From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from m16.mail.163.com (m16.mail.163.com [117.135.210.5]) (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 100BB386562; Wed, 23 Sep 2026 08:59:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=117.135.210.5 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790153949; cv=none; b=YQRwydPAq0CsgE/I5f8qbvanCCA8WxQwEBAzL7Ls+9Fi4fMxl/KM25hc8k/KaEMyyuVk8PzOkJZWWs8/BXZyM5Yqo4Z42BX5sByt8FWDfpk0b05NvLhQXw1V2n57jkzt+sDwTNNkPrghM3LQ6lw4lKrBSIrGjrrwZuB0MjDiUAs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790153949; c=relaxed/simple; bh=w8wkT5fXa23pw/3oHwR9ps67/78Q3/9hTI6jklhid1A=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=GpcyJazUSMLph+V75n1IH6p6ZIOpAy2TWBhjWvpzMTEk6BbVxb9sfvOkPEo+G17y8KxZZtKki+8eTZuZHV9LyccEfLBosAUbKG0Fcv0m0qIQUEv9cu/myIFxtqZYnnribTdjMldF8oCBjxEs7fJQv/NffN+buYO9elwgQgWOsn0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=163.com; spf=pass smtp.mailfrom=163.com; dkim=pass (1024-bit key) header.d=163.com header.i=@163.com header.b=Th5VcLw+; arc=none smtp.client-ip=117.135.210.5 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=163.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=163.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=163.com header.i=@163.com header.b="Th5VcLw+" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=163.com; s=s110527; h=From:To:Subject:Date:Message-ID:MIME-Version; bh=OM eo3JmIOAHUDm9tz0WFATfA43d2b8nFcgMSqu4KQ4I=; b=Th5VcLw+ERb7poHl59 PogjTh7q89JKsRK3p4slqpX+QZ5eWPiGPJaPyqNDdbgRJHYMcANE6MwZdLVWFwT1 4qlyFQZduIj+D8vdsNbQlObcH01sfQyAfBUfBxRlMEGDzRpVOGYsdCH+Msl0hjI/ thvlI2dUtuzzSuN2iOvUtjpqA= Received: from nec8-i7 (unknown []) by gzga-smtp-mtada-g0-1 (Coremail) with SMTP id _____wD3H8OylLNqSEwzAQ--.5285S4; Wed, 23 Sep 2026 16:58:30 +0800 (CST) From: chenyuan_fl@163.com To: bpf@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Alexei Starovoitov , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Eduard Zingerman , Kumar Kartikeya Dwivedi , Martin KaFai Lau , Song Liu , Yonghong Song , Jiri Olsa , Ihor Solodrai , Yuan Chen Subject: [PATCH bpf-next v7 2/2] bpf, arena: fix range_tree_set inconsistency on kmalloc_nolock failure Date: Wed, 23 Sep 2026 16:58:17 +0800 Message-ID: <20260923085817.365930-3-chenyuan_fl@163.com> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260923085817.365930-1-chenyuan_fl@163.com> References: <20260923085817.365930-1-chenyuan_fl@163.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CM-TRANSID:_____wD3H8OylLNqSEwzAQ--.5285S4 X-Coremail-Antispam: 1Uf129KBjvJXoWxCw13CrWfXFW5Jw1xZw1rXrb_yoW5AF4Upw 45KrWrJrsxJ3y7WwnYvr48CryrCw1fXw48tr9xGw4kAFnxCrn7Ar1YkF4jkF98AFy8ur15 tF4jva1xKa1UuFDanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x07jj9a9UUUUU= X-CM-SenderInfo: xfkh05pxdqswro6rljoofrz/xtbDAhbZl2qzlLYVWwAA3v From: Yuan Chen range_tree_set() pre-allocates the node needed for a brand-new range before calling range_tree_clear(), so an allocation failure returns -ENOMEM without having modified the tree (previously the overlapping nodes were already removed by range_tree_clear() before the allocation was attempted, permanently losing the cleared sub-ranges). The adjacency lookups done before the clear already return the nodes that the merge below needs: range_tree_clear() frees only the nodes that lie entirely inside [start, last], trims the overlapping ones in place, and the split case cannot happen because of the 'already set' check above. Do the lookup once and drop the unreachable -EFAULT checks. Signed-off-by: Yuan Chen --- kernel/bpf/range_tree.c | 36 +++++++++++++++++++----------------- 1 file changed, 19 insertions(+), 17 deletions(-) diff --git a/kernel/bpf/range_tree.c b/kernel/bpf/range_tree.c index 15b588377a76..2460e78d6a55 100644 --- a/kernel/bpf/range_tree.c +++ b/kernel/bpf/range_tree.c @@ -199,6 +199,7 @@ int is_range_tree_set(struct range_tree *rt, u32 start, u32 len) int range_tree_set(struct range_tree *rt, u32 start, u32 len) { u32 last = start + len - 1; + struct range_node *new_rn = NULL; struct range_node *right; struct range_node *left; int err; @@ -208,20 +209,19 @@ int range_tree_set(struct range_tree *rt, u32 start, u32 len) if (left && left->rn_start <= start && left->rn_last >= last) return 0; + left = range_it_iter_first(rt, start - 1, start - 1); + right = range_it_iter_first(rt, last + 1, last + 1); + if (!left && !right) { + new_rn = kmalloc_nolock(sizeof(struct range_node), + __GFP_ACCOUNT, NUMA_NO_NODE); + if (!new_rn) + return -ENOMEM; + } + /* Clear out everything in the range we want to set. */ err = range_tree_clear(rt, start, len); if (err) - return err; - - /* Do we have a left-adjacent range ? */ - left = range_it_iter_first(rt, start - 1, start - 1); - if (left && left->rn_last + 1 != start) - return -EFAULT; - - /* Do we have a right-adjacent range ? */ - right = range_it_iter_first(rt, last + 1, last + 1); - if (right && right->rn_start != last + 1) - return -EFAULT; + goto out_free_new; if (left && right) { /* Combine left and right adjacent ranges */ @@ -241,14 +241,16 @@ int range_tree_set(struct range_tree *rt, u32 start, u32 len) right->rn_start = start; range_it_insert(right, rt); } else { - left = kmalloc_nolock(sizeof(struct range_node), __GFP_ACCOUNT, NUMA_NO_NODE); - if (!left) - return -ENOMEM; - left->rn_start = start; - left->rn_last = last; - range_it_insert(left, rt); + /* No adjacent ranges; use the pre-allocated node */ + new_rn->rn_start = start; + new_rn->rn_last = last; + range_it_insert(new_rn, rt); } return 0; + +out_free_new: + kfree_nolock(new_rn); + return err; } void range_tree_destroy(struct range_tree *rt) -- 2.54.0