From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from userp2130.oracle.com ([156.151.31.86]:57162 "EHLO userp2130.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750905AbeBXLmd (ORCPT ); Sat, 24 Feb 2018 06:42:33 -0500 Received: from pps.filterd (userp2130.oracle.com [127.0.0.1]) by userp2130.oracle.com (8.16.0.22/8.16.0.22) with SMTP id w1OBgX2K171038 for ; Sat, 24 Feb 2018 11:42:33 GMT Received: from aserv0022.oracle.com (aserv0022.oracle.com [141.146.126.234]) by userp2130.oracle.com with ESMTP id 2gb710g1js-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK) for ; Sat, 24 Feb 2018 11:42:33 +0000 Received: from userv0121.oracle.com (userv0121.oracle.com [156.151.31.72]) by aserv0022.oracle.com (8.14.4/8.14.4) with ESMTP id w1OBgVO9032726 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL) for ; Sat, 24 Feb 2018 11:42:31 GMT Received: from abhmp0012.oracle.com (abhmp0012.oracle.com [141.146.116.18]) by userv0121.oracle.com (8.14.4/8.13.8) with ESMTP id w1OBgVVt002454 for ; Sat, 24 Feb 2018 11:42:31 GMT From: Anand Jain To: linux-btrfs@vger.kernel.org Subject: [PATCH v2] btrfs: fix null pointer deref when target device is missing Date: Sat, 24 Feb 2018 19:43:56 +0800 Message-Id: <20180224114356.18029-1-anand.jain@oracle.com> In-Reply-To: <20180223225545.GP1469@twin.jikos.cz> References: <20180223225545.GP1469@twin.jikos.cz> Sender: linux-btrfs-owner@vger.kernel.org List-ID: The replace target device can be missing when mounted with -o degraded, but we wont allocate a missing btrfs_device to it. So check the device before access. BUG: unable to handle kernel NULL pointer dereference at 00000000000000b0 IP: btrfs_destroy_dev_replace_tgtdev+0x43/0xf0 [btrfs] Call Trace: btrfs_dev_replace_cancel+0x15f/0x180 [btrfs] btrfs_ioctl+0x2216/0x2590 [btrfs] do_vfs_ioctl+0x625/0x650 SyS_ioctl+0x4e/0x80 do_syscall_64+0x5d/0x160 entry_SYSCALL64_slow_path+0x25/0x25 Signed-off-by: Anand Jain --- v1->v2: Fix change log. Fix $subject. Old $subject btrfs: fix NPD when target device is missing fs/btrfs/dev-replace.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/btrfs/dev-replace.c b/fs/btrfs/dev-replace.c index c97969b2abbd..e279f04b3388 100644 --- a/fs/btrfs/dev-replace.c +++ b/fs/btrfs/dev-replace.c @@ -312,7 +312,7 @@ void btrfs_after_dev_replace_commit(struct btrfs_fs_info *fs_info) static char* btrfs_dev_name(struct btrfs_device *device) { - if (test_bit(BTRFS_DEV_STATE_MISSING, &device->dev_state)) + if (!device || test_bit(BTRFS_DEV_STATE_MISSING, &device->dev_state)) return ""; else return rcu_str_deref(device->name); -- 2.15.0