From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-18.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 52B5CC433B4 for ; Sat, 24 Apr 2021 23:27:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 35F1461425 for ; Sat, 24 Apr 2021 23:27:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230160AbhDXX1t (ORCPT ); Sat, 24 Apr 2021 19:27:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45742 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230079AbhDXX1t (ORCPT ); Sat, 24 Apr 2021 19:27:49 -0400 Received: from hr2.samba.org (hr2.samba.org [IPv6:2a01:4f8:192:486::2:0]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A8EF7C061574 for ; Sat, 24 Apr 2021 16:27:09 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=samba.org; s=42; h=Message-Id:Date:Cc:To:From; bh=JDlyLBAXYb24r8TzVjtzv4ixia6JJkHE2lBbOkTwT94=; b=d3MvO3CItDrMEHmNDiuAiFkcQ3 XrmDpZaN0jQw4Bx+QdoPT3YvDVBhjWrFIaXogc0OCb0wr/XKpzty7QvWoUlIXSwY7YU8XJHiu/A1L bTfFjwde8FlfDbg4fhm15efhYbF8OFB98eLGF6Y4guQnx+2qRyOuXrmQHuQ68RQ8l3AcIbuBk9NH+ lEMOyc96MrBZ/sUCaWEukdoNHRYI25t8gCSB97VlG7w3WXBx1FwitbtIT3OZpkNmQZxyrZuD7DZH3 WQitsr3gA3WmTCO8LNapXHCloCI5jRYdokVHJWtCogQKj1jpyRozYxuIXCxNdg/YSwrwSYE0RiXIL izENlhF9wibBXgqYLCmCiX048f+89b0vPv2RqCLHCSacgHl0svZAIGdA0s3Phn6LrC68+vWSbqF6J M6MyhsKIqlRWix/0LwG8Jei6rne+tZTEMdiPywefZ7Lf1IGNT5G8DFSsa9Q1tgxIgU6yvzM7waEvc FcVTnRO+f6THqk/gmllAR/5D; Received: from [127.0.0.2] (localhost [127.0.0.1]) by hr2.samba.org with esmtpsa (TLS1.3:ECDHE_RSA_CHACHA20_POLY1305:256) (Exim) id 1laRg3-0007XR-Lr; Sat, 24 Apr 2021 23:27:07 +0000 From: Stefan Metzmacher To: Jens Axboe , io-uring@vger.kernel.org Cc: Stefan Metzmacher Subject: [PATCH v3 6/6] io_uring: warn about future set_task_comm() overflows. Date: Sun, 25 Apr 2021 01:26:08 +0200 Message-Id: X-Mailer: git-send-email 2.25.1 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org Signed-off-by: Stefan Metzmacher --- fs/io_uring.c | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index 856289b13488..dba4ceea80ee 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -7932,7 +7932,19 @@ static int io_sq_offload_create(struct io_ring_ctx *ctx, goto err_sqpoll; } - snprintf(tsk_comm, sizeof(tsk_comm), "iou-sqp-%d", sqd->task_pid); + /* + * The limit value of pid_max_max/PID_MAX_LIMIT + * is 4 * 1024 * 1024 = 4194304. + * + * TASK_COMM_LEN is 16, so we have 15 chars to fill. + * + * With "iou-sqp-4194304" we just fit into 15 chars. + * If that ever changes we may better add some special + * handling for PF_IO_WORKER in proc_task_name(), as that + * allows up to 63 chars. + */ + WARN_ON(snprintf(tsk_comm, sizeof(tsk_comm), + "iou-sqp-%d", sqd->task_pid) >= sizeof(tsk_comm)); set_task_comm(tsk, tsk_comm); if (sqd->sq_cpu != -1) -- 2.25.1