From 06f90cf104fc21ee01e7ef1eb80e092173089b9f Mon Sep 17 00:00:00 2001 From: Zhiling Zou Date: Sat, 12 Sep 2026 21:56:09 +0800 Subject: [PATCH] SUNRPC: trace an accepted transport before publishing it svc_handle_xprt() publishes a newly accepted transport before tracing it. svc_add_new_temp_xprt() places the transport on sv_tempsocks and clears XPT_BUSY, so another nfsd thread can dequeue it at once. If the peer has already closed the connection, that thread runs svc_delete_xprt(), which drops the list reference, the only reference the new transport holds. trace_svc_xprt_accept() then reads the transport's addresses and network namespace from freed memory. Before publication the accepting thread owns the transport exclusively: XPT_BUSY is still set from svc_xprt_init() and the transport is on no list. Emit the tracepoint there. Fixes: 11bbb0f76e99 ("SUNRPC: Trace a few more generic svc_xprt events") Cc: stable@vger.kernel.org Reported-by: VEGA Assisted-by: LLM Signed-off-by: Zhiling Zou Link: https://patch.msgid.link/d15495bff2247e3f9d4f9ef36df8e246a3898380.1789220778.git.zhilinz@nebusec.ai [ cel: trace before publication instead of taking an extra reference ] Signed-off-by: Chuck Lever --- net/sunrpc/svc_xprt.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c index d5634dd6d6cc..5e210bc68422 100644 --- a/net/sunrpc/svc_xprt.c +++ b/net/sunrpc/svc_xprt.c @@ -861,8 +861,8 @@ static void svc_handle_xprt(struct svc_rqst *rqstp, struct svc_xprt *xprt) newxpt = xprt->xpt_ops->xpo_accept(xprt); if (newxpt) { newxpt->xpt_cred = get_cred(xprt->xpt_cred); - svc_add_new_temp_xprt(serv, newxpt); trace_svc_xprt_accept(newxpt, serv->sv_name); + svc_add_new_temp_xprt(serv, newxpt); } else { module_put(xprt->xpt_class->xcl_owner); }