From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 37C683F4DFC; Wed, 20 May 2026 17:03:29 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779296610; cv=none; b=ijZ3qUkW72M65MX4rQiZufANV2/IdNXi73hZ8i7LZkKWUvsXhMrElbOQZk0fZM70GwbvdKe1DlgC9MV1SKqPg43RsLmuX2S8EKspx3BGFvi0hxrXcJJJhI52rsqvIvIpXqzAXy4EtKaAyOSUostBftKRm2/m138i26UjEKDtNpU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779296610; c=relaxed/simple; bh=V4tjfvU118CGXC7Nyk/4Lc23N/g2Z+nLKgO099FwFKQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=pzlPhykqDsoRObSsG5ZHpIXILnc1MUH/uGTGFmPBqeN82fEtnvSLvZuaIAJs0eO8alGKWff1fmATjKMJ8zZeDOR/ayYOc/7KRcBYJGHG43M11KqPWSyrkdcI5g6gbJMDW/8gUCHl0zg1QEZD8O3faTGKXfxlkzZPDUAAFcDbsxw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=BF2VFELt; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="BF2VFELt" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9CD1F1F000E9; Wed, 20 May 2026 17:03:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1779296609; bh=t/nIWMapKtH6dS25UqF9kYfZEE+5GOv9pDoYsx8R0Os=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=BF2VFELtaH80ymuRe2r3K0NAzcYlZoIrczls06BM8MdFNE2uZhxhQKiZQYnUwbBN7 9zgD0c1EvZIT9wVIgFgVDuFKn5DvQz7LQ5eCSsEFkYju4Urt6KmKxQVzIyh/VOCpj5 lbC6NY1IlSgvSm6EZvKMVov150vchBaVafmv0YHY= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, "Christian Brauner (Amutable)" , Sasha Levin Subject: [PATCH 7.0 0862/1146] eventpoll: use hlist_is_singular_node() in __ep_remove() Date: Wed, 20 May 2026 18:18:32 +0200 Message-ID: <20260520162207.747363156@linuxfoundation.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260520162148.390695140@linuxfoundation.org> References: <20260520162148.390695140@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 7.0-stable review patch. If anyone has any objections, please let me know. ------------------ From: Christian Brauner [ Upstream commit 3d9fd0abc94d8cd430cc7cd7d37ce5e5aae2cd2b ] Replace the open-coded "epi is the only entry in file->f_ep" check with hlist_is_singular_node(). Same semantics, and the helper avoids the head-cacheline access in the common false case. Link: https://patch.msgid.link/20260423-work-epoll-uaf-v1-1-2470f9eec0f5@kernel.org Signed-off-by: Christian Brauner (Amutable) Stable-dep-of: a6dc643c6931 ("eventpoll: fix ep_remove struct eventpoll / struct file UAF") Signed-off-by: Sasha Levin --- fs/eventpoll.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/eventpoll.c b/fs/eventpoll.c index 4b43bf41296d4..3f960473840a6 100644 --- a/fs/eventpoll.c +++ b/fs/eventpoll.c @@ -856,7 +856,7 @@ static bool __ep_remove(struct eventpoll *ep, struct epitem *epi, bool force) to_free = NULL; head = file->f_ep; - if (head->first == &epi->fllink && !epi->fllink.next) { + if (hlist_is_singular_node(&epi->fllink, head)) { /* See eventpoll_release() for details. */ WRITE_ONCE(file->f_ep, NULL); if (!is_file_epoll(file)) { -- 2.53.0