From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-564561-1519836641-2-381536713044482250 X-Sieve: CMU Sieve 3.0 X-Spam-known-sender: no X-Spam-score: 0.0 X-Spam-hits: BAYES_00 -1.9, HEADER_FROM_DIFFERENT_DOMAINS 0.249, ME_NOAUTH 0.01, RCVD_IN_DNSWL_HI -5, T_RP_MATCHES_RCVD -0.01, LANGUAGES en, BAYES_USED global, SA_VERSION 3.4.0 X-Spam-source: IP='209.132.180.67', Host='vger.kernel.org', Country='CN', FromHeader='uk', MailFrom='org' X-Spam-charsets: plain='UTF-8' X-Resolved-to: greg@kroah.com X-Delivered-to: greg@kroah.com X-Mail-from: stable-owner@vger.kernel.org ARC-Seal: i=1; a=rsa-sha256; cv=none; d=messagingengine.com; s=arctest; t=1519836640; b=qu8h/u0n3grrFTa2+Y52iraoHE6nzWFfn9f1yPfot+353Jo GD9kSL+v7R8WD77dRg8AthWgZATKQ91ppqUqbj6Y4dgk1Sv4+HxSGlA3JPJTcPfZ Gsymxs4cAng+lkHk3fvZ4G3UTCVI6H0/gZtpOyoZqVmJ9XRfa4hunV1FXCcjp+Fn jZWm7vt+nkHJhM5Kfw/cPpQn3/ZC9ysxrI4br0/Gra+zKiqgDaziUZPUaLx+07sc PlAcovQz34oql3UPhP5LwsPgydxTx/dVLTrsMAI0sRkzdROjjWC8xmNoqtW03P8+ jaIXuY86pPOs2EOJ882WCcUQTJ25Gy4XzqZiZkw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=content-type:content-transfer-encoding :mime-version:from:to:cc:date:message-id:subject:in-reply-to :sender:list-id; s=arctest; t=1519836640; bh=5b8RlMT5qbfga2910LG 4czP84WEW3Czm51sXzD/MwWk=; b=AFBu6thJbLksTO9X3p5kE/1r29JGHMz8UpD CB2KfBB4uLyQKuOswJqW8SO5w2RgW9pflWAaVEPbV4qMF3FeVZv6ZyGD4qIfsA5M lVdulDOfPM3FStfa2z+Fvz5qye3Ov1WK9v2EKsh4UIKaEiHKgVxf6s/JCgwH1hop 1gLpCvB+66YbTasecbmouX5KQldBZTXBa05hQmjNspeY9hCINLiI2hBdHBs31UcA dopqpKzaS6pdms4Q324gJ8Y24lzIDHF6ogFzqMz4uEwmnWT8d7++ovJP+3lk8Y7k 2EqEoyHB2cDxmejoR+wmLEsluBkUhCo4wyvpByWgWwFXKkI1wsQ== ARC-Authentication-Results: i=1; mx1.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=decadent.org.uk; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=decadent.org.uk header.result=pass header_is_org_domain=yes Authentication-Results: mx1.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=decadent.org.uk; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=decadent.org.uk header.result=pass header_is_org_domain=yes Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933993AbeB1P6d (ORCPT ); Wed, 28 Feb 2018 10:58:33 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:34563 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934242AbeB1P63 (ORCPT ); Wed, 28 Feb 2018 10:58:29 -0500 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Mike Snitzer" , "monty_pavel@sina.com" Date: Wed, 28 Feb 2018 15:20:18 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 054/254] dm: fix various targets to dm_register_target after module __init resources created In-Reply-To: X-SA-Exim-Connect-IP: 2a02:8011:400e:2:6f00:88c8:c921:d332 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: stable-owner@vger.kernel.org X-Mailing-List: stable@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 3.16.55-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: "monty_pavel@sina.com" commit 7e6358d244e4706fe612a77b9c36519a33600ac0 upstream. A NULL pointer is seen if two concurrent "vgchange -ay -K " processes race to load the dm-thin-pool module: PID: 25992 TASK: ffff883cd7d23500 CPU: 4 COMMAND: "vgchange" #0 [ffff883cd743d600] machine_kexec at ffffffff81038fa9 0000001 [ffff883cd743d660] crash_kexec at ffffffff810c5992 0000002 [ffff883cd743d730] oops_end at ffffffff81515c90 0000003 [ffff883cd743d760] no_context at ffffffff81049f1b 0000004 [ffff883cd743d7b0] __bad_area_nosemaphore at ffffffff8104a1a5 0000005 [ffff883cd743d800] bad_area at ffffffff8104a2ce 0000006 [ffff883cd743d830] __do_page_fault at ffffffff8104aa6f 0000007 [ffff883cd743d950] do_page_fault at ffffffff81517bae 0000008 [ffff883cd743d980] page_fault at ffffffff81514f95 [exception RIP: kmem_cache_alloc+108] RIP: ffffffff8116ef3c RSP: ffff883cd743da38 RFLAGS: 00010046 RAX: 0000000000000004 RBX: ffffffff81121b90 RCX: ffff881bf1e78cc0 RDX: 0000000000000000 RSI: 00000000000000d0 RDI: 0000000000000000 RBP: ffff883cd743da68 R8: ffff881bf1a4eb00 R9: 0000000080042000 R10: 0000000000002000 R11: 0000000000000000 R12: 00000000000000d0 R13: 0000000000000000 R14: 00000000000000d0 R15: 0000000000000246 ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018 0000009 [ffff883cd743da70] mempool_alloc_slab at ffffffff81121ba5 0000010 [ffff883cd743da80] mempool_create_node at ffffffff81122083 0000011 [ffff883cd743dad0] mempool_create at ffffffff811220f4 0000012 [ffff883cd743dae0] pool_ctr at ffffffffa08de049 [dm_thin_pool] 0000013 [ffff883cd743dbd0] dm_table_add_target at ffffffffa0005f2f [dm_mod] 0000014 [ffff883cd743dc30] table_load at ffffffffa0008ba9 [dm_mod] 0000015 [ffff883cd743dc90] ctl_ioctl at ffffffffa0009dc4 [dm_mod] The race results in a NULL pointer because: Process A (vgchange -ay -K): a. send DM_LIST_VERSIONS_CMD ioctl; b. pool_target not registered; c. modprobe dm_thin_pool and wait until end. Process B (vgchange -ay -K): a. send DM_LIST_VERSIONS_CMD ioctl; b. pool_target registered; c. table_load->dm_table_add_target->pool_ctr; d. _new_mapping_cache is NULL and panic. Note: 1. process A and process B are two concurrent processes. 2. pool_target can be detected by process B but _new_mapping_cache initialization has not ended. To fix dm-thin-pool, and other targets (cache, multipath, and snapshot) with the same problem, simply dm_register_target() after all resources created during module init (as labelled with __init) are finished. Signed-off-by: monty Signed-off-by: Mike Snitzer [bwh: Backported to 3.16: adjust context] Signed-off-by: Ben Hutchings --- drivers/md/dm-cache-target.c | 12 +++++------ drivers/md/dm-mpath.c | 18 ++++++++--------- drivers/md/dm-snap.c | 48 ++++++++++++++++++++++---------------------- drivers/md/dm-thin.c | 22 +++++++++----------- 4 files changed, 49 insertions(+), 51 deletions(-) --- a/drivers/md/dm-cache-target.c +++ b/drivers/md/dm-cache-target.c @@ -3108,18 +3108,18 @@ static int __init dm_cache_init(void) { int r; - r = dm_register_target(&cache_target); - if (r) { - DMERR("cache target registration failed: %d", r); - return r; - } - migration_cache = KMEM_CACHE(dm_cache_migration, 0); if (!migration_cache) { dm_unregister_target(&cache_target); return -ENOMEM; } + r = dm_register_target(&cache_target); + if (r) { + DMERR("cache target registration failed: %d", r); + return r; + } + return 0; } --- a/drivers/md/dm-mpath.c +++ b/drivers/md/dm-mpath.c @@ -1688,13 +1688,6 @@ static int __init dm_multipath_init(void if (!_mpio_cache) return -ENOMEM; - r = dm_register_target(&multipath_target); - if (r < 0) { - DMERR("register failed %d", r); - r = -EINVAL; - goto bad_register_target; - } - kmultipathd = alloc_workqueue("kmpathd", WQ_MEM_RECLAIM, 0); if (!kmultipathd) { DMERR("failed to create workqueue kmpathd"); @@ -1716,17 +1709,24 @@ static int __init dm_multipath_init(void goto bad_alloc_kmpath_handlerd; } + r = dm_register_target(&multipath_target); + if (r < 0) { + DMERR("register failed %d", r); + r = -EINVAL; + goto bad_register_target; + } + DMINFO("version %u.%u.%u loaded", multipath_target.version[0], multipath_target.version[1], multipath_target.version[2]); return 0; +bad_register_target: + destroy_workqueue(kmpath_handlerd); bad_alloc_kmpath_handlerd: destroy_workqueue(kmultipathd); bad_alloc_kmultipathd: - dm_unregister_target(&multipath_target); -bad_register_target: kmem_cache_destroy(_mpio_cache); return r; --- a/drivers/md/dm-snap.c +++ b/drivers/md/dm-snap.c @@ -2404,24 +2404,6 @@ static int __init dm_snapshot_init(void) return r; } - r = dm_register_target(&snapshot_target); - if (r < 0) { - DMERR("snapshot target register failed %d", r); - goto bad_register_snapshot_target; - } - - r = dm_register_target(&origin_target); - if (r < 0) { - DMERR("Origin target register failed %d", r); - goto bad_register_origin_target; - } - - r = dm_register_target(&merge_target); - if (r < 0) { - DMERR("Merge target register failed %d", r); - goto bad_register_merge_target; - } - r = init_origin_hash(); if (r) { DMERR("init_origin_hash failed."); @@ -2442,19 +2424,37 @@ static int __init dm_snapshot_init(void) goto bad_pending_cache; } + r = dm_register_target(&snapshot_target); + if (r < 0) { + DMERR("snapshot target register failed %d", r); + goto bad_register_snapshot_target; + } + + r = dm_register_target(&origin_target); + if (r < 0) { + DMERR("Origin target register failed %d", r); + goto bad_register_origin_target; + } + + r = dm_register_target(&merge_target); + if (r < 0) { + DMERR("Merge target register failed %d", r); + goto bad_register_merge_target; + } + return 0; -bad_pending_cache: - kmem_cache_destroy(exception_cache); -bad_exception_cache: - exit_origin_hash(); -bad_origin_hash: - dm_unregister_target(&merge_target); bad_register_merge_target: dm_unregister_target(&origin_target); bad_register_origin_target: dm_unregister_target(&snapshot_target); bad_register_snapshot_target: + kmem_cache_destroy(pending_cache); +bad_pending_cache: + kmem_cache_destroy(exception_cache); +bad_exception_cache: + exit_origin_hash(); +bad_origin_hash: dm_exception_store_exit(); return r; --- a/drivers/md/dm-thin.c +++ b/drivers/md/dm-thin.c @@ -3521,30 +3521,28 @@ static struct target_type thin_target = static int __init dm_thin_init(void) { - int r; + int r = -ENOMEM; pool_table_init(); + _new_mapping_cache = KMEM_CACHE(dm_thin_new_mapping, 0); + if (!_new_mapping_cache) + return r; + r = dm_register_target(&thin_target); if (r) - return r; + goto bad_new_mapping_cache; r = dm_register_target(&pool_target); if (r) - goto bad_pool_target; - - r = -ENOMEM; - - _new_mapping_cache = KMEM_CACHE(dm_thin_new_mapping, 0); - if (!_new_mapping_cache) - goto bad_new_mapping_cache; + goto bad_thin_target; return 0; -bad_new_mapping_cache: - dm_unregister_target(&pool_target); -bad_pool_target: +bad_thin_target: dm_unregister_target(&thin_target); +bad_new_mapping_cache: + kmem_cache_destroy(_new_mapping_cache); return r; }