From patchwork Fri Feb 5 06:56:49 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sun Ke X-Patchwork-Id: 12069387 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=-16.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham 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 49E35C433E0 for ; Fri, 5 Feb 2021 06:56:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1D3F064F3F for ; Fri, 5 Feb 2021 06:56:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231251AbhBEG4e (ORCPT ); Fri, 5 Feb 2021 01:56:34 -0500 Received: from szxga07-in.huawei.com ([45.249.212.35]:12836 "EHLO szxga07-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230413AbhBEG4e (ORCPT ); Fri, 5 Feb 2021 01:56:34 -0500 Received: from DGGEMS406-HUB.china.huawei.com (unknown [172.30.72.58]) by szxga07-in.huawei.com (SkyGuard) with ESMTP id 4DX5kZ48kZz7h3Z; Fri, 5 Feb 2021 14:54:30 +0800 (CST) Received: from huawei.com (10.175.101.6) by DGGEMS406-HUB.china.huawei.com (10.3.19.206) with Microsoft SMTP Server id 14.3.498.0; Fri, 5 Feb 2021 14:55:41 +0800 From: Sun Ke To: , , CC: , , , Subject: [PATCH v5 1/2] nbd: Fix NULL pointer in flush_workqueue Date: Fri, 5 Feb 2021 01:56:49 -0500 Message-ID: <20210205065650.2357457-2-sunke32@huawei.com> X-Mailer: git-send-email 2.25.4 In-Reply-To: <20210205065650.2357457-1-sunke32@huawei.com> References: <20210205065650.2357457-1-sunke32@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.175.101.6] X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org Open /dev/nbdX first, the config_refs will be 1 and the pointers in nbd_device are still null. Disconnect /dev/nbdX, then reference a null recv_workq. The protection by config_refs in nbd_genl_disconnect is useless. [ 656.366194] BUG: kernel NULL pointer dereference, address: 0000000000000020 [ 656.368943] #PF: supervisor write access in kernel mode [ 656.369844] #PF: error_code(0x0002) - not-present page [ 656.370717] PGD 10cc87067 P4D 10cc87067 PUD 1074b4067 PMD 0 [ 656.371693] Oops: 0002 [#1] SMP [ 656.372242] CPU: 5 PID: 7977 Comm: nbd-client Not tainted 5.11.0-rc5-00040-g76c057c84d28 #1 [ 656.373661] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS ?-20190727_073836-buildvm-ppc64le-16.ppc.fedoraproject.org-3.fc31 04/01/2014 [ 656.375904] RIP: 0010:mutex_lock+0x29/0x60 [ 656.376627] Code: 00 0f 1f 44 00 00 55 48 89 fd 48 83 05 6f d7 fe 08 01 e8 7a c3 ff ff 48 83 05 6a d7 fe 08 01 31 c0 65 48 8b 14 25 00 6d 01 00 48 0f b1 55 d [ 656.378934] RSP: 0018:ffffc900005eb9b0 EFLAGS: 00010246 [ 656.379350] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 [ 656.379915] RDX: ffff888104cf2600 RSI: ffffffffaae8f452 RDI: 0000000000000020 [ 656.380473] RBP: 0000000000000020 R08: 0000000000000000 R09: ffff88813bd6b318 [ 656.381039] R10: 00000000000000c7 R11: fefefefefefefeff R12: ffff888102710b40 [ 656.381599] R13: ffffc900005eb9e0 R14: ffffffffb2930680 R15: ffff88810770ef00 [ 656.382166] FS: 00007fdf117ebb40(0000) GS:ffff88813bd40000(0000) knlGS:0000000000000000 [ 656.382806] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 656.383261] CR2: 0000000000000020 CR3: 0000000100c84000 CR4: 00000000000006e0 [ 656.383819] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 656.384370] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 656.384927] Call Trace: [ 656.385111] flush_workqueue+0x92/0x6c0 [ 656.385395] nbd_disconnect_and_put+0x81/0xd0 [ 656.385716] nbd_genl_disconnect+0x125/0x2a0 [ 656.386034] genl_family_rcv_msg_doit.isra.0+0x102/0x1b0 [ 656.386422] genl_rcv_msg+0xfc/0x2b0 [ 656.386685] ? nbd_ioctl+0x490/0x490 [ 656.386954] ? genl_family_rcv_msg_doit.isra.0+0x1b0/0x1b0 [ 656.387354] netlink_rcv_skb+0x62/0x180 [ 656.387638] genl_rcv+0x34/0x60 [ 656.387874] netlink_unicast+0x26d/0x590 [ 656.388162] netlink_sendmsg+0x398/0x6c0 [ 656.388451] ? netlink_rcv_skb+0x180/0x180 [ 656.388750] ____sys_sendmsg+0x1da/0x320 [ 656.389038] ? ____sys_recvmsg+0x130/0x220 [ 656.389334] ___sys_sendmsg+0x8e/0xf0 [ 656.389605] ? ___sys_recvmsg+0xa2/0xf0 [ 656.389889] ? handle_mm_fault+0x1671/0x21d0 [ 656.390201] __sys_sendmsg+0x6d/0xe0 [ 656.390464] __x64_sys_sendmsg+0x23/0x30 [ 656.390751] do_syscall_64+0x45/0x70 [ 656.391017] entry_SYSCALL_64_after_hwframe+0x44/0xa9 Fixes: e9e006f5fcf2 ("nbd: fix max number of supported devs") Suggested-by: Markus Elfring Signed-off-by: Sun Ke --- v4: Share exception handling code for if branches v3: Do not use unlock and add put_nbd. v2: Use jump target unlock. --- drivers/block/nbd.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c index e6ea5d344f87..3c9b3bf3f4c2 100644 --- a/drivers/block/nbd.c +++ b/drivers/block/nbd.c @@ -2014,17 +2014,20 @@ static int nbd_genl_disconnect(struct sk_buff *skb, struct genl_info *info) mutex_lock(&nbd_index_mutex); nbd = idr_find(&nbd_index_idr, index); if (!nbd) { - mutex_unlock(&nbd_index_mutex); printk(KERN_ERR "nbd: couldn't find device at index %d\n", index); - return -EINVAL; + goto unlock_index; } - if (!refcount_inc_not_zero(&nbd->refs)) { - mutex_unlock(&nbd_index_mutex); + mutex_lock(&nbd->config_lock); + if (!refcount_inc_not_zero(&nbd->refs) || !nbd->recv_workq) { + mutex_unlock(&nbd->config_lock); printk(KERN_ERR "nbd: device at index %d is going down\n", index); +unlock_index: + mutex_unlock(&nbd_index_mutex); return -EINVAL; } + mutex_unlock(&nbd->config_lock); mutex_unlock(&nbd_index_mutex); if (!refcount_inc_not_zero(&nbd->config_refs)) { nbd_put(nbd); From patchwork Fri Feb 5 06:56:50 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Sun Ke X-Patchwork-Id: 12069385 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=-16.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham 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 E6639C433E6 for ; Fri, 5 Feb 2021 06:56:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B5F3464F3B for ; Fri, 5 Feb 2021 06:56:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231239AbhBEG4e (ORCPT ); Fri, 5 Feb 2021 01:56:34 -0500 Received: from szxga07-in.huawei.com ([45.249.212.35]:12837 "EHLO szxga07-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231200AbhBEG4e (ORCPT ); Fri, 5 Feb 2021 01:56:34 -0500 Received: from DGGEMS406-HUB.china.huawei.com (unknown [172.30.72.58]) by szxga07-in.huawei.com (SkyGuard) with ESMTP id 4DX5kZ4RKxz7hSq; Fri, 5 Feb 2021 14:54:30 +0800 (CST) Received: from huawei.com (10.175.101.6) by DGGEMS406-HUB.china.huawei.com (10.3.19.206) with Microsoft SMTP Server id 14.3.498.0; Fri, 5 Feb 2021 14:55:41 +0800 From: Sun Ke To: , , CC: , , , Subject: [PATCH v5 2/2] nbd: share nbd_put and return by goto put_nbd Date: Fri, 5 Feb 2021 01:56:50 -0500 Message-ID: <20210205065650.2357457-3-sunke32@huawei.com> X-Mailer: git-send-email 2.25.4 In-Reply-To: <20210205065650.2357457-1-sunke32@huawei.com> References: <20210205065650.2357457-1-sunke32@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.175.101.6] X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org Replace the following two statements by the statement “goto put_nbd;” nbd_put(nbd); return 0; Suggested-by: Markus Elfring Signed-off-by: Sun Ke --- drivers/block/nbd.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c index 3c9b3bf3f4c2..ecae81e43122 100644 --- a/drivers/block/nbd.c +++ b/drivers/block/nbd.c @@ -2029,12 +2029,11 @@ static int nbd_genl_disconnect(struct sk_buff *skb, struct genl_info *info) } mutex_unlock(&nbd->config_lock); mutex_unlock(&nbd_index_mutex); - if (!refcount_inc_not_zero(&nbd->config_refs)) { - nbd_put(nbd); - return 0; - } + if (!refcount_inc_not_zero(&nbd->config_refs)) + goto put_nbd; nbd_disconnect_and_put(nbd); nbd_config_put(nbd); +put_nbd: nbd_put(nbd); return 0; }