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=-15.8 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 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 5DA42C4338F for ; Mon, 2 Aug 2021 14:25:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 46C7560EC0 for ; Mon, 2 Aug 2021 14:25:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234291AbhHBOZ1 (ORCPT ); Mon, 2 Aug 2021 10:25:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46504 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234477AbhHBOZZ (ORCPT ); Mon, 2 Aug 2021 10:25:25 -0400 Received: from mail-lj1-x233.google.com (mail-lj1-x233.google.com [IPv6:2a00:1450:4864:20::233]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 82164C06179E for ; Mon, 2 Aug 2021 07:24:51 -0700 (PDT) Received: by mail-lj1-x233.google.com with SMTP id h11so24081694ljo.12 for ; Mon, 02 Aug 2021 07:24:51 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ionos.com; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=qrmiLmi2xNNwXIdoYlyYaNajS4xKGOSDHbZhpT0dlNo=; b=cVTDCehRXtLX+T7u+I6Hmy5WhpfdEpHJvkAD+Nd/dFmEn0tGWGM4hkYfr2N7Panr61 gTL/cQyEJ5NMHZuUuQzbEOY4jyzHYnZaF4RWK9G3Se15Tlrt5iUBU1e5ez7WG3o7puQi 9a3LdSXAurpr2Xk+98gG/JJm9eW1qHuTFubROoKb7kVNwcgnxWw+A8Q4hIf3+yy0HAQk fiKMoVPfiGCjrdNoXgxk2cn51hxj06/RMNd83yjVVmV19Ywzj3n4x1Af3sdY558clwV/ PrAXhYaQCUfCputbpmlcAwq3zbmrfJ8GEeP2VNm5Dsv84n+Bjo2EXiWpUpg8GKIh9dbI xovA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=qrmiLmi2xNNwXIdoYlyYaNajS4xKGOSDHbZhpT0dlNo=; b=pvIurPt1sHQIfbax8YUOzC81Tk7aJLQts6aAE7G5SMqB4lzQBsEicnWdE7V4OoWcCR 29ZhOwhw+MN4OZBRaTgTbW9DBfygpnQwiRpSJIR9sqh4AOYr5LYrFL7vGWVyDizgenem 3utVT+mLOuAYc71z/pAKqc5EhiMSaZK/rChjsFv1IPHGhiUH3CvYBd3ItmnfbGRXctDD wjX71ieEF4P7c7SWECxjvNJrgR18M6HO9OeB1FtCchgVsn1036ONWrHXDlX2O+VKR6YJ 2NoMPcJ9EXexmaSlbyN8LkE/HVivc/ESv+SXwk+Gdx01Y9LOTtdniRRZjiWQ9iEknwNM Qypg== X-Gm-Message-State: AOAM530A+mG0wF5OSdUtJGSR+qzGhMsoxtAIDknqQEtaA5tMXlkJDcCr PxKgz86BMFjQEZ8y3Di01ONhTKaGn8K0mApYzg4zQw== X-Google-Smtp-Source: ABdhPJwvNVB6aW4kCssQIcvFZdhEoCdZroGY4g3iv/xipMRqXy/QqF7jQGTxPuDlyA45RuTAqslyU/6LwQIxT3fMqDs= X-Received: by 2002:a2e:96cb:: with SMTP id d11mr11385149ljj.221.1627914289901; Mon, 02 Aug 2021 07:24:49 -0700 (PDT) MIME-Version: 1.0 References: <20210730131832.118865-1-jinpu.wang@ionos.com> <20210730131832.118865-3-jinpu.wang@ionos.com> In-Reply-To: From: Haris Iqbal Date: Mon, 2 Aug 2021 16:24:39 +0200 Message-ID: Subject: Re: [PATCH for-next 02/10] RDMA/rtrs-srv: Prevent sysfs error with path name "ctl" To: Leon Romanovsky Cc: Jack Wang , RDMA mailing list , Bart Van Assche , Doug Ledford , Jason Gunthorpe , Gioh Kim Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org On Mon, Aug 2, 2021 at 8:47 AM Leon Romanovsky wrote: > > On Fri, Jul 30, 2021 at 03:18:24PM +0200, Jack Wang wrote: > > From: Gioh Kim > > > > If the client tries to create a path with name "ctl", > > the server tries to creates /sys/devices/virtual/rtrs-server/ctl/. > > Then server generated below error because there is already ctl directory > > which manages some setup of the server. > > > > sysfs: cannot create duplicate filename '/devices/virtual/rtrs-server/ctl' > > Workqueue: ib-comp-wq ib_cq_poll_work [ib_core] > > Call Trace: > > dump_stack+0x50/0x63 > > sysfs_warn_dup.cold+0x17/0x24 > > sysfs_create_dir_ns+0xb6/0xd0 > > kobject_add_internal+0xa6/0x2a0 > > kobject_add+0x7e/0xb0 > > ? _cond_resched+0x15/0x30 > > device_add+0x121/0x640 > > rtrs_srv_create_sess_files+0x18f/0x1f0 [rtrs_server] > > ? __alloc_pages_nodemask+0x16c/0x2b0 > > ? kmalloc_order+0x7c/0x90 > > ? kmalloc_order_trace+0x1d/0xa0 > > ? rtrs_iu_alloc+0x17e/0x1bf [rtrs_core] > > rtrs_srv_info_req_done+0x417/0x5b0 [rtrs_server] > > ? __switch_to_asm+0x40/0x70 > > __ib_process_cq+0x76/0xd0 [ib_core] > > ib_cq_poll_work+0x26/0x80 [ib_core] > > process_one_work+0x1df/0x3a0 > > worker_thread+0x4a/0x3c0 > > kthread+0xfb/0x130 > > ? process_one_work+0x3a0/0x3a0 > > ? kthread_park+0x90/0x90 > > ret_from_fork+0x1f/0x40 > > kobject_add_internal failed for ctl with -EEXIST, don't try to register things with the same name in the same directory. > > rtrs_server L178: device_add(): -17 > > > > This patch checks the path name and disconnect on server to prevent > > the kernel error. > > > > Signed-off-by: Gioh Kim > > Signed-off-by: Jack Wang > > --- > > drivers/infiniband/ulp/rtrs/rtrs-srv.c | 8 ++++++++ > > 1 file changed, 8 insertions(+) > > > > diff --git a/drivers/infiniband/ulp/rtrs/rtrs-srv.c b/drivers/infiniband/ulp/rtrs/rtrs-srv.c > > index cd9a4ccf4c28..b814a6052cf1 100644 > > --- a/drivers/infiniband/ulp/rtrs/rtrs-srv.c > > +++ b/drivers/infiniband/ulp/rtrs/rtrs-srv.c > > @@ -758,6 +758,14 @@ static bool exist_sessname(struct rtrs_srv_ctx *ctx, > > struct rtrs_srv_sess *sess; > > bool found = false; > > > > + /* > > + * Session name "ct" is not allowed because > > + * /sys/devices/virtual/rtrs-server/ctl already exists > > + * for setup management. > > + */ > > + if (!strcmp(sessname, "ctl")) > > + return true; > > Why does it have special treatment? rtrs-server creates a folder named ctl when the module is modprob'ed. When a session is established, a folder of the session name is created at the same location, which would hold sysfs entries such as clt_hostname, path details, queue_depth, etc. Due to this conflict of names, creation of session with that name is not possible. So this gracefully fails the connection establishment instead of a stack trace. > And what will happen if user supplies "." or ".."? Weirdly enough, this succeeds. I tried, and the session creation succeeds, and there is a hidden entry in the rtrs-server folder, but it cannot be accessed through bash. > Does rtrs receive this session name from the other side in the network? Yes. This string is entered by the user while creating the session. > > Thanks