From: "Steven Rostedt (Red Hat)" <[email protected]> Currently we do not know what buffer a module event was enabled in. On unload, it is safest to clear all buffer instances, not just the top level buffer.
Todo: Clear only the buffer that the event was used in. The infrastructure is there to do this, but it makes the code a bit more complex. Lets get the current code vetted before we add that. Signed-off-by: Steven Rostedt <[email protected]> --- kernel/trace/trace.c | 10 ++++++++-- kernel/trace/trace.h | 2 +- kernel/trace/trace_events.c | 10 +++++++--- 3 files changed, 16 insertions(+), 6 deletions(-) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index f743121..d852165 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -911,9 +911,15 @@ void tracing_reset_current(int cpu) tracing_reset(&global_trace, cpu); } -void tracing_reset_current_online_cpus(void) +void tracing_reset_all_online_cpus(void) { - tracing_reset_online_cpus(&global_trace); + struct trace_array *tr; + + mutex_lock(&trace_types_lock); + list_for_each_entry(tr, &ftrace_trace_arrays, list) { + tracing_reset_online_cpus(tr); + } + mutex_unlock(&trace_types_lock); } #define SAVED_CMDLINES 128 diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 50a9c81..e9486c74d 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -492,7 +492,7 @@ int tracing_is_enabled(void); void tracing_reset(struct trace_array *tr, int cpu); void tracing_reset_online_cpus(struct trace_array *tr); void tracing_reset_current(int cpu); -void tracing_reset_current_online_cpus(void); +void tracing_reset_all_online_cpus(void); int tracing_open_generic(struct inode *inode, struct file *filp); struct dentry *trace_create_file(const char *name, umode_t mode, diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index 9a7dc4b..a376ab5 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -1649,14 +1649,18 @@ static void trace_module_remove_events(struct module *mod) list_del(&file_ops->list); kfree(file_ops); } + up_write(&trace_event_mutex); /* * It is safest to reset the ring buffer if the module being unloaded - * registered any events that were used. + * registered any events that were used. The only worry is if + * a new module gets loaded, and takes on the same id as the events + * of this module. When printing out the buffer, traced events left + * over from this module may be passed to the new module events and + * unexpected results may occur. */ if (clear_trace) - tracing_reset_current_online_cpus(); - up_write(&trace_event_mutex); + tracing_reset_all_online_cpus(); } static int trace_module_notify(struct notifier_block *self, -- 1.7.10.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
