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

Sorry, I'm not sure why you need to bump a zero refcount in a normal situation. But maybe we can use refcount_inc_not_zero() API in rpc_free_auth() instead?

-----Original Messages-----
From: "Trond Myklebust" <redacted>
Sent Time: 2021-07-17 22:43:26 (Saturday)
To: "tanxin.ctf@gmail.com" <redacted>, "xiyuyang19@fudan.edu.cn" <redacted>, "davem@davemloft.net" <davem@davemloft.net>, "chuck.lever@oracle.com" <redacted>, "linux-kernel@vger.kernel.org" <redacted>, "kolga@netapp.com" <redacted>, "kuba@kernel.org" <kuba@kernel.org>, "netdev@vger.kernel.org" <redacted>, "bfields@fieldses.org" <redacted>, "anna.schumaker@netapp.com" <redacted>, "linux-nfs@vger.kernel.org" <redacted>
Cc: "yuanxzhang@fudan.edu.cn" <redacted>
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:

quoted

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@hammerspace.com