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 56B31ECAAD3 for ; Sun, 4 Sep 2022 15:58:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234697AbiIDP6Z (ORCPT ); Sun, 4 Sep 2022 11:58:25 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51036 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234631AbiIDP6X (ORCPT ); Sun, 4 Sep 2022 11:58:23 -0400 Received: from out30-130.freemail.mail.aliyun.com (out30-130.freemail.mail.aliyun.com [115.124.30.130]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DB1642F38E; Sun, 4 Sep 2022 08:58:15 -0700 (PDT) X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R101e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=ay29a033018045192;MF=tonylu@linux.alibaba.com;NM=1;PH=DS;RN=12;SR=0;TI=SMTPD_---0VOGfxpk_1662307089; Received: from localhost(mailfrom:tonylu@linux.alibaba.com fp:SMTPD_---0VOGfxpk_1662307089) by smtp.aliyun-inc.com; Sun, 04 Sep 2022 23:58:10 +0800 Date: Sun, 4 Sep 2022 23:58:09 +0800 From: Tony Lu To: liuyacan@corp.netease.com Cc: davem@davemloft.net, edumazet@google.com, kgraul@linux.ibm.com, kuba@kernel.org, linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org, netdev@vger.kernel.org, ubraun@linux.vnet.ibm.com, pabeni@redhat.com, wenjia@linux.ibm.com, wintera@linux.ibm.com Subject: Re: [PATCH net v4] net/smc: Fix possible access to freed memory in link clear Message-ID: Reply-To: Tony Lu References: <20220831155303.1758868-1-liuyacan@corp.netease.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220831155303.1758868-1-liuyacan@corp.netease.com> Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Wed, Aug 31, 2022 at 11:53:03PM +0800, liuyacan@corp.netease.com wrote: > From: Yacan Liu > > After modifying the QP to the Error state, all RX WR would be completed > with WC in IB_WC_WR_FLUSH_ERR status. Current implementation does not > wait for it is done, but destroy the QP and free the link group directly. > So there is a risk that accessing the freed memory in tasklet context. > > Here is a crash example: > > BUG: unable to handle page fault for address: ffffffff8f220860 > #PF: supervisor write access in kernel mode > #PF: error_code(0x0002) - not-present page > PGD f7300e067 P4D f7300e067 PUD f7300f063 PMD 8c4e45063 PTE 800ffff08c9df060 > Oops: 0002 [#1] SMP PTI > CPU: 1 PID: 0 Comm: swapper/1 Kdump: loaded Tainted: G S OE 5.10.0-0607+ #23 > Hardware name: Inspur NF5280M4/YZMB-00689-101, BIOS 4.1.20 07/09/2018 > RIP: 0010:native_queued_spin_lock_slowpath+0x176/0x1b0 > Code: f3 90 48 8b 32 48 85 f6 74 f6 eb d5 c1 ee 12 83 e0 03 83 ee 01 48 c1 e0 05 48 63 f6 48 05 00 c8 02 00 48 03 04 f5 00 09 98 8e <48> 89 10 8b 42 08 85 c0 75 09 f3 90 8b 42 08 85 c0 74 f7 48 8b 32 > RSP: 0018:ffffb3b6c001ebd8 EFLAGS: 00010086 > RAX: ffffffff8f220860 RBX: 0000000000000246 RCX: 0000000000080000 > RDX: ffff91db1f86c800 RSI: 000000000000173c RDI: ffff91db62bace00 > RBP: ffff91db62bacc00 R08: 0000000000000000 R09: c00000010000028b > R10: 0000000000055198 R11: ffffb3b6c001ea58 R12: ffff91db80e05010 > R13: 000000000000000a R14: 0000000000000006 R15: 0000000000000040 > FS: 0000000000000000(0000) GS:ffff91db1f840000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: ffffffff8f220860 CR3: 00000001f9580004 CR4: 00000000003706e0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > Call Trace: > > _raw_spin_lock_irqsave+0x30/0x40 > mlx5_ib_poll_cq+0x4c/0xc50 [mlx5_ib] > smc_wr_rx_tasklet_fn+0x56/0xa0 [smc] > tasklet_action_common.isra.21+0x66/0x100 > __do_softirq+0xd5/0x29c > asm_call_irq_on_stack+0x12/0x20 > > do_softirq_own_stack+0x37/0x40 > irq_exit_rcu+0x9d/0xa0 > sysvec_call_function_single+0x34/0x80 > asm_sysvec_call_function_single+0x12/0x20 > > Fixes: bd4ad57718cc ("smc: initialize IB transport incl. PD, MR, QP, CQ, event, WR") > Signed-off-by: Yacan Liu > > --- > Chagen in v4: > -- Remove the rx_drain flag because smc_wr_rx_post() may not have been called. > -- Remove timeout. > Change in v3: > -- Tune commit message (Signed-Off tag, Fixes tag). > Tune code to avoid column length exceeding. > Change in v2: > -- Fix some compile warnings and errors. > --- > net/smc/smc_core.c | 2 ++ > net/smc/smc_core.h | 2 ++ > net/smc/smc_wr.c | 9 +++++++++ > net/smc/smc_wr.h | 1 + > 4 files changed, 14 insertions(+) > > diff --git a/net/smc/smc_core.c b/net/smc/smc_core.c > index ff49a11f5..f92a916e9 100644 > --- a/net/smc/smc_core.c > +++ b/net/smc/smc_core.c > @@ -757,6 +757,7 @@ int smcr_link_init(struct smc_link_group *lgr, struct smc_link *lnk, > lnk->lgr = lgr; > smc_lgr_hold(lgr); /* lgr_put in smcr_link_clear() */ > lnk->link_idx = link_idx; > + lnk->wr_rx_id_compl = 0; > smc_ibdev_cnt_inc(lnk); > smcr_copy_dev_info_to_link(lnk); > atomic_set(&lnk->conn_cnt, 0); > @@ -1269,6 +1270,7 @@ void smcr_link_clear(struct smc_link *lnk, bool log) > smcr_buf_unmap_lgr(lnk); > smcr_rtoken_clear_link(lnk); > smc_ib_modify_qp_error(lnk); > + smc_wr_drain_cq(lnk); smc_wr_drain_cq() can put into smc_wr_free_link(). Since smc_wr_free_link() do the same things together, such as waiting for resources cleaning up about wr. > smc_wr_free_link(lnk); > smc_ib_destroy_queue_pair(lnk); > smc_ib_dealloc_protection_domain(lnk); The patch tested good in our environment. If you are going to send the v5 patch, you can go with my review. Reviewed-by: Tony Lu Cheers, Tony Lu