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From: Peter Zijlstra <peterz@infradead.org>
To: David Laight <David.Laight@ACULAB.COM>
Cc: "Steven Rostedt" <rostedt@goodmis.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"Ingo Molnar" <mingo@kernel.org>,
	"Andrew Morton" <akpm@linux-foundation.org>,
	"Jiri Olsa" <jolsa@kernel.org>,
	"Naveen N . Rao" <naveen.n.rao@linux.ibm.com>,
	"Anil S Keshavamurthy" <anil.s.keshavamurthy@intel.com>,
	"David S . Miller" <davem@davemloft.net>,
	"Namhyung Kim" <namhyung@kernel.org>,
	"Toke Høiland-Jørgensen" <thoiland@redhat.com>,
	"Jean-Tsung Hsiao" <jhsiao@redhat.com>,
	"Jesper Dangaard Brouer" <brouer@redhat.com>,
	"stable@vger.kernel.org" <stable@vger.kernel.org>,
	"Arnaldo Carvalho de Melo" <acme@kernel.org>,
	"Arnaldo Carvalho de Melo" <acme@redhat.com>,
	"Masami Hiramatsu" <mhiramat@kernel.org>
Subject: Re: [for-linus][PATCH 2/5] tracing/uprobe: Fix double perf_event linking on multiprobe uprobe
Date: Tue, 21 Jan 2020 16:06:05 +0100	[thread overview]
Message-ID: <20200121150605.GT14879@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <bd3126fff15641098af2a4ac2164f3c4@AcuMS.aculab.com>

On Tue, Jan 21, 2020 at 02:59:35PM +0000, David Laight wrote:
> From: Peter Zijlstra
> > Sent: 21 January 2020 14:50
> > On Tue, Jan 21, 2020 at 09:38:49AM -0500, Steven Rostedt wrote:
> > > diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h
> > > index 4ee703728aec..03e4e180058d 100644
> > > --- a/kernel/trace/trace_probe.h
> > > +++ b/kernel/trace/trace_probe.h
> > > @@ -230,6 +230,7 @@ struct trace_probe_event {
> > >  	struct trace_event_call		call;
> > >  	struct list_head 		files;
> > >  	struct list_head		probes;
> > > +	char				data[0];
> > >  };
> > 
> > Note that this relies on pure 'luck'. If you stick anything <4 bytes in
> > between the list_head and the data member it'll come unstuck real fast.
> 
> Can you fix it by adding an unnamed struct as in:

The trivial fix is like I suggested in the other thread:

	struct trace_uprobe_filter filters[0];

The alternative that Masami-San suggested should also work.

  reply	other threads:[~2020-01-21 15:06 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-21 14:38 [for-linus][PATCH 0/5] tracing: Fixes for 5.5 Steven Rostedt
2020-01-21 14:38 ` [for-linus][PATCH 1/5] tracing: xen: Ordered comparison of function pointers Steven Rostedt
2020-01-21 14:38 ` [for-linus][PATCH 2/5] tracing/uprobe: Fix double perf_event linking on multiprobe uprobe Steven Rostedt
2020-01-21 14:50   ` Peter Zijlstra
2020-01-21 14:59     ` David Laight
2020-01-21 15:06       ` Peter Zijlstra [this message]
2020-01-22 22:12         ` Masami Hiramatsu
2020-01-21 14:38 ` [for-linus][PATCH 3/5] tracing: trigger: Replace unneeded RCU-list traversals Steven Rostedt
     [not found]   ` <20200122022623.20D812465A@mail.kernel.org>
2020-01-22  3:32     ` Masami Hiramatsu
2020-01-21 14:38 ` [for-linus][PATCH 4/5] tracing: Fix histogram code when expression has same var as value Steven Rostedt
2020-01-21 14:38 ` [for-linus][PATCH 5/5] tracing: Do not set trace clock if tracefs lockdown is in effect Steven Rostedt

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