From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 78C6F2F24 for ; Wed, 12 Apr 2023 08:53:31 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id F3473C433EF; Wed, 12 Apr 2023 08:53:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1681289611; bh=t9Lrv3v38eyPdkvoLLKHmAz+5EoARDyROTsTMmLg7r0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=dBc7rPNNtRagOl3FO9IDS7U8qurzygehZuWaVH33SfAPRouKsJ/nT61kmuU8ID2+w LrCmyHF9Rd6BcVB2tQPIcdbyNCKXhIvkqx+YDnO6c/1TFOAGD1WmMliApv9p7Iu5dY fQpC868+HzVnIs4Y/YlX9zZlcevsPztl3ypb9qEY= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Stable@vger.kernel.org, Liam Howlett Subject: [PATCH 6.2 166/173] maple_tree: be more cautious about dead nodes Date: Wed, 12 Apr 2023 10:34:52 +0200 Message-Id: <20230412082844.864838280@linuxfoundation.org> X-Mailer: git-send-email 2.40.0 In-Reply-To: <20230412082838.125271466@linuxfoundation.org> References: <20230412082838.125271466@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: "Liam R. Howlett" commit 39d0bd86c499ecd6abae42a9b7112056c5560691 upstream. 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. Link: https://lkml.kernel.org/r/20230227173632.3292573-1-surenb@google.com Link: https://lkml.kernel.org/r/20230227173632.3292573-2-surenb@google.com Fixes: 54a611b60590 ("Maple Tree: add new data structure") Cc: Signed-off-by: Liam Howlett Signed-off-by: Greg Kroah-Hartman --- lib/maple_tree.c | 52 +++++++++++++++++++++++++++++++++++++++++++--------- 1 file changed, 43 insertions(+), 9 deletions(-) --- a/lib/maple_tree.c +++ b/lib/maple_tree.c @@ -539,6 +539,7 @@ static inline bool ma_dead_node(const st return (parent == node); } + /* * mte_dead_node() - check if the @enode is dead. * @enode: The encoded maple node @@ -620,6 +621,8 @@ static inline unsigned int mas_alloc_req * @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, @@ -1091,8 +1094,11 @@ static int mas_ascend(struct ma_state *m 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; @@ -1398,6 +1404,9 @@ static inline unsigned char ma_data_end( { unsigned char offset; + if (!pivots) + return 0; + if (type == maple_arange_64) return ma_meta_end(node, type); @@ -1433,6 +1442,9 @@ static inline unsigned char mas_data_end 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 m 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 m 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 m 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 m 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 m 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(stru 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) @@ -4814,6 +4843,11 @@ retry: 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 @@ -6616,11 +6650,11 @@ static inline void *mas_first_entry(stru 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); @@ -6640,13 +6674,13 @@ static inline void *mas_first_entry(stru 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;