diff options
Diffstat (limited to 'include/linux/ftrace.h')
| -rw-r--r-- | include/linux/ftrace.h | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index f4233b195dab..ef1607ed7044 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -105,11 +105,23 @@ enum { FTRACE_OPS_FL_INITIALIZED = 1 << 8, }; +/* + * Note, ftrace_ops can be referenced outside of RCU protection. + * (Although, for perf, the control ops prevent that). If ftrace_ops is + * allocated and not part of kernel core data, the unregistering of it will + * perform a scheduling on all CPUs to make sure that there are no more users. + * Depending on the load of the system that may take a bit of time. + * + * Any private data added must also take care not to be freed and if private + * data is added to a ftrace_ops that is in core code, the user of the + * ftrace_ops must perform a schedule_on_each_cpu() before freeing it. + */ struct ftrace_ops { ftrace_func_t func; struct ftrace_ops *next; unsigned long flags; int __percpu *disabled; + void *private; #ifdef CONFIG_DYNAMIC_FTRACE struct ftrace_hash *notrace_hash; struct ftrace_hash *filter_hash; |