This is a note to let you know that I've just added the patch titled tracing: Fix free of probe entry by calling call_rcu_sched() to the 3.0-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: tracing-fix-free-of-probe-entry-by-calling-call_rcu_sched.patch and it can be found in the queue-3.0 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 740466bc89ad8bd5afcc8de220f715f62b21e365 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Red Hat)" <rostedt@xxxxxxxxxxx> Date: Wed, 13 Mar 2013 11:15:19 -0400 Subject: tracing: Fix free of probe entry by calling call_rcu_sched() From: "Steven Rostedt (Red Hat)" <rostedt@xxxxxxxxxxx> 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@xxxxxxxxxxx> Cc: Paul McKenney <paulmck@xxxxxxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- kernel/trace/ftrace.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -2709,8 +2709,8 @@ __unregister_ftrace_function_probe(char 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(); Patches currently in stable-queue which might be from rostedt@xxxxxxxxxxx are queue-3.0/tracing-fix-free-of-probe-entry-by-calling-call_rcu_sched.patch queue-3.0/tracing-fix-race-in-snapshot-swapping.patch -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html