From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-1576794-1517682424-2-17907379372582560185 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 0.001, RCVD_IN_DNSWL_HI -5, T_RP_MATCHES_RCVD -0.01, LANGUAGES roen, BAYES_USED global, SA_VERSION 3.4.0 X-Spam-source: IP='209.132.180.67', Host='vger.kernel.org', Country='US', FromHeader='com', MailFrom='org', XOriginatingCountry='US' X-Spam-charsets: plain='iso-8859-1' 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=1517682423; b=lj5ugjmFmz2WcmEulilQh5/y7wGCq2Qj5kSPQ4eef97iFrV FS17uQVKBdV6LN+cjROIUotg2pTgRRYRaHGRv8U5XPLk/qSuNqA6XUpXavFCcD73 Ac8NvzsAr2VI5u9ZUPtHoXEwK94XJcWynQTfeaBZrB4Ro4AHMPutP2oH6qbEeaWB lWCogY4W5lbdcLH+W6H5mBjjn+Q1yrALJ8MyfKcu0KYNgDGDeuo1PgneBQNRMczS nQUyurIXJW8K8CayKea84KcEAjufK2tYmERsXVI2BDfA3AOaRh1Z+tjuKh9Ng6fx scF0X02RQBH+5EoXLQrt1WX6VNDGuoIMpKpdUVw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=from:to:cc:subject:date:message-id :references:in-reply-to:content-type:content-transfer-encoding :mime-version:sender:list-id; s=arctest; t=1517682423; bh=DEixaS hNQsK0EYK+AwOWZW7hFpnqwXAS4mYYC/1kFEE=; b=Jb1GgJWBOrGtdn7vuww09G DTOiAxmALuekT5PiANqwSYBdD4kChb5bECofiho8DFV0XuTOLsckpttq4Z+hRSep 6SxzyN52P3hhDB7/FWaNW92NlhR52CtPzh6Cdsmjl/h40Q61Wx413jvgIWY0RLFO 1a4lkwxcxjCeHQRbV7JErdhXOLoV/vtpfynZScltpQPDWsjESHA4bBx5fd/YZioE nfHZF3YkXIEumxF8NkcwVPLJ3d7ev06z/o03M+Lz7+83VSljodMS385j0ldyTuCV J1NfNxZmVZOqTjVTuiIBPynoycQc5qkQai6Fgy5CsSCSKUUtGhy2+6hEKlePudIQ == ARC-Authentication-Results: i=1; mx4.messagingengine.com; arc=none (no signatures found); dkim=pass (1024-bit rsa key sha256) header.d=microsoft.com header.i=@microsoft.com header.b=TSO0Z8+L x-bits=1024 x-keytype=rsa x-algorithm=sha256 x-selector=selector1; dmarc=pass (p=reject,has-list-id=yes,d=none) header.from=microsoft.com; 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=microsoft.com header.result=pass header_is_org_domain=yes Authentication-Results: mx4.messagingengine.com; arc=none (no signatures found); dkim=pass (1024-bit rsa key sha256) header.d=microsoft.com header.i=@microsoft.com header.b=TSO0Z8+L x-bits=1024 x-keytype=rsa x-algorithm=sha256 x-selector=selector1; dmarc=pass (p=reject,has-list-id=yes,d=none) header.from=microsoft.com; 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=microsoft.com header.result=pass header_is_org_domain=yes Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754432AbeBCSXw (ORCPT ); Sat, 3 Feb 2018 13:23:52 -0500 Received: from mail-by2nam03on0126.outbound.protection.outlook.com ([104.47.42.126]:45078 "EHLO NAM03-BY2-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753442AbeBCSGU (ORCPT ); Sat, 3 Feb 2018 13:06:20 -0500 From: Sasha Levin To: "linux-kernel@vger.kernel.org" , "stable@vger.kernel.org" CC: Tetsuo Handa , Aliaksei Karaliou , Glauber Costa , Al Viro , Sasha Levin Subject: [PATCH AUTOSEL for 4.4 04/32] mm,vmscan: Make unregister_shrinker() no-op if register_shrinker() failed. Thread-Topic: [PATCH AUTOSEL for 4.4 04/32] mm,vmscan: Make unregister_shrinker() no-op if register_shrinker() failed. Thread-Index: AQHTnRltwra0KYva6ECyzM4bBht5xw== Date: Sat, 3 Feb 2018 18:04:26 +0000 Message-ID: <20180203180413.7438-4-alexander.levin@microsoft.com> References: <20180203180413.7438-1-alexander.levin@microsoft.com> In-Reply-To: <20180203180413.7438-1-alexander.levin@microsoft.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [52.168.54.252] x-ms-publictraffictype: Email x-microsoft-exchange-diagnostics: 1;BL0PR2101MB1089;6:zC6XOY9kIcrcZGby/OYaDm4GmgQsVRH22XechcU4hK+QGQIaCrI2bM/CwdpfXH4ReGoku4c4M+mmCRuGG8YdWHR7MO4oLG5W551UP7n6xml71tb4XycuE5nx2nFEd7Zv+nHPRXl+xSstP1ipWlopGKDyeN4MwxzfK/RHN+UwCNGbNS6a71r2EGBXeThaUNyE8HZqkiidVTg/419qSHsdvVnkHDgRmcLVYx08Ii3f/oY30YKZV+wKd25AeSqxiZP/T2k+RS+jhmOoc8yj1CFcvXyefuIp7pzdwQHlx9OpJawJ4AkkDoFlDafoAV6C9i1mZ+JD1ekAaQCyBArvXZlrTYWxFe1I0GKztIzXPYYfo3LHpPKqa1QOsuHqNIzkGD9H;5:q/+mdNHQyR/Fy43+iZxd6CRP+tENgoFgeyvkDH6d8wBqnQlE3UmrgQknSOSy9/ATYQ1iRwFFHVCQYqbjgagpP4PxtqGN58b69qfrRBLRsLrDFXh/2RM9ikb0u10A1W9teayRiBykuN3sLsJ0Hr7W65gd899EtrrJgY8KZTd4rDA=;24:BPghZ+CZzQwqyg5vltARQ2LbrtZYnxN4v6+/EJMPSVYDc2p+VaCnXphkGfBPN84ruYI9a79tioa8JskvCc5zXDdTbv9xawunnpZME/kHSrc=;7:0JMOmzjYJUnQGWw8OVPZF1wF8HSc37CK6l2Zh6sFoWUbNwA2Xt3RPZBhrT23yJ43NME5lLXFTSS2R5j9EE+mphA2/Se0jcr+9hLjjv5nC+nkNQmamLOfdx1hbYSOVcrTBL6j8Zu9OYIwOIvkM685A5ohseJtNGrUMKm51qhfmTOP4EmYgyXgatL8HSevg5sWLLmWeUEp7eoLCHOeuYpRg+Rwyp+895v5iW1D2V1wsoeq6I3hgA6nUgtKgXi7cOuv x-ms-office365-filtering-ht: Tenant x-ms-office365-filtering-correlation-id: 0e651a39-42b4-48d5-6ce4-08d56b30a5e9 x-microsoft-antispam: UriScan:;BCL:0;PCL:0;RULEID:(7020095)(4652020)(48565401081)(4534165)(4627221)(201703031133081)(201702281549075)(5600026)(4604075)(3008032)(2017052603307)(7193020);SRVR:BL0PR2101MB1089; x-ms-traffictypediagnostic: BL0PR2101MB1089: x-microsoft-antispam-prvs: x-exchange-antispam-report-test: UriScan:(28532068793085)(215639381216008)(274141268393343)(89211679590171)(85827821059158); x-exchange-antispam-report-cfa-test: BCL:0;PCL:0;RULEID:(61425038)(6040501)(2401047)(5005006)(8121501046)(3002001)(10201501046)(3231101)(2400082)(944501161)(93006095)(93001095)(6055026)(61426038)(61427038)(6041288)(20161123562045)(20161123560045)(20161123558120)(20161123564045)(201703131423095)(201702281528075)(20161123555045)(201703061421075)(201703061406153)(6072148)(201708071742011);SRVR:BL0PR2101MB1089;BCL:0;PCL:0;RULEID:;SRVR:BL0PR2101MB1089; x-forefront-prvs: 05724A8921 x-forefront-antispam-report: SFV:NSPM;SFS:(10019020)(39380400002)(396003)(39860400002)(376002)(366004)(346002)(199004)(189003)(86362001)(575784001)(106356001)(22452003)(4326008)(97736004)(25786009)(6666003)(2950100002)(5660300001)(2906002)(81156014)(105586002)(3280700002)(8676002)(8936002)(6116002)(68736007)(81166006)(3660700001)(86612001)(2900100001)(39060400002)(107886003)(3846002)(1076002)(102836004)(26005)(6346003)(66066001)(10090500001)(76176011)(6506007)(10290500003)(186003)(6486002)(14454004)(59450400001)(6436002)(53936002)(72206003)(316002)(305945005)(7736002)(99286004)(54906003)(110136005)(36756003)(2501003)(5250100002)(6512007)(478600001)(22906009)(142933001)(217873001);DIR:OUT;SFP:1102;SCL:1;SRVR:BL0PR2101MB1089;H:BL0PR2101MB1027.namprd21.prod.outlook.com;FPR:;SPF:None;PTR:InfoNoRecords;A:1;MX:1;LANG:en; authentication-results: spf=none (sender IP is ) smtp.mailfrom=Alexander.Levin@microsoft.com; x-microsoft-antispam-message-info: 1+wCWk4dapzG/+Y7SN4w+r04SB4pKcfX9CKnPH6+ErOET/4e3XM2zJYF7ftk4vf3G7PxbCN6X2CJHKZVXb/hCQ== spamdiagnosticoutput: 1:99 spamdiagnosticmetadata: NSPM Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-OriginatorOrg: microsoft.com X-MS-Exchange-CrossTenant-Network-Message-Id: 0e651a39-42b4-48d5-6ce4-08d56b30a5e9 X-MS-Exchange-CrossTenant-originalarrivaltime: 03 Feb 2018 18:04:26.0183 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: 72f988bf-86f1-41af-91ab-2d7cd011db47 X-MS-Exchange-Transport-CrossTenantHeadersStamped: BL0PR2101MB1089 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: From: Tetsuo Handa [ Upstream commit bb422a738f6566f7439cd347d54e321e4fe92a9f ] Syzbot caught an oops at unregister_shrinker() because combination of commit 1d3d4437eae1bb29 ("vmscan: per-node deferred work") and fault injection made register_shrinker() fail and the caller of register_shrinker() did not check for failure. ---------- [ 554.881422] FAULT_INJECTION: forcing a failure. [ 554.881422] name failslab, interval 1, probability 0, space 0, times 0 [ 554.881438] CPU: 1 PID: 13231 Comm: syz-executor1 Not tainted 4.14.0-rc8= + #82 [ 554.881443] Hardware name: Google Google Compute Engine/Google Compute E= ngine, BIOS Google 01/01/2011 [ 554.881445] Call Trace: [ 554.881459] dump_stack+0x194/0x257 [ 554.881474] ? arch_local_irq_restore+0x53/0x53 [ 554.881486] ? find_held_lock+0x35/0x1d0 [ 554.881507] should_fail+0x8c0/0xa40 [ 554.881522] ? fault_create_debugfs_attr+0x1f0/0x1f0 [ 554.881537] ? check_noncircular+0x20/0x20 [ 554.881546] ? find_next_zero_bit+0x2c/0x40 [ 554.881560] ? ida_get_new_above+0x421/0x9d0 [ 554.881577] ? find_held_lock+0x35/0x1d0 [ 554.881594] ? __lock_is_held+0xb6/0x140 [ 554.881628] ? check_same_owner+0x320/0x320 [ 554.881634] ? lock_downgrade+0x990/0x990 [ 554.881649] ? find_held_lock+0x35/0x1d0 [ 554.881672] should_failslab+0xec/0x120 [ 554.881684] __kmalloc+0x63/0x760 [ 554.881692] ? lock_downgrade+0x990/0x990 [ 554.881712] ? register_shrinker+0x10e/0x2d0 [ 554.881721] ? trace_event_raw_event_module_request+0x320/0x320 [ 554.881737] register_shrinker+0x10e/0x2d0 [ 554.881747] ? prepare_kswapd_sleep+0x1f0/0x1f0 [ 554.881755] ? _down_write_nest_lock+0x120/0x120 [ 554.881765] ? memcpy+0x45/0x50 [ 554.881785] sget_userns+0xbcd/0xe20 (...snipped...) [ 554.898693] kasan: CONFIG_KASAN_INLINE enabled [ 554.898724] kasan: GPF could be caused by NULL-ptr deref or user memory = access [ 554.898732] general protection fault: 0000 [#1] SMP KASAN [ 554.898737] Dumping ftrace buffer: [ 554.898741] (ftrace buffer empty) [ 554.898743] Modules linked in: [ 554.898752] CPU: 1 PID: 13231 Comm: syz-executor1 Not tainted 4.14.0-rc8= + #82 [ 554.898755] Hardware name: Google Google Compute Engine/Google Compute E= ngine, BIOS Google 01/01/2011 [ 554.898760] task: ffff8801d1dbe5c0 task.stack: ffff8801c9e38000 [ 554.898772] RIP: 0010:__list_del_entry_valid+0x7e/0x150 [ 554.898775] RSP: 0018:ffff8801c9e3f108 EFLAGS: 00010246 [ 554.898780] RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 00000000000= 00000 [ 554.898784] RDX: 0000000000000000 RSI: ffff8801c53c6f98 RDI: ffff8801c53= c6fa0 [ 554.898788] RBP: ffff8801c9e3f120 R08: 1ffff100393c7d55 R09: 00000000000= 00004 [ 554.898791] R10: ffff8801c9e3ef70 R11: 0000000000000000 R12: 00000000000= 00000 [ 554.898795] R13: dffffc0000000000 R14: 1ffff100393c7e45 R15: ffff8801c53= c6f98 [ 554.898800] FS: 0000000000000000(0000) GS:ffff8801db300000(0000) knlGS:= 0000000000000000 [ 554.898804] CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033 [ 554.898807] CR2: 00000000dbc23000 CR3: 00000001c7269000 CR4: 00000000001= 406e0 [ 554.898813] DR0: 0000000020000000 DR1: 0000000020000000 DR2: 00000000000= 00000 [ 554.898816] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 00000000000= 00600 [ 554.898818] Call Trace: [ 554.898828] unregister_shrinker+0x79/0x300 [ 554.898837] ? perf_trace_mm_vmscan_writepage+0x750/0x750 [ 554.898844] ? down_write+0x87/0x120 [ 554.898851] ? deactivate_super+0x139/0x1b0 [ 554.898857] ? down_read+0x150/0x150 [ 554.898864] ? check_same_owner+0x320/0x320 [ 554.898875] deactivate_locked_super+0x64/0xd0 [ 554.898883] deactivate_super+0x141/0x1b0 ---------- Since allowing register_shrinker() callers to call unregister_shrinker() when register_shrinker() failed can simplify error recovery path, this patch makes unregister_shrinker() no-op when register_shrinker() failed. Also, reset shrinker->nr_deferred in case unregister_shrinker() was by error called twice. Signed-off-by: Tetsuo Handa Signed-off-by: Aliaksei Karaliou Reported-by: syzbot Cc: Glauber Costa Cc: Al Viro Signed-off-by: Al Viro Signed-off-by: Sasha Levin --- mm/vmscan.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/mm/vmscan.c b/mm/vmscan.c index 440c2df9be82..930f7c67a9c1 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -254,10 +254,13 @@ EXPORT_SYMBOL(register_shrinker); */ void unregister_shrinker(struct shrinker *shrinker) { + if (!shrinker->nr_deferred) + return; down_write(&shrinker_rwsem); list_del(&shrinker->list); up_write(&shrinker_rwsem); kfree(shrinker->nr_deferred); + shrinker->nr_deferred =3D NULL; } EXPORT_SYMBOL(unregister_shrinker); =20 --=20 2.11.0