From 1e6cd6bdd31e809cf307be7239f0aacdf9f09544 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Red Hat)" Date: Wed, 13 Mar 2013 11:15:19 -0400 Subject: [PATCH] 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(). Cc: Paul McKenney Signed-off-by: Steven Rostedt Signed-off-by: Ben Hutchings --- kernel/trace/ftrace.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 6c880e882d313..0943d2a74491c 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -2725,8 +2725,8 @@ __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(); -- 2.47.3