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authorSteven Rostedt (Red Hat) <rostedt@goodmis.org>2013-03-13 11:15:19 -0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-03-28 12:06:02 -0700
commit7bdb127976b88b761bdd0b2a2756b35681655ce1 (patch)
treedc35c5e029b8f07c849131d9f94a431156775824
parentcdeff82601556a61c22f6e27dfeefb9af823485a (diff)
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 <rostedt@goodmis.org> Cc: Paul McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--kernel/trace/ftrace.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 86fd4170d248..b2ca34aac77c 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -2709,8 +2709,8 @@ __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();