| Message ID | 1338039549-24498-1-git-send-email-anton.vorontsov@linaro.org |
|---|---|
| State | Superseded |
| Headers | show |
On Sat, 2012-05-26 at 06:39 -0700, Anton Vorontsov wrote: > If tracer->init() fails, current code will leave current_tracer pointing > to an unusable tracer, which at best makes 'current_tracer' report > inaccurate value. > > Fix the issue by pointing current_tracer to nop tracer, and only update > current_tracer with the new one after all the initialization succeeds. > Hmm, I'll look at this in more detail. This may be something I pull now. (for 3.6). -- Steve > Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org> > --- > kernel/trace/trace.c | 7 ++++--- > 1 file changed, 4 insertions(+), 3 deletions(-) > > diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c > index 68032c6..5cf7e67 100644 > --- a/kernel/trace/trace.c > +++ b/kernel/trace/trace.c > @@ -3172,10 +3172,10 @@ static int tracing_set_tracer(const char *buf) > } > destroy_trace_option_files(topts); > > - current_trace = t; > + current_trace = &nop_trace; > > - topts = create_trace_option_files(current_trace); > - if (current_trace->use_max_tr) { > + topts = create_trace_option_files(t); > + if (t->use_max_tr) { > int cpu; > /* we need to make per cpu buffer sizes equivalent */ > for_each_tracing_cpu(cpu) { > @@ -3195,6 +3195,7 @@ static int tracing_set_tracer(const char *buf) > goto out; > } > > + current_trace = t; > trace_branch_enable(tr); > out: > mutex_unlock(&trace_types_lock);
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 68032c6..5cf7e67 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -3172,10 +3172,10 @@ static int tracing_set_tracer(const char *buf) } destroy_trace_option_files(topts); - current_trace = t; + current_trace = &nop_trace; - topts = create_trace_option_files(current_trace); - if (current_trace->use_max_tr) { + topts = create_trace_option_files(t); + if (t->use_max_tr) { int cpu; /* we need to make per cpu buffer sizes equivalent */ for_each_tracing_cpu(cpu) { @@ -3195,6 +3195,7 @@ static int tracing_set_tracer(const char *buf) goto out; } + current_trace = t; trace_branch_enable(tr); out: mutex_unlock(&trace_types_lock);
If tracer->init() fails, current code will leave current_tracer pointing to an unusable tracer, which at best makes 'current_tracer' report inaccurate value. Fix the issue by pointing current_tracer to nop tracer, and only update current_tracer with the new one after all the initialization succeeds. Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org> --- kernel/trace/trace.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-)