From: "wanghai (M)" <wanghai38@huawei.com>
To: "J. Bruce Fields" <bfields@fieldses.org>,
Wenbin Zeng <wenbin.zeng@gmail.com>
Cc: <davem@davemloft.net>, <viro@zeniv.linux.org.uk>,
<jlayton@kernel.org>, <trond.myklebust@hammerspace.com>,
<anna.schumaker@netapp.com>, <wenbinzeng@tencent.com>,
<dsahern@gmail.com>, <nicolas.dichtel@6wind.com>,
<willy@infradead.org>, <edumazet@google.com>,
<jakub.kicinski@netronome.com>, <tyhicks@canonical.com>,
<chuck.lever@oracle.com>, <neilb@suse.com>,
<linux-fsdevel@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
<netdev@vger.kernel.org>, <linux-nfs@vger.kernel.org>
Subject: Re: Re: [PATCH v3 0/3] auth_gss: netns refcount leaks when use-gss-proxy==1
Date: Sat, 28 Aug 2021 19:26:30 +0800 [thread overview]
Message-ID: <9cfbd851-81ce-e272-8693-d3430c381c7a@huawei.com> (raw)
In-Reply-To: <20190801195346.GA21527@fieldses.org>
在 2019/8/2 3:53, J. Bruce Fields 写道:
> I lost track, what happened to these patches?
>
> --b.
>
> On Wed, Jun 12, 2019 at 08:09:27PM +0800, Wenbin Zeng wrote:
>> This patch series fixes an auth_gss bug that results in netns refcount
>> leaks when use-gss-proxy is set to 1.
>>
>> The problem was found in privileged docker containers with gssproxy service
>> enabled and /proc/net/rpc/use-gss-proxy set to 1, the corresponding
>> struct net->count ends up at 2 after container gets killed, the consequence
>> is that the struct net cannot be freed.
>>
>> It turns out that write_gssp() called gssp_rpc_create() to create a rpc
>> client, this increases net->count by 2; rpcsec_gss_exit_net() is supposed
>> to decrease net->count but it never gets called because its call-path is:
>> net->count==0 -> cleanup_net -> ops_exit_list -> rpcsec_gss_exit_net
>> Before rpcsec_gss_exit_net() gets called, net->count cannot reach 0, this
>> is a deadlock situation.
>>
>> To fix the problem, we must break the deadlock, rpcsec_gss_exit_net()
>> should move out of the put() path and find another chance to get called,
>> I think nsfs_evict() is a good place to go, when netns inode gets evicted
>> we call rpcsec_gss_exit_net() to free the rpc client, this requires a new
>> callback i.e. evict to be added in struct proc_ns_operations, and add
>> netns_evict() as one of netns_operations as well.
>>
>> v1->v2:
>> * in nsfs_evict(), move ->evict() in front of ->put()
>> v2->v3:
>> * rpcsec_gss_evict_net() directly call gss_svc_shutdown_net() regardless
>> if gssp_clnt is null, this is exactly same to what rpcsec_gss_exit_net()
>> previously did
>>
>> Wenbin Zeng (3):
>> nsfs: add evict callback into struct proc_ns_operations
>> netns: add netns_evict into netns_operations
>> auth_gss: fix deadlock that blocks rpcsec_gss_exit_net when
>> use-gss-proxy==1
>>
>> fs/nsfs.c | 2 ++
>> include/linux/proc_ns.h | 1 +
>> include/net/net_namespace.h | 1 +
>> net/core/net_namespace.c | 12 ++++++++++++
>> net/sunrpc/auth_gss/auth_gss.c | 4 ++--
>> 5 files changed, 18 insertions(+), 2 deletions(-)
>>
>> --
>> 1.8.3.1
These patchsets don't seem to merge into the mainline, are there any
other patches that fix this bug?
prev parent reply other threads:[~2021-08-28 11:26 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-01 6:42 [PATCH 0/3] auth_gss: netns refcount leaks when use-gss-proxy==1 Wenbin Zeng
2019-05-01 6:42 ` [PATCH 1/3] nsfs: add evict callback into struct proc_ns_operations Wenbin Zeng
2019-05-02 3:04 ` Al Viro
2019-05-04 16:08 ` Wenbin Zeng
2019-05-01 6:42 ` [PATCH 2/3] netns: add netns_evict into netns_operations Wenbin Zeng
2019-05-04 4:10 ` David Miller
2019-05-01 6:42 ` [PATCH 3/3] auth_gss: fix deadlock that blocks rpcsec_gss_exit_net when use-gss-proxy==1 Wenbin Zeng
2019-05-09 20:52 ` [PATCH 0/3] auth_gss: netns refcount leaks " J. Bruce Fields
2019-05-10 5:09 ` Wenbin Zeng
2019-05-10 6:36 ` [PATCH v2 " Wenbin Zeng
2019-05-10 6:36 ` [PATCH v2 1/3] nsfs: add evict callback into struct proc_ns_operations Wenbin Zeng
2019-05-10 6:36 ` [PATCH v2 2/3] netns: add netns_evict into netns_operations Wenbin Zeng
2019-05-10 22:13 ` David Miller
2019-05-10 6:36 ` [PATCH v2 3/3] auth_gss: fix deadlock that blocks rpcsec_gss_exit_net when use-gss-proxy==1 Wenbin Zeng
2019-05-15 1:03 ` [PATCH v2 0/3] auth_gss: netns refcount leaks " J. Bruce Fields
2019-06-12 8:37 ` Wenbin Zeng
2019-06-12 15:52 ` J. Bruce Fields
2021-09-07 14:48 ` wanghai (M)
2021-09-08 20:51 ` J. Bruce Fields
2021-09-09 2:52 ` wanghai (M)
2021-09-09 19:52 ` J. Bruce Fields
2019-06-12 12:09 ` [PATCH v3 " Wenbin Zeng
2019-06-12 12:09 ` [PATCH v3 1/3] nsfs: add evict callback into struct proc_ns_operations Wenbin Zeng
2019-06-12 12:09 ` [PATCH v3 2/3] netns: add netns_evict into netns_operations Wenbin Zeng
2019-06-12 12:09 ` [PATCH v3 3/3] auth_gss: fix deadlock that blocks rpcsec_gss_exit_net when use-gss-proxy==1 Wenbin Zeng
2019-08-01 19:53 ` [PATCH v3 0/3] auth_gss: netns refcount leaks " J. Bruce Fields
2021-08-28 11:26 ` wanghai (M) [this message]
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