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 B64094446EA; Tue, 21 Jul 2026 21:08:01 +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=1784668082; cv=none; b=sqjc6X/Rg1CoRvP8bRoTjtKWzMKG05ch+VsRvKMBwo0DRz156NOOF/RxgpXDZDXun8AcLaTEqaw2xfA4SbLkDZXnOe66uzIowkqC7nQbAE7KAn76YTO4c/Hrunwwpb0Jv4YfFti9AP/rJymzYmNlfImdjBXuiXcFyjn36VTaa0Q= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784668082; c=relaxed/simple; bh=tapXgIuXEKW933Y9h2meXcV7aPh1LDtcHsUn3R7u930=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=NcX2abztdr+WGUSuVr1W/WA8DKpuiCEYcXQSImZnuFtta6SeOde9eredebDG3sfYer7xa+k4zeJlxCyOyzbdTpYctBUD9ABgPeKT00AjZgdZ/o7sSFi4t2kYPJ7xJE+cwbaikFF4mn64oL1h5jMK80asSn9T+hB4z4O6nLfhokg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=sSIHpEUm; 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="sSIHpEUm" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 218041F000E9; Tue, 21 Jul 2026 21:08:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1784668081; bh=VVarg6RYx9kvedrBmmvQJtjaXp0KxM5GH8B08wSS3hs=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=sSIHpEUmxVrYuVElv570AHp/YBtZy7wXeoK5+km7qPVV1y1Q/4s5NJaG/MPOsrrDv hWk/zhIfEwe8Ck+MqwZ97CvysggrHUaTPqEkiOL+TC62Ol4Wxc1C7MdSVZLGw11giv OUq/+7yeW3yFfJynWu/VBzUG8XvyRs80MteHtn9Q= From: Greg Kroah-Hartman To: stable@vger.kernel.org, carnil@debian.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, "Christian Brauner (Amutable)" , Quentin Schulz , Wentao Guan Subject: [PATCH 6.1 0040/1067] eventpoll: use hlist_is_singular_node() in __ep_remove() Date: Tue, 21 Jul 2026 17:10:41 +0200 Message-ID: <20260721152425.453040452@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260721152424.521567757@linuxfoundation.org> References: <20260721152424.521567757@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 6.1-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: Wentao Guan Signed-off-by: Greg Kroah-Hartman --- fs/eventpoll.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/fs/eventpoll.c +++ b/fs/eventpoll.c @@ -745,7 +745,7 @@ static bool __ep_remove(struct eventpoll 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)) {