netdev - Re: [PATCH] SUNRPC: Convert from atomic_t to refcount_t on rpc_clnt->cl

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Message-ID: <1f12b3569565fa8590b45cc2fbe7c176ca7c5184.camel@hammerspace.com>
Date:   Sat, 17 Jul 2021 14:43:26 +0000
From:   Trond Myklebust <trondmy@...merspace.com>
To:     "tanxin.ctf@...il.com" <tanxin.ctf@...il.com>,
        "xiyuyang19@...an.edu.cn" <xiyuyang19@...an.edu.cn>,
        "davem@...emloft.net" <davem@...emloft.net>,
        "chuck.lever@...cle.com" <chuck.lever@...cle.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "kolga@...app.com" <kolga@...app.com>,
        "kuba@...nel.org" <kuba@...nel.org>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        "bfields@...ldses.org" <bfields@...ldses.org>,
        "anna.schumaker@...app.com" <anna.schumaker@...app.com>,
        "linux-nfs@...r.kernel.org" <linux-nfs@...r.kernel.org>
CC:     "yuanxzhang@...an.edu.cn" <yuanxzhang@...an.edu.cn>
Subject: Re: [PATCH] SUNRPC: Convert from atomic_t to refcount_t on
 rpc_clnt->cl_count

On Sat, 2021-07-17 at 18:18 +0800, Xiyu Yang wrote:
> refcount_t type and corresponding API can protect refcounters from
> accidental underflow and overflow and further use-after-free
> situations.
> 

Have you tested this patch? As far as I remember, the reason why we
never converted is that refcount_inc() gets upset and WARNs when you
bump a zero refcount, like we do very much on purpose in
rpc_free_auth(). Is that no longer the case?


-- 
Trond Myklebust
Linux NFS client maintainer, Hammerspace
trond.myklebust@...merspace.com