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 31EACC433F5 for ; Mon, 13 Dec 2021 10:13:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238671AbhLMKLy (ORCPT ); Mon, 13 Dec 2021 05:11:54 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34460 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242831AbhLMKIy (ORCPT ); Mon, 13 Dec 2021 05:08:54 -0500 Received: from sin.source.kernel.org (sin.source.kernel.org [IPv6:2604:1380:40e1:4800::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5BD7FC08EA76; Mon, 13 Dec 2021 01:53:22 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by sin.source.kernel.org (Postfix) with ESMTPS id A7E19CE0DEF; Mon, 13 Dec 2021 09:53:20 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 521B0C00446; Mon, 13 Dec 2021 09:53:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1639389198; bh=NEQJNdKR5JoGf6gQvZzjS89qgZG3Wgn14DWga/h9BXw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=YvTTq7xlxqy0oQ2Obfwdgrp7e+NVy5GD09V0gY72xqEMUgSRig1w1UprSOnwkO6r9 2sZMvDfxeyW51N9rQqd0BZMw8PlgPKDz+TTC9FV+9GDmJuzQ8d+cWq/7akA6now6Vo kILsgPuxG0TCm791qeHwyS7GpzIhoaimeyMyfvrg= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Mike Marciniszyn , Dennis Dalessandro , Jason Gunthorpe Subject: [PATCH 5.15 018/171] IB/hfi1: Insure use of smp_processor_id() is preempt disabled Date: Mon, 13 Dec 2021 10:28:53 +0100 Message-Id: <20211213092945.695040078@linuxfoundation.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20211213092945.091487407@linuxfoundation.org> References: <20211213092945.091487407@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Mike Marciniszyn commit b6d57e24ce6cc3df8a8845e1b193e88a65d501b1 upstream. The following BUG has just surfaced with our 5.16 testing: BUG: using smp_processor_id() in preemptible [00000000] code: mpicheck/1581081 caller is sdma_select_user_engine+0x72/0x210 [hfi1] CPU: 0 PID: 1581081 Comm: mpicheck Tainted: G S 5.16.0-rc1+ #1 Hardware name: Intel Corporation S2600WT2R/S2600WT2R, BIOS SE5C610.86B.01.01.0016.033120161139 03/31/2016 Call Trace: dump_stack_lvl+0x33/0x42 check_preemption_disabled+0xbf/0xe0 sdma_select_user_engine+0x72/0x210 [hfi1] ? _raw_spin_unlock_irqrestore+0x1f/0x31 ? hfi1_mmu_rb_insert+0x6b/0x200 [hfi1] hfi1_user_sdma_process_request+0xa02/0x1120 [hfi1] ? hfi1_write_iter+0xb8/0x200 [hfi1] hfi1_write_iter+0xb8/0x200 [hfi1] do_iter_readv_writev+0x163/0x1c0 do_iter_write+0x80/0x1c0 vfs_writev+0x88/0x1a0 ? recalibrate_cpu_khz+0x10/0x10 ? ktime_get+0x3e/0xa0 ? __fget_files+0x66/0xa0 do_writev+0x65/0x100 do_syscall_64+0x3a/0x80 Fix this long standing bug by moving the smp_processor_id() to after the rcu_read_lock(). The rcu_read_lock() implicitly disables preemption. Link: https://lore.kernel.org/r/20211129191958.101968.87329.stgit@awfm-01.cornelisnetworks.com Cc: stable@vger.kernel.org Fixes: 0cb2aa690c7e ("IB/hfi1: Add sysfs interface for affinity setup") Signed-off-by: Mike Marciniszyn Signed-off-by: Dennis Dalessandro Signed-off-by: Jason Gunthorpe Signed-off-by: Greg Kroah-Hartman --- drivers/infiniband/hw/hfi1/sdma.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/drivers/infiniband/hw/hfi1/sdma.c +++ b/drivers/infiniband/hw/hfi1/sdma.c @@ -838,8 +838,8 @@ struct sdma_engine *sdma_select_user_eng if (current->nr_cpus_allowed != 1) goto out; - cpu_id = smp_processor_id(); rcu_read_lock(); + cpu_id = smp_processor_id(); rht_node = rhashtable_lookup(dd->sdma_rht, &cpu_id, sdma_rht_params);