From mboxrd@z Thu Jan 1 00:00:00 1970 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=-7.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 A3C1EC433F5 for ; Thu, 9 Sep 2021 02:52:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 70084603E9 for ; Thu, 9 Sep 2021 02:52:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236247AbhIICyE (ORCPT ); Wed, 8 Sep 2021 22:54:04 -0400 Received: from szxga01-in.huawei.com ([45.249.212.187]:19018 "EHLO szxga01-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230075AbhIICyD (ORCPT ); Wed, 8 Sep 2021 22:54:03 -0400 Received: from dggeme766-chm.china.huawei.com (unknown [172.30.72.57]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4H4k3R0T8lzbmNx; Thu, 9 Sep 2021 10:48:51 +0800 (CST) Received: from [10.174.176.245] (10.174.176.245) by dggeme766-chm.china.huawei.com (10.3.19.112) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2308.8; Thu, 9 Sep 2021 10:52:51 +0800 Subject: Re: [PATCH v2 0/3] auth_gss: netns refcount leaks when use-gss-proxy==1 To: "J. Bruce Fields" CC: Wenbin Zeng , , , , , , , , , , , , , , , , , , References: <1556692945-3996-1-git-send-email-wenbinzeng@tencent.com> <1557470163-30071-1-git-send-email-wenbinzeng@tencent.com> <20190515010331.GA3232@fieldses.org> <20190612083755.GA27776@bridge.tencent.com> <20190612155224.GF16331@fieldses.org> <2c9e3d91-f4b3-6f6a-0dc0-21cef4fab3bb@huawei.com> <20210908205103.GE23978@fieldses.org> From: "wanghai (M)" Message-ID: Date: Thu, 9 Sep 2021 10:52:51 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: <20210908205103.GE23978@fieldses.org> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 8bit X-Originating-IP: [10.174.176.245] X-ClientProxiedBy: dggems704-chm.china.huawei.com (10.3.19.181) To dggeme766-chm.china.huawei.com (10.3.19.112) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org 在 2021/9/9 4:51, J. Bruce Fields 写道: > On Tue, Sep 07, 2021 at 10:48:52PM +0800, wanghai (M) wrote: >> 在 2019/6/12 23:52, J. Bruce Fields 写道: >>> On Wed, Jun 12, 2019 at 04:37:55PM +0800, Wenbin Zeng wrote: >>>> On Tue, May 14, 2019 at 09:03:31PM -0400, J. Bruce Fields wrote: >>>>> Whoops, I was slow to test these. I'm getting failuring krb5 nfs >>>>> mounts, and the following the server's logs. Dropping the three patches >>>>> for now. >>>> My bad, I should have found it earlier. Thank you for testing it, Bruce. >>>> >>>> I figured it out, the problem that you saw is due to the following code: >>>> the if-condition is incorrect here because sn->gssp_clnt==NULL doesn't mean >>>> inexistence of 'use-gss-proxy': >>> Thanks, but with the new patches I see the following. I haven't tried >>> to investigate. >> This patchset adds the nsfs_evict()->netns_evict() code for breaking >> deadlock bugs that exist, but this may cause double free because >> nsfs_evict()->netns_evict() may be called multiple times. >> >> for example: >> >> int main() >> { >>     int fd = open("/proc/self/ns/net", O_RDONLY); >>     close(fd); >> >>     fd = open("/proc/self/ns/net", O_RDONLY); >>     close(fd); >> } >> >> Therefore, the nsfs evict cannot be used to break the deadlock. > Sorry, I haven't really been following this, but I though this problem > was fixed by your checking for gssp_clnt (instead of just relying on the > use_gssp_proc check) in v3 of your patches? > > --b. Sorry, I'm not Wenbin Zeng. I recently encountered the same problem and found that Zeng had posted a patchset for it. However, after my own analysis, I found that Zeng's patchset will cause the dobule free problem. The v3 patches also has the double free issue. Because nsfs_evict()->netns_evict()->gss_svc_shutdown_net()->cache_purge() can be called multiple times. And, even if there is no double free problem, the application can make the evict called earlier by 'open("/proc/self/ns/net", O_RDONLY); close(fd);', which makes sunrpc unusable. Therefore, the v3 patchset is also not applicable. This issue causes an OOM on my server after multiple docker creation and destruction, and I don't have a good solution at the moment. >> A large number of netns leaks may cause OOM problems, currently I >> can't find a good solution to fix it, does anyone have a good idea? >>> --b. >>> >>> [ 2908.134813] ------------[ cut here ]------------ >>> [ 2908.135732] name 'use-gss-proxy' >>> [ 2908.136276] WARNING: CPU: 2 PID: 15032 at fs/proc/generic.c:673 remove_proc_entry+0x124/0x190 >>> [ 2908.138144] Modules linked in: nfsv4 rpcsec_gss_krb5 nfsv3 nfs_acl nfs lockd grace auth_rpcgss sunrpc >>> [ 2908.140183] CPU: 2 PID: 15032 Comm: (coredump) Not tainted 5.2.0-rc2-00441-gaef575f54640 #2257 >>> [ 2908.142062] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-2.fc30 04/01/2014 >>> [ 2908.143756] RIP: 0010:remove_proc_entry+0x124/0x190 >>> [ 2908.144519] Code: c3 48 c7 c7 60 24 8b 82 e8 29 16 a5 00 eb d5 48 c7 c7 60 24 8b 82 e8 1b 16 a5 00 4c 89 e6 48 c7 c7 ec 4c 52 82 e8 50 fd db ff <0f> 0b eb b6 48 8b 04 24 83 a8 90 00 00 00 01 e9 78 ff ff ff 4c 89 >>> [ 2908.148138] RSP: 0018:ffffc900047bbdb0 EFLAGS: 00010282 >>> [ 2908.148945] RAX: 0000000000000000 RBX: ffff888036060580 RCX: 0000000000000000 >>> [ 2908.150139] RDX: ffff88807fd24e80 RSI: ffff88807fd165b8 RDI: 00000000ffffffff >>> [ 2908.151334] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 >>> [ 2908.152564] R10: 0000000000000000 R11: 0000000000000000 R12: ffffffffa00adb1b >>> [ 2908.153816] R13: 00007ffc8bda5d30 R14: 0000000000000000 R15: ffff88805e2873a8 >>> [ 2908.155007] FS: 00007f470bc27e40(0000) GS:ffff88807fd00000(0000) knlGS:0000000000000000 >>> [ 2908.156421] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 >>> [ 2908.157333] CR2: 0000562b07764c58 CR3: 000000005e8ea001 CR4: 00000000001606e0 >>> [ 2908.158529] Call Trace: >>> [ 2908.158796] destroy_use_gss_proxy_proc_entry+0xb7/0x150 [auth_rpcgss] >>> [ 2908.159966] gss_svc_shutdown_net+0x11/0x170 [auth_rpcgss] >>> [ 2908.160830] netns_evict+0x2f/0x40 >>> [ 2908.161266] nsfs_evict+0x27/0x40 >>> [ 2908.161685] evict+0xd0/0x1a0 >>> [ 2908.162035] __dentry_kill+0xdf/0x180 >>> [ 2908.162520] dentry_kill+0x50/0x1c0 >>> [ 2908.163005] ? dput+0x1c/0x2b0 >>> [ 2908.163369] dput+0x260/0x2b0 >>> [ 2908.163739] path_put+0x12/0x20 >>> [ 2908.164155] do_faccessat+0x17c/0x240 >>> [ 2908.164643] do_syscall_64+0x50/0x1c0 >>> [ 2908.165170] entry_SYSCALL_64_after_hwframe+0x49/0xbe >>> [ 2908.165959] RIP: 0033:0x7f47098e2157 >>> [ 2908.166445] Code: 77 01 c3 48 8b 15 69 dd 2c 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 b8 15 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 8b 15 39 dd 2c 00 f7 d8 64 89 02 b8 >>> [ 2908.169994] RSP: 002b:00007ffc8bda5d28 EFLAGS: 00000246 ORIG_RAX: 0000000000000015 >>> [ 2908.171315] RAX: ffffffffffffffda RBX: 0000562b0774d979 RCX: 00007f47098e2157 >>> [ 2908.172563] RDX: 00007ffc8bda5d3e RSI: 0000000000000000 RDI: 00007ffc8bda5d30 >>> [ 2908.173753] RBP: 00007ffc8bda5d70 R08: 0000000000000000 R09: 0000562b07d0b130 >>> [ 2908.174943] R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffc8bda5d30 >>> [ 2908.176163] R13: 0000562b07b34c80 R14: 0000562b07b35120 R15: 0000000000000000 >>> [ 2908.177395] irq event stamp: 4256 >>> [ 2908.177835] hardirqs last enabled at (4255): [] console_unlock+0x41e/0x590 >>> [ 2908.179378] hardirqs last disabled at (4256): [] trace_hardirqs_off_thunk+0x1a/0x1c >>> [ 2908.181031] softirqs last enabled at (4252): [] __do_softirq+0x2be/0x4aa >>> [ 2908.182458] softirqs last disabled at (4233): [] irq_exit+0x80/0x90 >>> [ 2908.183869] ---[ end trace d88132b63efc09d8 ]--- >>> [ 2908.184620] BUG: kernel NULL pointer dereference, address: 0000000000000030 >>> [ 2908.185829] #PF: supervisor read access in kernel mode >>> [ 2908.186924] #PF: error_code(0x0000) - not-present page >>> [ 2908.187887] PGD 0 P4D 0 >>> [ 2908.188318] Oops: 0000 [#1] PREEMPT SMP PTI >>> [ 2908.189254] CPU: 2 PID: 15032 Comm: (coredump) Tainted: G W 5.2.0-rc2-00441-gaef575f54640 #2257 >>> [ 2908.192506] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-2.fc30 04/01/2014 >>> [ 2908.195137] RIP: 0010:__lock_acquire+0x3d2/0x1d90 >>> [ 2908.196414] Code: db 48 8b 84 24 88 00 00 00 65 48 33 04 25 28 00 00 00 0f 85 be 10 00 00 48 8d 65 d8 44 89 d8 5b 41 5c 41 5d 41 5e 41 5f 5d c3 <48> 81 3f 60 0d 01 83 41 bb 00 00 00 00 45 0f 45 d8 83 fe 01 0f 87 >>> [ 2908.202720] RSP: 0018:ffffc900047bbc80 EFLAGS: 00010002 >>> [ 2908.204165] RAX: 0000000000000000 RBX: 0000000000000001 RCX: 0000000000000000 >>> [ 2908.206125] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000030 >>> [ 2908.208203] RBP: ffffc900047bbd40 R08: 0000000000000001 R09: 0000000000000000 >>> [ 2908.210219] R10: 0000000000000001 R11: 0000000000000001 R12: ffff88807ad91500 >>> [ 2908.211386] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000282 >>> [ 2908.212532] FS: 00007f470bc27e40(0000) GS:ffff88807fd00000(0000) knlGS:0000000000000000 >>> [ 2908.213647] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 >>> [ 2908.214400] CR2: 0000000000000030 CR3: 000000005e8ea001 CR4: 00000000001606e0 >>> [ 2908.215393] Call Trace: >>> [ 2908.215589] ? __lock_acquire+0x255/0x1d90 >>> [ 2908.216071] ? clear_gssp_clnt+0x1b/0x50 [auth_rpcgss] >>> [ 2908.216720] ? __mutex_lock+0x99/0x920 >>> [ 2908.217114] lock_acquire+0x95/0x1b0 >>> [ 2908.217484] ? cache_purge+0x1c/0x110 [sunrpc] >>> [ 2908.218000] _raw_spin_lock+0x2f/0x40 >>> [ 2908.218370] ? cache_purge+0x1c/0x110 [sunrpc] >>> [ 2908.218882] cache_purge+0x1c/0x110 [sunrpc] >>> [ 2908.219346] gss_svc_shutdown_net+0xb8/0x170 [auth_rpcgss] >>> [ 2908.220104] netns_evict+0x2f/0x40 >>> [ 2908.220439] nsfs_evict+0x27/0x40 >>> [ 2908.220786] evict+0xd0/0x1a0 >>> [ 2908.221050] __dentry_kill+0xdf/0x180 >>> [ 2908.221458] dentry_kill+0x50/0x1c0 >>> [ 2908.221842] ? dput+0x1c/0x2b0 >>> [ 2908.222126] dput+0x260/0x2b0 >>> [ 2908.222384] path_put+0x12/0x20 >>> [ 2908.222753] do_faccessat+0x17c/0x240 >>> [ 2908.223125] do_syscall_64+0x50/0x1c0 >>> [ 2908.223479] entry_SYSCALL_64_after_hwframe+0x49/0xbe >>> [ 2908.224152] RIP: 0033:0x7f47098e2157 >>> [ 2908.224566] Code: 77 01 c3 48 8b 15 69 dd 2c 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 b8 15 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 8b 15 39 dd 2c 00 f7 d8 64 89 02 b8 >>> [ 2908.228198] RSP: 002b:00007ffc8bda5d28 EFLAGS: 00000246 ORIG_RAX: 0000000000000015 >>> [ 2908.229496] RAX: ffffffffffffffda RBX: 0000562b0774d979 RCX: 00007f47098e2157 >>> [ 2908.230938] RDX: 00007ffc8bda5d3e RSI: 0000000000000000 RDI: 00007ffc8bda5d30 >>> [ 2908.232182] RBP: 00007ffc8bda5d70 R08: 0000000000000000 R09: 0000562b07d0b130 >>> [ 2908.233481] R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffc8bda5d30 >>> [ 2908.234750] R13: 0000562b07b34c80 R14: 0000562b07b35120 R15: 0000000000000000 >>> [ 2908.236068] Modules linked in: nfsv4 rpcsec_gss_krb5 nfsv3 nfs_acl nfs lockd grace auth_rpcgss sunrpc >>> [ 2908.237861] CR2: 0000000000000030 >>> [ 2908.238277] ---[ end trace d88132b63efc09d9 ]--- > . >