Date: Tue, 19 Dec 2017 14:00:11 +1100 From: "Tobin C. Harding" <me@...in.cc> To: Steven Rostedt <rostedt@...dmis.org> Cc: kernel-hardening@...ts.openwall.com, Tycho Andersen <tycho@...ho.ws>, Linus Torvalds <torvalds@...ux-foundation.org>, Kees Cook <keescook@...omium.org>, Andrew Morton <akpm@...ux-foundation.org>, Daniel Borkmann <daniel@...earbox.net>, Masahiro Yamada <yamada.masahiro@...ionext.com>, Alexei Starovoitov <ast@...nel.org>, linux-kernel@...r.kernel.org, Network Development <netdev@...r.kernel.org> Subject: Re: [PATCH 3/3] trace: print address if symbol not found On Mon, Dec 18, 2017 at 06:51:43PM -0500, Steven Rostedt wrote: > On Tue, 19 Dec 2017 08:16:14 +1100 > "Tobin C. Harding" <me@...in.cc> wrote: > > > > > #endif /* _LINUX_KERNEL_TRACE_H */ > > > > diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c > > > > index 1e1558c99d56..3e28522a76f4 100644 > > > > --- a/kernel/trace/trace_events_hist.c > > > > +++ b/kernel/trace/trace_events_hist.c > > > > @@ -982,7 +982,7 @@ static void hist_trigger_stacktrace_print(struct seq_file *m, > > > > return; > > > > > > > > seq_printf(m, "%*c", 1 + spaces, ' '); > > > > - sprint_symbol(str, stacktrace_entries[i]); > > > > + trace_sprint_symbol_addr(str, stacktrace_entries[i]); > > > > > > > > If you have the time to give me some brief pointers on how I should go > > about testing this I'd love to test it before the next version. I know > > very little about ftrace. > > For hitting the histogram stacktrace trigger (this code path), make > sure you have CONFIG_HIST_TRIGGERS enabled. And then do: > > # cd /sys/kernel/debug/tracing > # echo 'hist:keys=common_pid.execname,stacktrace:vals=prev_state' > \ > events/sched/sched_switch/trigger > # cat events/sched/sched_switch/hist > > For the "sym" part, you can do (from the same directory): > > # echo 'hist:keys=call_site.sym:vals=bytes_req' > \ > events/kmem/kmalloc/trigger > # cat events/kmem/kmalloc/hist > > > And for sym-offset: > > # echo 'hist:keys=call_site.sym-offset:vals=bytes_req' > \ > events/kmem/kmalloc/trigger > # cat events/kmem/kmalloc/hist I ran through these as outlined here for the new version (v4). This hits the modified code but doesn't test symbol look up failure. I also configured kernel with 'Perform a startup test on ftrace' for good luck. Are you happy with this level of testing? thanks, Tobin.
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