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 60F2E343896; Thu, 2 Jul 2026 16:36:20 +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=1783010181; cv=none; b=Y4Vp8Bng8/f3wO3CKtZ9hAUFEwCXvGrCquSm/aC2ADxY19LHbcFF4LBpiPWE6SCvGhg4Od/LUMx86oU9x7T2bC5+7Kv/FoLq6oT/dz93Qn5spHnHEXa96sNrBzWrYfb6U2CW0ZlQk8g5Gn9jDUObVUGOb3J/waLNDr79CethvyU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783010181; c=relaxed/simple; bh=b8JQmBTQNspjDvhf2UgFmLDt9ky4NNa+eZ/K3c1Rk48=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=IwTb4Gy8cqZ8TYsYyr5DVeBywS1osO1qEXbzcsAO7KhcWxokR7pqDXtucNsabJn1hx5XIQ3FUqbiQSPOCfYWWWtnBiaIH3HIpQf1G9svA8zElppQrD73lNisXIlAmJijA8nQ1/ohz6HYihklZHjHKjRMpA9Xk8pE6lmEt7/gciI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=drOklXJd; 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="drOklXJd" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BD8661F000E9; Thu, 2 Jul 2026 16:36:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1783010180; bh=FfyCBBgPo2uQKDI3GD9KZGDXPMMFTyllPGoQTaC8VOs=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=drOklXJdkmdHrjntuCEbDP6VpggyRjDihNC/Skb3V2Iv+LlfO/JM9qvb0kYDlLAmu DzQlx48b2hzDScsFKG411FdbDjRZJsZMsXseJEgDVU4zz/5dTJQxWEEDv/ZUdz3zzP gmIp3VFh7RDXVVCWonj1o8GM1EP6c51Op0FUWS2Y= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, "Christian Brauner (Amutable)" , Quentin Schulz , Sasha Levin Subject: [PATCH 6.12 012/204] eventpoll: use hlist_is_singular_node() in __ep_remove() Date: Thu, 2 Jul 2026 18:17:49 +0200 Message-ID: <20260702155118.927645307@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260702155118.667618796@linuxfoundation.org> References: <20260702155118.667618796@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.12-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: Quentin Schulz 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 a860cb54658a3b..8f9dc2f4891ff5 100644 --- a/fs/eventpoll.c +++ b/fs/eventpoll.c @@ -827,7 +827,7 @@ 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