From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from m16.mail.163.com (m16.mail.163.com [220.197.31.3]) (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 0D8634229A6; Wed, 2 Sep 2026 09:38:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=220.197.31.3 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788341920; cv=none; b=bdjOZYqj8rBSUT7OHwzNh9E83GGN4h+pReZao7MVYSSK6kjX0Bbw4WmTdmAM7ZI38KmuIbiEgLkKp77WdkK1gf6yprkWUWIC+iXbQNM0w7+RX3lhPou+PbS5Wnr/6npwXYAdGp2VOqLb+3MTczG7A2tZzdCgdal+Nilp2OgVQMM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788341920; c=relaxed/simple; bh=IwROk44CZaQG+siuubT32QXiRJHbp5/a/TuPA93r2pQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=LtaS34C2odJRT+5uZcU9hVRe9l+UZ9/tIICC0dtuPp8Y5wRXPy9ZnOb4eVjiwNVlAVpr/xVjyGlLLtllGlfnxLBfYChmJ8FNOep+Vf9BI1Evttp/M95oUtydRSSUfIg/x8AvtA8IiqzME7bbx95lIGX3vEfYC17eYAy+KA6e2Bw= 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=PFufibr8; arc=none smtp.client-ip=220.197.31.3 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="PFufibr8" 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=zr VKOIfZyNfdBaup7kUIwUMlr9Bdz0dloClPNSFyXyY=; b=PFufibr8UkN7dLNEP4 e3w84zL+/Fj0jHTso8J/7oZSBacGgvQ93plbH0KoHMsyEwuJrp/p7TlOnmdbhU0M qgeACe4oAcustGRdyRkVzkwY9zkVoGDHKHtkjpG0fvlRyf1A6jlCz7nsjZtTR5xB adOWQC51HXVoYshU7dMxl8Ijs= Received: from nec8-i7 (unknown []) by gzga-smtp-mtada-g0-0 (Coremail) with SMTP id _____wD3F7Vu7pdqogtpAA--.21222S4; Wed, 02 Sep 2026 17:37:54 +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 , Emil Tsalapatis , Ihor Solodrai , Yuan Chen Subject: [PATCH bpf-next v5 2/3] bpf, arena: fix range_tree_set inconsistency on kmalloc_nolock failure Date: Wed, 2 Sep 2026 17:37:39 +0800 Message-ID: <20260902093740.2338724-3-chenyuan_fl@163.com> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260902093740.2338724-1-chenyuan_fl@163.com> References: <20260902093740.2338724-1-chenyuan_fl@163.com> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CM-TRANSID:_____wD3F7Vu7pdqogtpAA--.21222S4 X-Coremail-Antispam: 1Uf129KBjvJXoWxCw13AF1kWr48GF4xAFy8Grg_yoW5CFWrpw 15KrWrJrsxJ3y7Ww1Fvr48uFyrCw1fXw4ktrZxGw4kA3W5Ar97AFn0kF4jkFWDAFy8Cr15 tF1jv3y7GF4UuFDanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x07jbo7NUUUUU= X-CM-SenderInfo: xfkh05pxdqswro6rljoofrz/xtbDAhJYFmqX7nIOyAAA35 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). Signed-off-by: Yuan Chen --- kernel/bpf/range_tree.c | 45 +++++++++++++++++++++++++++++++---------- 1 file changed, 34 insertions(+), 11 deletions(-) diff --git a/kernel/bpf/range_tree.c b/kernel/bpf/range_tree.c index 15b588377a76..0420ab715f20 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 +209,40 @@ int range_tree_set(struct range_tree *rt, u32 start, u32 len) if (left && left->rn_start <= start && left->rn_last >= last) return 0; + /* + * The pre-clear probe only decides whether a fresh node is needed; + * adjacency on either side is invariant across the clear, so it can + * run before the tree is modified and -ENOMEM leaves it untouched. + * The merge below re-fetches its handles after the clear instead of + * relying on the overlapping nodes being updated in place. + */ + 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; + goto out_free_new; /* 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; + if (left && left->rn_last + 1 != start) { + err = -EFAULT; + goto out_free_new; + } /* 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; + if (right && right->rn_start != last + 1) { + err = -EFAULT; + goto out_free_new; + } if (left && right) { /* Combine left and right adjacent ranges */ @@ -241,14 +262,16 @@ 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