Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 748AEC61DA7 for ; Fri, 27 Jan 2023 19:58:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233241AbjA0T6J (ORCPT ); Fri, 27 Jan 2023 14:58:09 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37590 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233105AbjA0T5i (ORCPT ); Fri, 27 Jan 2023 14:57:38 -0500 Received: from mail-yw1-x1149.google.com (mail-yw1-x1149.google.com [IPv6:2607:f8b0:4864:20::1149]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 827C68CE0E for ; Fri, 27 Jan 2023 11:55:37 -0800 (PST) Received: by mail-yw1-x1149.google.com with SMTP id 00721157ae682-4fee82718afso65564437b3.5 for ; Fri, 27 Jan 2023 11:55:37 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=SRJKiHKrq/SvrK23nJ6WvAwYz6ftOZ3c7xtMrR/Zkmo=; b=q++c4JbFs1cULNmXHJ6C3DczcQ0hXzOKIr6+9Qx2yz39vZWA+rjLc18PKWJkWy6B+C UeBdui8K3sk0l0OIGcxNzLRt494xbxI7WVRAtP+VLTOL1/q+UNWJf0WDLHuQPthduco2 hKKj52t3wKu54Vbflyx5DWFngCga+0YCh2aWf3wXfSgRE76VHyLLWka1QvKlb5EEsVq+ yKsc5SnLc4E9cZlzwXYLALtVVR/qLY2NGEjlF8VIz3gJJ8VVrEVxdVCt2bqpvNVXSzLO bCSv1unz+7C8JA4tTmfPKXKgKgaiBEIUDtx7XKU+dM+xg3yKNZdzkdQzW0TW1MecPnG9 7xHA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=SRJKiHKrq/SvrK23nJ6WvAwYz6ftOZ3c7xtMrR/Zkmo=; b=7lYglgmIJOhTygxrBuL2xHFAQv6Cyeu6N45WB8ACorCeqqC+OmB6jswNMJ+VBsA+2t BfR82ptjgHY3mkm9ZVoALZYaK+N6hI0pO+n+6R+00yoec21jB+nwKD3I25ZMjRSNhsF4 E50lXpwQ6Cky4oh300k5CpVFNcbTIhMLxWKG5jXg+22j3FNNPLCcs8HfhsW81Tolf2BC f1Aa3aFDvuUH+7flBPnpHAp4YDyOJAJesEQ0VF08xiCk8LfhtcspvWR16QSW5lFN/WYj R4sZXWztTqFlFZKoapKa7IXdl2ufzAtBJ7o9RS1/d7DrG8Jzu61loAiPzxVIvWhHFRTN aD0A== X-Gm-Message-State: AFqh2koej8TwI34zFPQB3NG0Mm7M5nm4XGoesfk+4YGnPaZzhplMjB+A S+jEfAFGrOgGNMTPGUQz+kpoFTAWxl8= X-Google-Smtp-Source: AMrXdXvEqVwWOYAYjpqjq4VZxkQLftXilDeGRL6KyIgBgBs2rP6fdUqH1kwtp8PmmItyT8YCkU5DjbIMLFI= X-Received: from surenb-desktop.mtv.corp.google.com ([2620:15c:211:200:4e19:be9:c5d0:8483]) (user=surenb job=sendgmr) by 2002:a25:4e54:0:b0:7fe:6d35:1a28 with SMTP id c81-20020a254e54000000b007fe6d351a28mr4351236ybb.534.1674848476456; Fri, 27 Jan 2023 11:41:16 -0800 (PST) Date: Fri, 27 Jan 2023 11:40:38 -0800 In-Reply-To: <20230127194110.533103-1-surenb@google.com> Mime-Version: 1.0 References: <20230127194110.533103-1-surenb@google.com> X-Mailer: git-send-email 2.39.1.456.gfc5497dd1b-goog Message-ID: <20230127194110.533103-2-surenb@google.com> Subject: [PATCH v2 01/33] maple_tree: Be more cautious about dead nodes From: Suren Baghdasaryan To: akpm@linux-foundation.org Cc: michel@lespinasse.org, jglisse@google.com, mhocko@suse.com, vbabka@suse.cz, hannes@cmpxchg.org, mgorman@techsingularity.net, dave@stgolabs.net, willy@infradead.org, liam.howlett@oracle.com, peterz@infradead.org, ldufour@linux.ibm.com, paulmck@kernel.org, mingo@redhat.com, will@kernel.org, luto@kernel.org, songliubraving@fb.com, peterx@redhat.com, david@redhat.com, dhowells@redhat.com, hughd@google.com, bigeasy@linutronix.de, kent.overstreet@linux.dev, punit.agrawal@bytedance.com, lstoakes@gmail.com, peterjung1337@gmail.com, rientjes@google.com, axelrasmussen@google.com, joelaf@google.com, minchan@google.com, rppt@kernel.org, jannh@google.com, shakeelb@google.com, tatashin@google.com, edumazet@google.com, gthelen@google.com, gurua@google.com, arjunroy@google.com, soheil@google.com, leewalsh@google.com, posk@google.com, linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, x86@kernel.org, linux-kernel@vger.kernel.org, kernel-team@android.com, surenb@google.com, Liam Howlett Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Liam Howlett ma_pivots() and ma_data_end() may be called with a dead node. Ensure to that the node isn't dead before using the returned values. This is necessary for RCU mode of the maple tree. Fixes: 54a611b60590 ("Maple Tree: add new data structure") Signed-off-by: Liam Howlett Signed-off-by: Suren Baghdasaryan --- lib/maple_tree.c | 52 +++++++++++++++++++++++++++++++++++++++--------- 1 file changed, 43 insertions(+), 9 deletions(-) diff --git a/lib/maple_tree.c b/lib/maple_tree.c index 5e9703189259..e5eeecd14eee 100644 --- a/lib/maple_tree.c +++ b/lib/maple_tree.c @@ -537,6 +537,7 @@ static inline bool ma_dead_node(const struct maple_node *node) return (parent == node); } + /* * mte_dead_node() - check if the @enode is dead. * @enode: The encoded maple node @@ -618,6 +619,8 @@ static inline unsigned int mas_alloc_req(const struct ma_state *mas) * @node - the maple node * @type - the node type * + * In the event of a dead node, this array may be %NULL + * * Return: A pointer to the maple node pivots */ static inline unsigned long *ma_pivots(struct maple_node *node, @@ -1089,8 +1092,11 @@ static int mas_ascend(struct ma_state *mas) a_type = mas_parent_enum(mas, p_enode); a_node = mte_parent(p_enode); a_slot = mte_parent_slot(p_enode); - pivots = ma_pivots(a_node, a_type); a_enode = mt_mk_node(a_node, a_type); + pivots = ma_pivots(a_node, a_type); + + if (unlikely(ma_dead_node(a_node))) + return 1; if (!set_min && a_slot) { set_min = true; @@ -1394,6 +1400,9 @@ static inline unsigned char ma_data_end(struct maple_node *node, { unsigned char offset; + if (!pivots) + return 0; + if (type == maple_arange_64) return ma_meta_end(node, type); @@ -1429,6 +1438,9 @@ static inline unsigned char mas_data_end(struct ma_state *mas) return ma_meta_end(node, type); pivots = ma_pivots(node, type); + if (unlikely(ma_dead_node(node))) + return 0; + offset = mt_pivots[type] - 1; if (likely(!pivots[offset])) return ma_meta_end(node, type); @@ -4498,6 +4510,9 @@ static inline int mas_prev_node(struct ma_state *mas, unsigned long min) node = mas_mn(mas); slots = ma_slots(node, mt); pivots = ma_pivots(node, mt); + if (unlikely(ma_dead_node(node))) + return 1; + mas->max = pivots[offset]; if (offset) mas->min = pivots[offset - 1] + 1; @@ -4519,6 +4534,9 @@ static inline int mas_prev_node(struct ma_state *mas, unsigned long min) slots = ma_slots(node, mt); pivots = ma_pivots(node, mt); offset = ma_data_end(node, mt, pivots, mas->max); + if (unlikely(ma_dead_node(node))) + return 1; + if (offset) mas->min = pivots[offset - 1] + 1; @@ -4567,6 +4585,7 @@ static inline int mas_next_node(struct ma_state *mas, struct maple_node *node, struct maple_enode *enode; int level = 0; unsigned char offset; + unsigned char node_end; enum maple_type mt; void __rcu **slots; @@ -4590,7 +4609,11 @@ static inline int mas_next_node(struct ma_state *mas, struct maple_node *node, node = mas_mn(mas); mt = mte_node_type(mas->node); pivots = ma_pivots(node, mt); - } while (unlikely(offset == ma_data_end(node, mt, pivots, mas->max))); + node_end = ma_data_end(node, mt, pivots, mas->max); + if (unlikely(ma_dead_node(node))) + return 1; + + } while (unlikely(offset == node_end)); slots = ma_slots(node, mt); pivot = mas_safe_pivot(mas, pivots, ++offset, mt); @@ -4606,6 +4629,9 @@ static inline int mas_next_node(struct ma_state *mas, struct maple_node *node, mt = mte_node_type(mas->node); slots = ma_slots(node, mt); pivots = ma_pivots(node, mt); + if (unlikely(ma_dead_node(node))) + return 1; + offset = 0; pivot = pivots[0]; } @@ -4652,11 +4678,14 @@ static inline void *mas_next_nentry(struct ma_state *mas, return NULL; } - pivots = ma_pivots(node, type); slots = ma_slots(node, type); - mas->index = mas_safe_min(mas, pivots, mas->offset); + pivots = ma_pivots(node, type); count = ma_data_end(node, type, pivots, mas->max); - if (ma_dead_node(node)) + if (unlikely(ma_dead_node(node))) + return NULL; + + mas->index = mas_safe_min(mas, pivots, mas->offset); + if (unlikely(ma_dead_node(node))) return NULL; if (mas->index > max) @@ -4810,6 +4839,11 @@ static inline void *mas_prev_nentry(struct ma_state *mas, unsigned long limit, slots = ma_slots(mn, mt); pivots = ma_pivots(mn, mt); + if (unlikely(ma_dead_node(mn))) { + mas_rewalk(mas, index); + goto retry; + } + if (offset == mt_pivots[mt]) pivot = mas->max; else @@ -6624,11 +6658,11 @@ static inline void *mas_first_entry(struct ma_state *mas, struct maple_node *mn, while (likely(!ma_is_leaf(mt))) { MT_BUG_ON(mas->tree, mte_dead_node(mas->node)); slots = ma_slots(mn, mt); - pivots = ma_pivots(mn, mt); - max = pivots[0]; entry = mas_slot(mas, slots, 0); + pivots = ma_pivots(mn, mt); if (unlikely(ma_dead_node(mn))) return NULL; + max = pivots[0]; mas->node = entry; mn = mas_mn(mas); mt = mte_node_type(mas->node); @@ -6648,13 +6682,13 @@ static inline void *mas_first_entry(struct ma_state *mas, struct maple_node *mn, if (likely(entry)) return entry; - pivots = ma_pivots(mn, mt); - mas->index = pivots[0] + 1; mas->offset = 1; entry = mas_slot(mas, slots, 1); + pivots = ma_pivots(mn, mt); if (unlikely(ma_dead_node(mn))) return NULL; + mas->index = pivots[0] + 1; if (mas->index > limit) goto none; -- 2.39.1