Issue with reverse search was discovered
+	 * https://lore.kernel.org/all/20241216060600.287B4C4CED0@smtp.kernel.org/
+	 * Exhausting the allocation area and forcing the search to wrap needs a
+	 * mas_reset() in mas_alloc_cyclic().
+	 */
+	next = 0;
+	mt_init_flags(mt, MT_FLAGS_ALLOC_RANGE);
+	for (int i = 0; i < 1023; i++) {
+		mtree_alloc_cyclic(mt, &location, mt, 2, 1024, &next, GFP_KERNEL);
+		MT_BUG_ON(mt, i != location - 2);
+		MT_BUG_ON(mt, i != next - 3);
+		MT_BUG_ON(mt, mtree_load(mt, location) != mt);
+	}
+	mtree_erase(mt, 123);
+	MT_BUG_ON(mt, mtree_load(mt, 123) != NULL);
+	mtree_alloc_cyclic(mt, &location, mt, 2, 1024, &next, GFP_KERNEL);
+	MT_BUG_ON(mt, 123 != location);
+	MT_BUG_ON(mt, 124 != next);
+	MT_BUG_ON(mt, mtree_load(mt, location) != mt);
+	mtree_erase(mt, 100);
+	mtree_alloc_cyclic(mt, &location, mt, 2, 1024, &next, GFP_KERNEL);
+	MT_BUG_ON(mt, 100 != location);
+	MT_BUG_ON(mt, 101 != next);
+	MT_BUG_ON(mt, mtree_load(mt, location) != mt);
+	mtree_destroy(mt);
+
 	/* Overflow test */
 	next = ULONG_MAX - 1;
 	ret = mtree_alloc_cyclic(mt, &location, mt, 2, ULONG_MAX, &next, GFP_KERNEL);
-- 
2.43.0