Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932848AbbHZNxB (ORCPT ); Wed, 26 Aug 2015 09:53:01 -0400 Received: from mx1.redhat.com ([209.132.183.28]:39333 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932450AbbHZNxA (ORCPT ); Wed, 26 Aug 2015 09:53:00 -0400 Date: Wed, 26 Aug 2015 19:22:56 +0530 From: Pratyush Anand To: Jeff Layton Cc: bfields@fieldses.org, Steven Rostedt , Ingo Molnar , "J. Bruce Fields" , Jeff Layton , open list , Masami Hiramatsu , Trond Myklebust Subject: Re: [PATCH V2] net: sunrpc: fix tracepoint Warning: unknown op '->' Message-ID: <20150826135256.GI13340@dhcppc13.redhat.com> References: <9a330bdb057e1a0db14c6e475b94cab2a1e1e134.1440592574.git.panand@redhat.com> <20150826091302.61c53f77@tlielax.poochiereds.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150826091302.61c53f77@tlielax.poochiereds.net> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3918 Lines: 112 On 26/08/2015:09:13:02 AM, Jeff Layton wrote: > On Wed, 26 Aug 2015 18:10:44 +0530 > Pratyush Anand wrote: > > > `perf stat -e sunrpc:svc_xprt_do_enqueue true` results in > > > > Warning: unknown op '->' > > Warning: [sunrpc:svc_xprt_do_enqueue] unknown op '->' > > > > Similar warning for svc_handle_xprt as well. > > > > Actually TP_printk() should never dereference an address saved in the ring > > buffer that points somewhere in the kernel. There's no guarantee that that > > object still exists (with the exception of static strings). > > > > Therefore change all the arguments for TP_printk(), so that it references > > values existing in the ring buffer only. > > > > While doing that, also fix another possible bug when argument xprt could be > > NULL and TP_fast_assign() tries to access it's elements. > > > > Signed-off-by: Pratyush Anand > > Acked-by: Steven Rostedt > > --- > > Changes since V1: > > - struct sockaddr memcopied to ring buffer so that its internal element can > > be accessed while printing %pIS. > > > > include/trace/events/sunrpc.h | 23 ++++++++++++++++------- > > 1 file changed, 16 insertions(+), 7 deletions(-) > > > > diff --git a/include/trace/events/sunrpc.h b/include/trace/events/sunrpc.h > > index fd1a02cb3c82..75a16fcc0795 100644 > > --- a/include/trace/events/sunrpc.h > > +++ b/include/trace/events/sunrpc.h > > @@ -529,18 +529,23 @@ TRACE_EVENT(svc_xprt_do_enqueue, > > > > TP_STRUCT__entry( > > __field(struct svc_xprt *, xprt) > > + __field_struct(struct sockaddr_storage, ss) > > __field(struct svc_rqst *, rqst) > > nit: I think you should be able to avoid storing "rqst" now. Yes. > > > + __field(int, pid) > > + __field(unsigned long, flags) > > ), > > > > TP_fast_assign( > > - __entry->xprt = xprt; > > + __entry->xprt = xprt, > > Shouldn't that line end with ';'? > I think, both should be OK.. I just copied this hunk from svc_xprt_dequeue. > > + xprt ? memcpy(&__entry->ss, &xprt->xpt_remote, sizeof(__entry->ss)) : memset(&__entry->ss, 0, sizeof(__entry->ss)); > > __entry->rqst = rqst; > > + __entry->pid = rqst? rqst->rq_task->pid : 0; > > + __entry->flags = xprt ? xprt->xpt_flags : 0; > > ), > > > > TP_printk("xprt=0x%p addr=%pIScp pid=%d flags=%s", __entry->xprt, > > - (struct sockaddr *)&__entry->xprt->xpt_remote, > > - __entry->rqst ? __entry->rqst->rq_task->pid : 0, > > - show_svc_xprt_flags(__entry->xprt->xpt_flags)) > > + (struct sockaddr *)&__entry->ss, > > + __entry->pid, show_svc_xprt_flags(__entry->flags)) > > ); > > > > TRACE_EVENT(svc_xprt_dequeue, > > @@ -589,16 +594,20 @@ TRACE_EVENT(svc_handle_xprt, > > TP_STRUCT__entry( > > __field(struct svc_xprt *, xprt) > > __field(int, len) > > + __field_struct(struct sockaddr_storage, ss) > > + __field(unsigned long, flags) > > ), > > > > TP_fast_assign( > > - __entry->xprt = xprt; > > + __entry->xprt = xprt, > > + xprt ? memcpy(&__entry->ss, &xprt->xpt_remote, sizeof(__entry->ss)) : memset(&__entry->ss, 0, sizeof(__entry->ss)); > > __entry->len = len; > > + __entry->flags = xprt ? xprt->xpt_flags : 0; > > ), > > > > TP_printk("xprt=0x%p addr=%pIScp len=%d flags=%s", __entry->xprt, > > - (struct sockaddr *)&__entry->xprt->xpt_remote, __entry->len, > > - show_svc_xprt_flags(__entry->xprt->xpt_flags)) > > + (struct sockaddr *)&__entry->ss, > > + __entry->len, show_svc_xprt_flags(__entry->flags)) > > ); > > #endif /* _TRACE_SUNRPC_H */ > > > > Looks good otherwise. Thanks for fixing this! > > Reviewed-by: Jeff Layton Thanks :-) ~Pratyush -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/