From patchwork Wed Aug 30 09:41:32 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Xiubo Li X-Patchwork-Id: 9929127 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id B59886022E for ; Wed, 30 Aug 2017 09:41:38 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id AAFF22842E for ; Wed, 30 Aug 2017 09:41:38 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 9F83A28448; Wed, 30 Aug 2017 09:41:38 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id B23792842E for ; Wed, 30 Aug 2017 09:41:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751316AbdH3Jlh (ORCPT ); Wed, 30 Aug 2017 05:41:37 -0400 Received: from cmccmta2.chinamobile.com ([221.176.66.80]:32713 "EHLO cmccmta2.chinamobile.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750835AbdH3Jlg (ORCPT ); Wed, 30 Aug 2017 05:41:36 -0400 Received: from spf.mail.chinamobile.com (unknown[172.16.121.17]) by rmmx-syy-dmz-app07-12007 (RichMail) with SMTP id 2ee759a6884d6d4-e3677; Wed, 30 Aug 2017 17:41:33 +0800 (CST) X-RM-TRANSID: 2ee759a6884d6d4-e3677 X-RM-SPAM-FLAG: 00000000 Received: from localhost.localdomain (unknown[112.25.154.149]) by rmsmtp-syy-appsvr09-12009 (RichMail) with SMTP id 2ee959a6884c224-eaeff; Wed, 30 Aug 2017 17:41:33 +0800 (CST) X-RM-TRANSID: 2ee959a6884c224-eaeff From: lixiubo@cmss.chinamobile.com To: nab@linux-iscsi.org, mchristi@redhat.com Cc: agrover@redhat.com, namei.unix@gmail.com, target-devel@vger.kernel.org, Xiubo Li , Zhang Zhuoyu Subject: [PATCH] tcmu: fix crash when remove the tcmu device Date: Wed, 30 Aug 2017 17:41:32 +0800 Message-Id: <1504086092-17320-1-git-send-email-lixiubo@cmss.chinamobile.com> X-Mailer: git-send-email 1.9.1 Sender: target-devel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: target-devel@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Xiubo Li Before the nl REMOVE msg has been sent to the userspace, the ring's and other resources has been released, but the userspace maybe still using them. And then we can see the crash messages like: ring broken, not handling completions BUG: unable to handle kernel paging request at ffffffffffffffd0 IP: tcmu_handle_completions+0x134/0x2f0 [target_core_user] PGD 11bdc0c067 P4D 11bdc0c067 PUD 11bdc0e067 PMD 0 Oops: 0000 [#1] SMP cmd_id not found, ring is broken RIP: 0010:tcmu_handle_completions+0x134/0x2f0 [target_core_user] RSP: 0018:ffffb8a2d8983d88 EFLAGS: 00010296 RAX: 0000000000000000 RBX: ffffb8a2aaa4e000 RCX: 00000000ffffffff RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000220 R10: 0000000076c71401 R11: ffff8d2e76c713f0 R12: ffffb8a2aad56bc0 R13: 000000000000001c R14: ffff8d2e32c90000 R15: ffff8d2e76c713f0 FS: 00007f411ffff700(0000) GS:ffff8d1e7fdc0000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffffffffd0 CR3: 0000001027070000 CR4: 00000000001406e0 Call Trace: ? tcmu_irqcontrol+0x2a/0x40 [target_core_user] ? uio_write+0x7b/0xc0 [uio] ? __vfs_write+0x37/0x150 ? __getnstimeofday64+0x3b/0xd0 ? vfs_write+0xb2/0x1b0 ? syscall_trace_enter+0x1d0/0x2b0 ? SyS_write+0x55/0xc0 ? do_syscall_64+0x67/0x150 ? entry_SYSCALL64_slow_path+0x25/0x25 Code: 41 5d 41 5e 41 5f 5d c3 83 f8 01 0f 85 cf 01 00 00 48 8b 7d d0 e8 dd 5c 1d f3 41 0f b7 74 24 04 48 8b 7d c8 31 d2 e8 5c c7 1b f3 <48> 8b 7d d0 49 89 c7 c6 07 00 0f 1f 40 00 4d 85 ff 0f 84 82 01 RIP: tcmu_handle_completions+0x134/0x2f0 [target_core_user] RSP: ffffb8a2d8983d88 CR2: ffffffffffffffd0 And the crash also could happen in tcmu_page_fault and other places. Signed-off-by: Zhang Zhuoyu Signed-off-by: Xiubo Li --- drivers/target/target_core_user.c | 90 +++++++++++++++++++-------------------- 1 file changed, 45 insertions(+), 45 deletions(-) diff --git a/drivers/target/target_core_user.c b/drivers/target/target_core_user.c index 942d0942..0ff8541 100644 --- a/drivers/target/target_core_user.c +++ b/drivers/target/target_core_user.c @@ -1280,10 +1280,55 @@ static void tcmu_dev_call_rcu(struct rcu_head *p) kfree(udev); } +static int tcmu_check_and_free_pending_cmd(struct tcmu_cmd *cmd) +{ + if (test_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags)) { + kmem_cache_free(tcmu_cmd_cache, cmd); + return 0; + } + return -EINVAL; +} + +static void tcmu_blocks_release(struct tcmu_dev *udev) +{ + int i; + struct page *page; + + /* Try to release all block pages */ + mutex_lock(&udev->cmdr_lock); + for (i = 0; i <= udev->dbi_max; i++) { + page = radix_tree_delete(&udev->data_blocks, i); + if (page) { + __free_page(page); + atomic_dec(&global_db_count); + } + } + mutex_unlock(&udev->cmdr_lock); +} + static void tcmu_dev_kref_release(struct kref *kref) { struct tcmu_dev *udev = container_of(kref, struct tcmu_dev, kref); struct se_device *dev = &udev->se_dev; + struct tcmu_cmd *cmd; + bool all_expired = true; + int i; + + vfree(udev->mb_addr); + + /* Upper layer should drain all requests before calling this */ + spin_lock_irq(&udev->commands_lock); + idr_for_each_entry(&udev->commands, cmd, i) { + if (tcmu_check_and_free_pending_cmd(cmd) != 0) + all_expired = false; + } + idr_destroy(&udev->commands); + spin_unlock_irq(&udev->commands_lock); + WARN_ON(!all_expired); + + tcmu_blocks_release(udev); + + uio_unregister_device(&udev->uio_info); call_rcu(&dev->rcu_head, tcmu_dev_call_rcu); } @@ -1534,37 +1579,11 @@ static int tcmu_configure_device(struct se_device *dev) return ret; } -static int tcmu_check_and_free_pending_cmd(struct tcmu_cmd *cmd) -{ - if (test_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags)) { - kmem_cache_free(tcmu_cmd_cache, cmd); - return 0; - } - return -EINVAL; -} - static bool tcmu_dev_configured(struct tcmu_dev *udev) { return udev->uio_info.uio_dev ? true : false; } -static void tcmu_blocks_release(struct tcmu_dev *udev) -{ - int i; - struct page *page; - - /* Try to release all block pages */ - mutex_lock(&udev->cmdr_lock); - for (i = 0; i <= udev->dbi_max; i++) { - page = radix_tree_delete(&udev->data_blocks, i); - if (page) { - __free_page(page); - atomic_dec(&global_db_count); - } - } - mutex_unlock(&udev->cmdr_lock); -} - static void tcmu_free_device(struct se_device *dev) { struct tcmu_dev *udev = TCMU_DEV(dev); @@ -1576,9 +1595,6 @@ static void tcmu_free_device(struct se_device *dev) static void tcmu_destroy_device(struct se_device *dev) { struct tcmu_dev *udev = TCMU_DEV(dev); - struct tcmu_cmd *cmd; - bool all_expired = true; - int i; del_timer_sync(&udev->timeout); @@ -1586,24 +1602,8 @@ static void tcmu_destroy_device(struct se_device *dev) list_del(&udev->node); mutex_unlock(&root_udev_mutex); - vfree(udev->mb_addr); - - /* Upper layer should drain all requests before calling this */ - spin_lock_irq(&udev->commands_lock); - idr_for_each_entry(&udev->commands, cmd, i) { - if (tcmu_check_and_free_pending_cmd(cmd) != 0) - all_expired = false; - } - idr_destroy(&udev->commands); - spin_unlock_irq(&udev->commands_lock); - WARN_ON(!all_expired); - - tcmu_blocks_release(udev); - tcmu_netlink_event(udev, TCMU_CMD_REMOVED_DEVICE, 0, NULL); - uio_unregister_device(&udev->uio_info); - /* release ref from configure */ kref_put(&udev->kref, tcmu_dev_kref_release); }