Messages in this thread Patch in this message | | | Date | Fri, 30 Aug 2013 09:02:09 -0400 | From | Steven Rostedt <> | Subject | [RFC][PATCH 4/8] ftrace: Add test for ops against unsafe RCU functions in callback |
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From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
When more than one ftrace_ops is registered, the list function is is used to call all registered functions. It uses the filter and notrace hashes from the ftrace_ops to determine if the corresponding callback should be called or not.
Currently, it does not take into account for RCU unsafe functions. If multiple functions are registered, and an RCU safe callback is used on a RCU unsafe function, and the RCU unsafe callback says to trace all functions, it will end up tracing this RCU unsafe function and still suffer the problems when using RCU when RCU tracing is off.
Add a test to the multiple ops list function to test if the ops in question can use an RCU unsafe function or not, and if the function being traced happens to be an RCU unsafe function.
Cc: Jiri Olsa <jolsa@redhat.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> --- kernel/trace/ftrace.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 3761663..c7ef936 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -1471,7 +1471,9 @@ ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs) if ((ftrace_hash_empty(filter_hash) || ftrace_lookup_ip(filter_hash, ip)) && (ftrace_hash_empty(notrace_hash) || - !ftrace_lookup_ip(notrace_hash, ip))) + !ftrace_lookup_ip(notrace_hash, ip)) && + (ops->flags & FTRACE_OPS_FL_RCU_SAFE || + !ftrace_lookup_ip(ftrace_unsafe_rcu, ip))) ret = 1; else ret = 0; -- 1.7.10.4
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