linux-kernel - [PATCH 02/41] maple_tree: Detect dead nodes in mas

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]

Date:   Mon,  9 Jan 2023 12:52:57 -0800
From:   Suren Baghdasaryan <surenb@...gle.com>
To:     akpm@...ux-foundation.org
Cc:     michel@...pinasse.org, jglisse@...gle.com, mhocko@...e.com,
        vbabka@...e.cz, hannes@...xchg.org, mgorman@...hsingularity.net,
        dave@...olabs.net, willy@...radead.org, liam.howlett@...cle.com,
        peterz@...radead.org, ldufour@...ux.ibm.com,
        laurent.dufour@...ibm.com, paulmck@...nel.org, luto@...nel.org,
        songliubraving@...com, peterx@...hat.com, david@...hat.com,
        dhowells@...hat.com, hughd@...gle.com, bigeasy@...utronix.de,
        kent.overstreet@...ux.dev, punit.agrawal@...edance.com,
        lstoakes@...il.com, peterjung1337@...il.com, rientjes@...gle.com,
        axelrasmussen@...gle.com, joelaf@...gle.com, minchan@...gle.com,
        jannh@...gle.com, shakeelb@...gle.com, tatashin@...gle.com,
        edumazet@...gle.com, gthelen@...gle.com, gurua@...gle.com,
        arjunroy@...gle.com, soheil@...gle.com, hughlynch@...gle.com,
        leewalsh@...gle.com, posk@...gle.com, linux-mm@...ck.org,
        linux-arm-kernel@...ts.infradead.org,
        linuxppc-dev@...ts.ozlabs.org, x86@...nel.org,
        linux-kernel@...r.kernel.org, kernel-team@...roid.com,
        surenb@...gle.com, Liam Howlett <Liam.Howlett@...cle.com>
Subject: [PATCH 02/41] maple_tree: Detect dead nodes in mas_start()

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

When initially starting a search, the root node may already be in the
process of being replaced in RCU mode.  Detect and restart the walk if
this is the case.  This is necessary for RCU mode of the maple tree.

Fixes: 54a611b60590 ("Maple Tree: add new data structure")
Signed-off-by: Liam Howlett <Liam.Howlett@...cle.com>
Signed-off-by: Suren Baghdasaryan <surenb@...gle.com>
---
 lib/maple_tree.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/lib/maple_tree.c b/lib/maple_tree.c
index ff9f04e0150d..a748938ad2e9 100644
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -1359,11 +1359,15 @@ static inline struct maple_enode *mas_start(struct ma_state *mas)
 		mas->depth = 0;
 		mas->offset = 0;
 
+retry:
 		root = mas_root(mas);
 		/* Tree with nodes */
 		if (likely(xa_is_node(root))) {
 			mas->depth = 1;
 			mas->node = mte_safe_root(root);
+			if (mte_dead_node(mas->node))
+				goto retry;
+
 			return NULL;
 		}
 
-- 
2.39.0