From: Steven Rostedt (Red Hat) Date: Wed, 13 Mar 2013 15:15:19 +0000 (-0400) Subject: tracing: Fix free of probe entry by calling call_rcu_sched() X-Git-Tag: v3.8.5~60 X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=f3654cba3e270f698589fafa047091df3cad3c1c;p=karo-tx-linux.git tracing: Fix free of probe entry by calling call_rcu_sched() commit 740466bc89ad8bd5afcc8de220f715f62b21e365 upstream. Because function tracing is very invasive, and can even trace calls to rcu_read_lock(), RCU access in function tracing is done with preempt_disable_notrace(). This requires a synchronize_sched() for updates and not a synchronize_rcu(). Function probes (traceon, traceoff, etc) must be freed after a synchronize_sched() after its entry has been removed from the hash. But call_rcu() is used. Fix this by using call_rcu_sched(). Also fix the usage to use hlist_del_rcu() instead of hlist_del(). Signed-off-by: Steven Rostedt Cc: Paul McKenney Signed-off-by: Greg Kroah-Hartman --- diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 43defd141805..b27052cc3ee8 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -3082,8 +3082,8 @@ __unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops, continue; } - hlist_del(&entry->node); - call_rcu(&entry->rcu, ftrace_free_entry_rcu); + hlist_del_rcu(&entry->node); + call_rcu_sched(&entry->rcu, ftrace_free_entry_rcu); } } __disable_ftrace_function_probe();