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=-6.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 C753AC43381 for ; Fri, 22 Mar 2019 12:40:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8CF962070D for ; Fri, 22 Mar 2019 12:40:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1553258442; bh=jGnQ3aWdcq+TW4612Xeaq2E6PkwCDEbcKFNUikpzpqg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=tdHivi1PaDniZL4lfIFqLLrnq6a6ok2qK3v6j581AUmsH+Z/4o5SFu2VfE8gEZovu Vu2AwD+Jp8gD9XEOb2kTNu5s7OkQ47EXnmJAhvsjmcI67vuAr2EnDlurez9l3IQEMA bpywrDFVaesNZs2Ghbxb6MBe+ws1IbgHPw0azu6Q= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388714AbfCVMkb (ORCPT ); Fri, 22 Mar 2019 08:40:31 -0400 Received: from mail.kernel.org ([198.145.29.99]:44930 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732215AbfCVMG3 (ORCPT ); Fri, 22 Mar 2019 08:06:29 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 64F9F2192D; Fri, 22 Mar 2019 12:06:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1553256388; bh=jGnQ3aWdcq+TW4612Xeaq2E6PkwCDEbcKFNUikpzpqg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=S3hboMcsibKSgNUTrJnjfUOwcI3ejfNcSwwbXovtiDs4BqiPa1oZs+TsVbLMANTvu 8cYOLcS0MK9RLyI+fg+Fd3D0bDoc1LID5Rln/rN7ehaDS8iLYy6aHeFZO9+q4JweEr bZbQPRm1J2iNGG7BPqg7xsy7X3mN45vP7Dxolf6M= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Mike Marciniszyn , "Michael J. Ruhl" , Dennis Dalessandro , Jason Gunthorpe Subject: [PATCH 4.19 188/280] IB/hfi1: Close race condition on user context disable and close Date: Fri, 22 Mar 2019 12:15:41 +0100 Message-Id: <20190322111328.083720941@linuxfoundation.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190322111306.356185024@linuxfoundation.org> References: <20190322111306.356185024@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org 4.19-stable review patch. If anyone has any objections, please let me know. ------------------ From: Michael J. Ruhl commit bc5add09764c123f58942a37c8335247e683d234 upstream. When disabling and removing a receive context, it is possible for an asynchronous event (i.e IRQ) to occur. Because of this, there is a race between cleaning up the context, and the context being used by the asynchronous event. cpu 0 (context cleanup) rc->ref_count-- (ref_count == 0) hfi1_rcd_free() cpu 1 (IRQ (with rcd index)) rcd_get_by_index() lock ref_count+++ <-- reference count race (WARNING) return rcd unlock cpu 0 hfi1_free_ctxtdata() <-- incorrect free location lock remove rcd from array unlock free rcd This race will cause the following WARNING trace: WARNING: CPU: 0 PID: 175027 at include/linux/kref.h:52 hfi1_rcd_get_by_index+0x84/0xa0 [hfi1] CPU: 0 PID: 175027 Comm: IMB-MPI1 Kdump: loaded Tainted: G OE ------------ 3.10.0-957.el7.x86_64 #1 Hardware name: Intel Corporation S2600KP/S2600KP, BIOS SE5C610.86B.11.01.0076.C4.111920150602 11/19/2015 Call Trace: dump_stack+0x19/0x1b __warn+0xd8/0x100 warn_slowpath_null+0x1d/0x20 hfi1_rcd_get_by_index+0x84/0xa0 [hfi1] is_rcv_urgent_int+0x24/0x90 [hfi1] general_interrupt+0x1b6/0x210 [hfi1] __handle_irq_event_percpu+0x44/0x1c0 handle_irq_event_percpu+0x32/0x80 handle_irq_event+0x3c/0x60 handle_edge_irq+0x7f/0x150 handle_irq+0xe4/0x1a0 do_IRQ+0x4d/0xf0 common_interrupt+0x162/0x162 The race can also lead to a use after free which could be similar to: general protection fault: 0000 1 SMP CPU: 71 PID: 177147 Comm: IMB-MPI1 Kdump: loaded Tainted: G W OE ------------ 3.10.0-957.el7.x86_64 #1 Hardware name: Intel Corporation S2600KP/S2600KP, BIOS SE5C610.86B.11.01.0076.C4.111920150602 11/19/2015 task: ffff9962a8098000 ti: ffff99717a508000 task.ti: ffff99717a508000 __kmalloc+0x94/0x230 Call Trace: ? hfi1_user_sdma_process_request+0x9c8/0x1250 [hfi1] hfi1_user_sdma_process_request+0x9c8/0x1250 [hfi1] hfi1_aio_write+0xba/0x110 [hfi1] do_sync_readv_writev+0x7b/0xd0 do_readv_writev+0xce/0x260 ? handle_mm_fault+0x39d/0x9b0 ? pick_next_task_fair+0x5f/0x1b0 ? sched_clock_cpu+0x85/0xc0 ? __schedule+0x13a/0x890 vfs_writev+0x35/0x60 SyS_writev+0x7f/0x110 system_call_fastpath+0x22/0x27 Use the appropriate kref API to verify access. Reorder context cleanup to ensure context removal before cleanup occurs correctly. Cc: stable@vger.kernel.org # v4.14.0+ Fixes: f683c80ca68e ("IB/hfi1: Resolve kernel panics by reference counting receive contexts") Reviewed-by: Mike Marciniszyn Signed-off-by: Michael J. Ruhl Signed-off-by: Dennis Dalessandro Signed-off-by: Jason Gunthorpe Signed-off-by: Greg Kroah-Hartman --- drivers/infiniband/hw/hfi1/hfi.h | 2 +- drivers/infiniband/hw/hfi1/init.c | 14 +++++++++----- 2 files changed, 10 insertions(+), 6 deletions(-) --- a/drivers/infiniband/hw/hfi1/hfi.h +++ b/drivers/infiniband/hw/hfi1/hfi.h @@ -1425,7 +1425,7 @@ void hfi1_init_pportdata(struct pci_dev struct hfi1_devdata *dd, u8 hw_pidx, u8 port); void hfi1_free_ctxtdata(struct hfi1_devdata *dd, struct hfi1_ctxtdata *rcd); int hfi1_rcd_put(struct hfi1_ctxtdata *rcd); -void hfi1_rcd_get(struct hfi1_ctxtdata *rcd); +int hfi1_rcd_get(struct hfi1_ctxtdata *rcd); struct hfi1_ctxtdata *hfi1_rcd_get_by_index_safe(struct hfi1_devdata *dd, u16 ctxt); struct hfi1_ctxtdata *hfi1_rcd_get_by_index(struct hfi1_devdata *dd, u16 ctxt); --- a/drivers/infiniband/hw/hfi1/init.c +++ b/drivers/infiniband/hw/hfi1/init.c @@ -213,12 +213,12 @@ static void hfi1_rcd_free(struct kref *k struct hfi1_ctxtdata *rcd = container_of(kref, struct hfi1_ctxtdata, kref); - hfi1_free_ctxtdata(rcd->dd, rcd); - spin_lock_irqsave(&rcd->dd->uctxt_lock, flags); rcd->dd->rcd[rcd->ctxt] = NULL; spin_unlock_irqrestore(&rcd->dd->uctxt_lock, flags); + hfi1_free_ctxtdata(rcd->dd, rcd); + kfree(rcd); } @@ -241,10 +241,13 @@ int hfi1_rcd_put(struct hfi1_ctxtdata *r * @rcd: pointer to an initialized rcd data structure * * Use this to get a reference after the init. + * + * Return : reflect kref_get_unless_zero(), which returns non-zero on + * increment, otherwise 0. */ -void hfi1_rcd_get(struct hfi1_ctxtdata *rcd) +int hfi1_rcd_get(struct hfi1_ctxtdata *rcd) { - kref_get(&rcd->kref); + return kref_get_unless_zero(&rcd->kref); } /** @@ -324,7 +327,8 @@ struct hfi1_ctxtdata *hfi1_rcd_get_by_in spin_lock_irqsave(&dd->uctxt_lock, flags); if (dd->rcd[ctxt]) { rcd = dd->rcd[ctxt]; - hfi1_rcd_get(rcd); + if (!hfi1_rcd_get(rcd)) + rcd = NULL; } spin_unlock_irqrestore(&dd->uctxt_lock, flags);