| Message ID | 20250106111143.2f90ff65@gandalf.local.home (mailing list archive) |
|---|---|
| State | Queued |
| Headers | show |
| Series | tracing: Fix using ret variable in tracing_set_tracer() | expand |
On Mon, 6 Jan 2025 11:11:43 -0500 Steven Rostedt <rostedt@goodmis.org> wrote: > From: Steven Rostedt <rostedt@goodmis.org> > > When the function tracing_set_tracer() switched over to using the guard() > infrastructure, it did not need to save the 'ret' variable and would just > return the value when an error arised, instead of setting ret and jumping > to an out label. > > When CONFIG_TRACER_SNAPSHOT is enabled, it had code that expected the > "ret" variable to be initialized to zero and had set 'ret' while holding > an arch_spin_lock() (not used by guard), and then upon releasing the lock > it would check 'ret' and exit if set. But because ret was only set when an > error occurred while holding the locks, 'ret' would be used uninitialized > if there was no error. The code in the CONFIG_TRACER_SNAPSHOT block should > be self contain. Make sure 'ret' is also set when no error occurred. > Looks good to me. Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Thanks, > Reported-by: kernel test robot <lkp@intel.com> > Reported-by: Dan Carpenter <dan.carpenter@linaro.org> > Closes: https://lore.kernel.org/r/202412271654.nJVBuwmF-lkp@intel.com/ > Fixes: d33b10c0c73ad ("tracing: Switch trace.c code over to use guard()") > Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> > --- > kernel/trace/trace.c | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-) > > diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c > index 0aaf442271e9..5aeb898054e7 100644 > --- a/kernel/trace/trace.c > +++ b/kernel/trace/trace.c > @@ -6104,8 +6104,7 @@ int tracing_set_tracer(struct trace_array *tr, const char *buf) > if (t->use_max_tr) { > local_irq_disable(); > arch_spin_lock(&tr->max_lock); > - if (tr->cond_snapshot) > - ret = -EBUSY; > + ret = tr->cond_snapshot ? -EBUSY : 0; > arch_spin_unlock(&tr->max_lock); > local_irq_enable(); > if (ret) > -- > 2.45.2 >
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 0aaf442271e9..5aeb898054e7 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -6104,8 +6104,7 @@ int tracing_set_tracer(struct trace_array *tr, const char *buf) if (t->use_max_tr) { local_irq_disable(); arch_spin_lock(&tr->max_lock); - if (tr->cond_snapshot) - ret = -EBUSY; + ret = tr->cond_snapshot ? -EBUSY : 0; arch_spin_unlock(&tr->max_lock); local_irq_enable(); if (ret)