From 6e4eb9cb22fc8a893cb708ed42644de5ee7c3827 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (VMware)" Date: Thu, 5 Nov 2020 21:32:37 -0500 Subject: ftrace: Add ftrace_test_recursion_trylock() helper function To make it easier for ftrace callbacks to have recursion protection, provide a ftrace_test_recursion_trylock() and ftrace_test_recursion_unlock() helper that tests for recursion. Link: https://lkml.kernel.org/r/20201028115612.634927593@goodmis.org Link: https://lkml.kernel.org/r/20201106023546.378584067@goodmis.org Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/trace_functions.c | 12 +++++------- 1 file changed, 5 insertions(+), 7 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace_functions.c b/kernel/trace/trace_functions.c index 2c2126e1871d..943756c01190 100644 --- a/kernel/trace/trace_functions.c +++ b/kernel/trace/trace_functions.c @@ -141,22 +141,20 @@ function_trace_call(unsigned long ip, unsigned long parent_ip, if (unlikely(!tr->function_enabled)) return; + bit = ftrace_test_recursion_trylock(); + if (bit < 0) + return; + pc = preempt_count(); preempt_disable_notrace(); - bit = trace_test_and_set_recursion(TRACE_FTRACE_START, TRACE_FTRACE_MAX); - if (bit < 0) - goto out; - cpu = smp_processor_id(); data = per_cpu_ptr(tr->array_buffer.data, cpu); if (!atomic_read(&data->disabled)) { local_save_flags(flags); trace_function(tr, ip, parent_ip, flags, pc); } - trace_clear_recursion(bit); - - out: + ftrace_test_recursion_unlock(bit); preempt_enable_notrace(); } -- cgit v1.2.3