Messages in this thread | | | Date | Fri, 11 Jul 2014 17:40:33 +0200 | Subject | Re: [PATCH] rcu: define tracepoint strings only if CONFIG_TRACING is set | From | Ard Biesheuvel <> |
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On 11 July 2014 17:30, Steven Rostedt <rostedt@goodmis.org> wrote: > On Fri, 11 Jul 2014 08:12:40 -0700 > "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> wrote: > >> On Fri, Jul 11, 2014 at 01:38:12PM +0200, Ard Biesheuvel wrote: >> > Commit f7f7bac9cb1c ("rcu: Have the RCU tracepoints use the tracepoint_string >> > infrastructure") unconditionally populates the __tracepoint_str input section, >> > but this section is not assigned an output section if CONFIG_TRACING is not set. >> > This results in the __tracepoint_str turning up in unexpected places, i.e., >> > after _edata. >> > >> > Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> >> > Cc: rostedt@goodmis.org >> > Cc: dipankar@in.ibm.com >> > Cc: paulmck@linux.vnet.ibm.com >> >> If you get a Reviewed-by from Steven Rostedt, I will be happy to queue >> this one. > > I'm fine with it, but it should add a comment. > > >> >> Thanx, Paul >> >> > --- >> > kernel/rcu/tree.c | 9 ++++++++- >> > 1 file changed, 8 insertions(+), 1 deletion(-) >> > >> > diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c >> > index f1ba77363fbb..ac1984149eb5 100644 >> > --- a/kernel/rcu/tree.c >> > +++ b/kernel/rcu/tree.c >> > @@ -79,9 +79,16 @@ static struct lock_class_key rcu_fqs_class[RCU_NUM_LVLS]; >> > * the tracing userspace tools to be able to decipher the string >> > * address to the matching string. >> > */ >> > +#ifdef CONFIG_TRACING > > /* > * When tracing is enabled, DEFINE_TPS() will export the string to > * userspace via the tracing debugfs directory. This allows userspace > * tools to read the binary tracepoints that reference the pointer > * to the string and not the string itself. > */ > > >> > +#define DEFINE_TPS(sname) \ >> > +static const char *tp_##sname##_varname __used __tracepoint_string = sname##_varname; >> > +#else >> > +#define DEFINE_TPS(sname) >> > +#endif > > Also, perhaps we should call it: > > DEFINE_RCU_TPS() > > Other than that, I'm fine with the patch. > > I'll review v2 ;-) >
Thanks gents, v2 coming up.
-- Ard.
>> > + >> > #define RCU_STATE_INITIALIZER(sname, sabbr, cr) \ >> > static char sname##_varname[] = #sname; \ >> > -static const char *tp_##sname##_varname __used __tracepoint_string = sname##_varname; \ >> > +DEFINE_TPS(sname) \ >> > struct rcu_state sname##_state = { \ >> > .level = { &sname##_state.node[0] }, \ >> > .call = cr, \ >> > -- >> > 1.8.3.2 >> > >
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