From patchwork Tue Oct 15 13:05:56 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yufen Yu X-Patchwork-Id: 11190307 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 29665112B for ; Tue, 15 Oct 2019 12:44:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1284C21925 for ; Tue, 15 Oct 2019 12:44:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728731AbfJOMo0 (ORCPT ); Tue, 15 Oct 2019 08:44:26 -0400 Received: from szxga05-in.huawei.com ([45.249.212.191]:3765 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726721AbfJOMo0 (ORCPT ); Tue, 15 Oct 2019 08:44:26 -0400 Received: from DGGEMS414-HUB.china.huawei.com (unknown [172.30.72.58]) by Forcepoint Email with ESMTP id 3F622109782877069354; Tue, 15 Oct 2019 20:44:23 +0800 (CST) Received: from huawei.com (10.175.124.28) by DGGEMS414-HUB.china.huawei.com (10.3.19.214) with Microsoft SMTP Server id 14.3.439.0; Tue, 15 Oct 2019 20:44:20 +0800 From: Yufen Yu To: , CC: Subject: [PATCH] scsi: core: try to get module before removing devcie Date: Tue, 15 Oct 2019 21:05:56 +0800 Message-ID: <20191015130556.18061-1-yuyufen@huawei.com> X-Mailer: git-send-email 2.17.2 MIME-Version: 1.0 X-Originating-IP: [10.175.124.28] X-CFilter-Loop: Reflected Sender: linux-scsi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org We have a test case like block/001 in blktests, which will create a scsi device by loading scsi_debug module and then try to delete the device by sysfs interface. At the same time, it may remove the scsi_debug module. And getting a invalid paging request BUG_ON as following: [ 34.625854] BUG: unable to handle page fault for address: ffffffffa0016bb8 [ 34.629189] Oops: 0000 [#1] SMP PTI [ 34.629618] CPU: 1 PID: 450 Comm: bash Tainted: G W 5.4.0-rc3+ #473 [ 34.632524] RIP: 0010:scsi_proc_hostdir_rm+0x5/0xa0 [ 34.643555] CR2: ffffffffa0016bb8 CR3: 000000012cd88000 CR4: 00000000000006e0 [ 34.644545] Call Trace: [ 34.644907] scsi_host_dev_release+0x6b/0x1f0 [ 34.645511] device_release+0x74/0x110 [ 34.646046] kobject_put+0x116/0x390 [ 34.646559] put_device+0x17/0x30 [ 34.647041] scsi_target_dev_release+0x2b/0x40 [ 34.647652] device_release+0x74/0x110 [ 34.648186] kobject_put+0x116/0x390 [ 34.648691] put_device+0x17/0x30 [ 34.649157] scsi_device_dev_release_usercontext+0x2e8/0x360 [ 34.649953] execute_in_process_context+0x29/0x80 [ 34.650603] scsi_device_dev_release+0x20/0x30 [ 34.651221] device_release+0x74/0x110 [ 34.651732] kobject_put+0x116/0x390 [ 34.652230] sysfs_unbreak_active_protection+0x3f/0x50 [ 34.652935] sdev_store_delete.cold.4+0x71/0x8f [ 34.653579] dev_attr_store+0x1b/0x40 [ 34.654103] sysfs_kf_write+0x3d/0x60 [ 34.654603] kernfs_fop_write+0x174/0x250 [ 34.655165] __vfs_write+0x1f/0x60 [ 34.655639] vfs_write+0xc7/0x280 [ 34.656117] ksys_write+0x6d/0x140 [ 34.656591] __x64_sys_write+0x1e/0x30 [ 34.657114] do_syscall_64+0xb1/0x400 [ 34.657627] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 34.658335] RIP: 0033:0x7f156f337130 During deleting scsi target, the scsi_debug module have been removed. Then, sdebug_driver_template belonged to the module cannot be accessd, resulting in scsi_proc_hostdir_rm() BUG_ON. To fix the bug, we add scsi_device_get() in sdev_store_delete() to try to increase refcount of module, avoiding the module been removed. Cc: stable@vger.kernel.org Signed-off-by: Yufen Yu Reviewed-by: Bart Van Assche --- drivers/scsi/scsi_sysfs.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c index 64c96c7828ee..6d7362e7367e 100644 --- a/drivers/scsi/scsi_sysfs.c +++ b/drivers/scsi/scsi_sysfs.c @@ -730,6 +730,14 @@ sdev_store_delete(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) { struct kernfs_node *kn; + struct scsi_device *sdev = to_scsi_device(dev); + + /* + * We need to try to get module, avoiding the module been removed + * during delete. + */ + if (scsi_device_get(sdev)) + return -ENODEV; kn = sysfs_break_active_protection(&dev->kobj, &attr->attr); WARN_ON_ONCE(!kn); @@ -744,9 +752,10 @@ sdev_store_delete(struct device *dev, struct device_attribute *attr, * state into SDEV_DEL. */ device_remove_file(dev, attr); - scsi_remove_device(to_scsi_device(dev)); + scsi_remove_device(sdev); if (kn) sysfs_unbreak_active_protection(kn); + scsi_device_put(sdev); return count; }; static DEVICE_ATTR(delete, S_IWUSR, NULL, sdev_store_delete);