Messages in this thread | | | Date | Wed, 06 Jan 2010 17:07:32 +0800 | From | Xiaotian Feng <> | Subject | Re: [PATCH] sunrpc: fix peername failed on closed listener |
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On 01/06/2010 07:01 AM, J. Bruce Fields wrote: > On Thu, Dec 31, 2009 at 10:52:36AM +0800, Xiaotian Feng wrote: >> There're some warnings of "nfsd: peername failed (err 107)!" >> socket error -107 means Transport endpoint is not connected. >> This warning message was outputed by svc_tcp_accept() [net/sunrpc/svcsock.c], >> when kernel_getpeername returns -107. This means socket might be CLOSED. >> >> And svc_tcp_accept was called by svc_recv() [net/sunrpc/svc_xprt.c] >> >> if (test_bit(XPT_LISTENER,&xprt->xpt_flags)) { >> <snip> >> newxpt = xprt->xpt_ops->xpo_accept(xprt); >> <snip> >> >> So this might happen when xprt->xpt_flags has both XPT_LISTENER and XPT_CLOSE. >> >> Let's take a look at commit b0401d72, this commit has moved the close >> processing after do recvfrom method, but this commit also introduces this >> warnings, if the xpt_flags has both XPT_LISTENER and XPT_CLOSED, we should >> close it, not accpet then close. > > The logic here seems unnecessarily complicated now, but as a minimal > fix, this seems fine. > > Is the *only* justification for this to silence this warning, or is > there some more serious problem I'm missing?
If a xprt->xpt_flags has XPT_CLOSE & XPT_LISTENER, kernel will accept it first, and svc_xprt_received(xptr) no mater xpo_accept is suceed or failed, then svc_delete_xprt(xprt).
I'm not sure what will happened between the svc_xprt_received and svc_delete_xprt, there isn't any lock to protect it.
> > --b. > >> >> Signed-off-by: Xiaotian Feng<dfeng@redhat.com> >> Cc: J. Bruce Fields<bfields@fieldses.org> >> Cc: Neil Brown<neilb@suse.de> >> Cc: Trond Myklebust<Trond.Myklebust@netapp.com> >> Cc: David S. Miller<davem@davemloft.net> >> --- >> diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c >> index 1c924ee..187f0f4 100644 >> --- a/net/sunrpc/svc_xprt.c >> +++ b/net/sunrpc/svc_xprt.c >> @@ -699,7 +699,8 @@ int svc_recv(struct svc_rqst *rqstp, long timeout) >> spin_unlock_bh(&pool->sp_lock); >> >> len = 0; >> - if (test_bit(XPT_LISTENER,&xprt->xpt_flags)) { >> + if (test_bit(XPT_LISTENER,&xprt->xpt_flags)&& >> + !test_bit(XPT_CLOSE,&xprt->xpt_flags)) { >> struct svc_xprt *newxpt; >> newxpt = xprt->xpt_ops->xpo_accept(xprt); >> if (newxpt) { >
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