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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 597BCCDB47E for ; Fri, 13 Oct 2023 12:28:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231784AbjJMM26 (ORCPT ); Fri, 13 Oct 2023 08:28:58 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48390 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231706AbjJMM2z (ORCPT ); Fri, 13 Oct 2023 08:28:55 -0400 Received: from out-208.mta1.migadu.com (out-208.mta1.migadu.com [95.215.58.208]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3CAB2A9 for ; Fri, 13 Oct 2023 05:28:53 -0700 (PDT) Message-ID: <6f155aa3-8e75-40c5-9686-cad9f9ac0d81@linux.dev> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1697200130; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=2WcNCjqTrYw4w54tLjxx6lE9IzfrwCwu1B6SvV0EX7g=; b=KOpng4ZEFIK9KUv/RZtB4K4gKz8qixI4WpNdHbuA+KLrvn4K2ZKEsO+WkPb2YlwQ02q61d AdodBsY7zO+K1O/MgtDWK3rAWoVfySj3hz51gJG1l4C26slGUbhckaadgk+2wirdAv5iHr xHatuR1r6JR7HOWkzT3wUjxrzqODy0o= Date: Fri, 13 Oct 2023 20:28:39 +0800 MIME-Version: 1.0 Subject: Re: [PATCH 1/1] RDMA/rxe: Fix blktests srp lead kernel panic with 64k page size To: "Daisuke Matsuda (Fujitsu)" , 'Zhu Yanjun' , "yi.zhang@redhat.com" Cc: "jgg@ziepe.ca" , "leon@kernel.org" , "linux-rdma@vger.kernel.org" , "zyjzyj2000@gmail.com" References: <20231013011803.70474-1-yanjun.zhu@intel.com> X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Zhu Yanjun In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org 在 2023/10/13 20:01, Daisuke Matsuda (Fujitsu) 写道: > On Fri, Oct 13, 2023 10:18 AM Zhu Yanjun wrote: >> From: Zhu Yanjun >> >> The page_size of mr is set in infiniband core originally. In the commit >> 325a7eb85199 ("RDMA/rxe: Cleanup page variables in rxe_mr.c"), the >> page_size is also set. Sometime this will cause conflict. > > I appreciate your prompt action, but I do not think this commit deals with > the root cause. I agree that the problem lies in rxe driver, but what is wrong > with assigning actual page size to ibmr.page_size? Please check the source code. ibmr.page_size is assigned in infiniband/core. And then it is assigned in rxe. When the 2 are different, the problem will occur. Please add logs to infiniband/core and rxe to check them. Zhu Yanjun > > IMO, the problem comes from the device attribute of rxe driver, which is used > in ulp/srp layer to calculate the page_size. > ===== > static int srp_add_one(struct ib_device *device) > { > struct srp_device *srp_dev; > struct ib_device_attr *attr = &device->attrs; > <...> > /* > * Use the smallest page size supported by the HCA, down to a > * minimum of 4096 bytes. We're unlikely to build large sglists > * out of smaller entries. > */ > mr_page_shift = max(12, ffs(attr->page_size_cap) - 1); > srp_dev->mr_page_size = 1 << mr_page_shift; > ===== > On initialization of srp driver, mr_page_size is calculated here. > Note that the device attribute is used to calculate the value of page shift > when the device is trying to use a page size larger than 4096. Since Yi specified > CONFIG_ARM64_64K_PAGES, the system naturally met the condition. > > ===== > static int srp_map_finish_fr(struct srp_map_state *state, > struct srp_request *req, > struct srp_rdma_ch *ch, int sg_nents, > unsigned int *sg_offset_p) > { > struct srp_target_port *target = ch->target; > struct srp_device *dev = target->srp_host->srp_dev; > <...> > n = ib_map_mr_sg(desc->mr, state->sg, sg_nents, sg_offset_p, > dev->mr_page_size); > ===== > After that, mr_page_size is presumably passed to ib_core layer. > > ===== > int ib_map_mr_sg(struct ib_mr *mr, struct scatterlist *sg, int sg_nents, > unsigned int *sg_offset, unsigned int page_size) > { > if (unlikely(!mr->device->ops.map_mr_sg)) > return -EOPNOTSUPP; > > mr->page_size = page_size; > > return mr->device->ops.map_mr_sg(mr, sg, sg_nents, sg_offset); > } > EXPORT_SYMBOL(ib_map_mr_sg); > ===== > Consequently, the page size calculated in srp driver is set to ibmr.page_size. > > Coming back to rxe, the device attribute is set here: > ===== > rxe.c > <...> > /* initialize rxe device parameters */ > static void rxe_init_device_param(struct rxe_dev *rxe) > { > rxe->max_inline_data = RXE_MAX_INLINE_DATA; > > rxe->attr.vendor_id = RXE_VENDOR_ID; > rxe->attr.max_mr_size = RXE_MAX_MR_SIZE; > rxe->attr.page_size_cap = RXE_PAGE_SIZE_CAP; > rxe->attr.max_qp = RXE_MAX_QP; > --- > rxe_param.h > <...> > /* default/initial rxe device parameter settings */ > enum rxe_device_param { > RXE_MAX_MR_SIZE = -1ull, > RXE_PAGE_SIZE_CAP = 0xfffff000, > RXE_MAX_QP_WR = DEFAULT_MAX_VALUE, > ===== > rxe_init_device_param() sets the attributes to rxe_dev->attr, and it is later copied > to ib_device->attrs in setup_device()@core/device.c. > See that the page size cap is hardcoded to 4096 bytes. I suspect this led to > incorrect page_size being set to ibmr.page_size, resulting in the kernel crash. > > I think rxe driver is made to be able to handle arbitrary page sizes. > Probably, we can just modify RXE_PAGE_SIZE_CAP to fix the issue. > What do you guys think? > > Thanks, > Daisuke Matsuda >