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 43230ECAAD1 for ; Thu, 1 Sep 2022 12:27:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233550AbiIAM1i (ORCPT ); Thu, 1 Sep 2022 08:27:38 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45440 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233542AbiIAM1L (ORCPT ); Thu, 1 Sep 2022 08:27:11 -0400 Received: from corp-front10-corp.i.nease.net (corp-front10-corp.i.nease.net [42.186.62.104]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6BE361299E6; Thu, 1 Sep 2022 05:26:56 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=corp.netease.com; s=s210401; h=Received:From:To:Cc:Subject: Date:Message-Id:In-Reply-To:References:MIME-Version: Content-Transfer-Encoding; bh=dsgO1pTu9V7tw3lv2GpNyG8eLdMIvx7w+4 467mn+OLA=; b=Yg8vihwjRltNbFq4Jf+1fU/nf2ydsOzZhBEeXfnqzBWvszmrT7 2smHvwnjcId61VSlflRmGAbjM9q+ZNuYhQXo+d1tLkaI6qtqJ1RhHC3FugQHSGIK iiiFm7diRA/fcH0YbOw5Y0N8mHmOQ7u/sQ9MW5U+rGvHJcRMSqh9dqghw= Received: from pubt1-k8s74.yq.163.org (unknown [115.238.122.38]) by corp-front10-corp.i.nease.net (Coremail) with SMTP id aIG_CgCn9ef5pBBjilwiAA--.40527S2; Thu, 01 Sep 2022 20:26:33 +0800 (HKT) From: liuyacan@corp.netease.com To: wenjia@linux.ibm.com, alibuda@linux.alibaba.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, liuyacan@corp.netease.com, netdev@vger.kernel.org, pabeni@redhat.com, tonylu@linux.alibaba.com, ubraun@linux.vnet.ibm.com, wintera@linux.ibm.com Subject: Re: [PATCH net v4] net/smc: Fix possible access to freed memory in link clear Date: Thu, 1 Sep 2022 20:26:33 +0800 Message-Id: <20220901122633.1657859-1-liuyacan@corp.netease.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <04dbfe8a-a023-c6cf-8d20-965859c1d33a@linux.ibm.com> References: <04dbfe8a-a023-c6cf-8d20-965859c1d33a@linux.ibm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CM-TRANSID: aIG_CgCn9ef5pBBjilwiAA--.40527S2 X-Coremail-Antispam: 1UD129KBjvJXoW3ArW8Ww18WFW7uFy7Kw4kZwb_yoW3Gw1fpF s7WF47CF48Xr1UXFn5AF1xZF1Yq3W2yFy8Gr929F9YyFnxJw18JF1Sgry2vFyDAr4qg3WI v348Xw1Ikrs8XaDanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUXab7IF0VCFI7km07C26c804VAKzcIF0wAFF20E14v26r4j6ryU M7CY07I20VC2zVCF04k26cxKx2IYs7xG6rWj6s0DM7CIcVAFz4kK6r1j6r18M28lY4IEw2 IIxxk0rwA2F7IY1VAKz4vEj48ve4kI8wA2z4x0Y4vE2Ix0cI8IcVAFwI0_tr0E3s1l84AC jcxK6xIIjxv20xvEc7CjxVAFwI0_Cr1j6rxdM28EF7xvwVC2z280aVAFwI0_GcCE3s1l84 ACjcxK6I8E87Iv6xkF7I0E14v26rxl6s0DM2kK67ZEXf0FJ3sC6x9vy-n0Xa0_Xr1Utr1k JwI_Jr4ln4vEF7Iv6F18KVAqrcv_GVWUtr1rJF1ln4vEF7Iv6F18KVAqrcv_XVWUtr1rJF 1ln4vE4IxY62xKV4CY8xCE548m6r4UJryUGwAa7VCY0VAaVVAqrcv_Jw1UWr13M2AIxVAI cxkEcVAq07x20xvEncxIr21l57IF6s8CjcxG0xyl5I8CrVACY4xI64kE6c02F40Ex7xfMc Ij6xIIjxv20xvE14v26r1j6r18McIj6I8E87Iv67AKxVWUJVW8JwAm72CE4IkC6x0Yz7v_ Jr0_Gr1lF7xvr2IYc2Ij64vIr41lF7I21c0EjII2zVCS5cI20VAGYxC7M4IIrI8v6xkF7I 0E8cxan2IY04v7M4kE6xkIj40Ew7xC0wCjxxvEw4Wlc2IjII80xcxEwVAKI48JMxAIw28I cxkI7VAKI48JMxCjnVAK0II2c7xJMxC20s026xCaFVCjc4AY6r1j6r4UMxCIbVAxMI8I3I 0E5I8CrVAFwI0_Jr0_Jr4lx2IqxVCjr7xvwVAFwI0_JrI_JrWlx4CE17CEb7AF67AKxVWU tVW8ZwCIc40Y0x0EwIxGrwCI42IY6xIIjxv20xvE14v26r1j6r1xMIIF0xvE2Ix0cI8IcV CY1x0267AKxVW8JVWxJwCI42IY6xAIw20EY4v20xvaj40_Jr0_JF4lIxAIcVC2z280aVAF wI0_Jr0_Gr1lIxAIcVC2z280aVCY1x0267AKxVW8JVW8JrUvcSsGvfC2KfnxnUUI43ZEXa 7sRiE_M7UUUUU== X-CM-SenderInfo: 5olx5txfdqquhrush05hwht23hof0z/1tbiBQAQCVt77zCWdAATsS Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org > > 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_free_link(lnk); > > smc_ib_destroy_queue_pair(lnk); > > smc_ib_dealloc_protection_domain(lnk); > > diff --git a/net/smc/smc_core.h b/net/smc/smc_core.h > > index fe8b524ad..285f9bd8e 100644 > > --- a/net/smc/smc_core.h > > +++ b/net/smc/smc_core.h > > @@ -115,8 +115,10 @@ struct smc_link { > > dma_addr_t wr_rx_dma_addr; /* DMA address of wr_rx_bufs */ > > dma_addr_t wr_rx_v2_dma_addr; /* DMA address of v2 rx buf*/ > > u64 wr_rx_id; /* seq # of last recv WR */ > > + u64 wr_rx_id_compl; /* seq # of last completed WR */ > > u32 wr_rx_cnt; /* number of WR recv buffers */ > > unsigned long wr_rx_tstamp; /* jiffies when last buf rx */ > > + wait_queue_head_t wr_rx_empty_wait; /* wait for RQ empty */ > > > > struct ib_reg_wr wr_reg; /* WR register memory region */ > > wait_queue_head_t wr_reg_wait; /* wait for wr_reg result */ > > diff --git a/net/smc/smc_wr.c b/net/smc/smc_wr.c > > index 26f8f240d..bc8793803 100644 > > --- a/net/smc/smc_wr.c > > +++ b/net/smc/smc_wr.c > > @@ -454,6 +454,7 @@ static inline void smc_wr_rx_process_cqes(struct ib_wc wc[], int num) > > > > for (i = 0; i < num; i++) { > > link = wc[i].qp->qp_context; > > + link->wr_rx_id_compl = wc[i].wr_id; > > if (wc[i].status == IB_WC_SUCCESS) { > > link->wr_rx_tstamp = jiffies; > > smc_wr_rx_demultiplex(&wc[i]); > > @@ -465,6 +466,8 @@ static inline void smc_wr_rx_process_cqes(struct ib_wc wc[], int num) > > case IB_WC_RNR_RETRY_EXC_ERR: > > case IB_WC_WR_FLUSH_ERR: > > smcr_link_down_cond_sched(link); > > + if (link->wr_rx_id_compl == link->wr_rx_id) > > + wake_up(&link->wr_rx_empty_wait); > > break; > > default: > > smc_wr_rx_post(link); /* refill WR RX */ > > @@ -631,6 +634,11 @@ static void smc_wr_init_sge(struct smc_link *lnk) > > lnk->wr_reg.access = IB_ACCESS_LOCAL_WRITE | IB_ACCESS_REMOTE_WRITE; > > } > > > > +void smc_wr_drain_cq(struct smc_link *lnk) > > +{ > > + wait_event(lnk->wr_rx_empty_wait, lnk->wr_rx_id_compl == lnk->wr_rx_id); > > +} > > + > > void smc_wr_free_link(struct smc_link *lnk) > > { > > struct ib_device *ibdev; > > @@ -889,6 +897,7 @@ int smc_wr_create_link(struct smc_link *lnk) > > atomic_set(&lnk->wr_tx_refcnt, 0); > > init_waitqueue_head(&lnk->wr_reg_wait); > > atomic_set(&lnk->wr_reg_refcnt, 0); > > + init_waitqueue_head(&lnk->wr_rx_empty_wait); > > return rc; > > > > dma_unmap: > > diff --git a/net/smc/smc_wr.h b/net/smc/smc_wr.h > > index a54e90a11..5ca5086ae 100644 > > --- a/net/smc/smc_wr.h > > +++ b/net/smc/smc_wr.h > > @@ -101,6 +101,7 @@ static inline int smc_wr_rx_post(struct smc_link *link) > > int smc_wr_create_link(struct smc_link *lnk); > > int smc_wr_alloc_link_mem(struct smc_link *lnk); > > int smc_wr_alloc_lgr_mem(struct smc_link_group *lgr); > > +void smc_wr_drain_cq(struct smc_link *lnk); > > void smc_wr_free_link(struct smc_link *lnk); > > void smc_wr_free_link_mem(struct smc_link *lnk); > > void smc_wr_free_lgr_mem(struct smc_link_group *lgr); > > Thank you @Yacan for the effort to improve our code! And Thank you @Tony > for such valuable suggestions and testing! > I like the modification of this version. However, this is not a fix > patch to upstream, since the patches "[PATCH net-next v2 00/10] optimize > the parallelism of SMC-R connections" are still not applied. My > sugguestions: > - Please talk to the author (D. Wythe ) of > those patches I mentioned above, and ask if he can take your patch as a > part of the patch serie > - Fix patches should go to net-next > - Please send always send your new version separately, rather than as > reply to your previous version. That makes people confused. @Wenjia, Thanks a lot for your suggestions and guidance ! @D. Wythe, Can you include this patch in your series of patches if it is convenient? Regards, Yacan