From a32c7765e2796395aec49f699bd25c407155e9c5 Mon Sep 17 00:00:00 2001 From: Li Zefan Date: Fri, 26 Jun 2009 16:55:51 +0800 Subject: [PATCH] tracing: Fix stack tracer sysctl handling This made my machine completely frozen: # echo 1 > /proc/sys/kernel/stack_tracer_enabled # echo 2 > /proc/sys/kernel/stack_tracer_enabled The cause is register_ftrace_function() was called twice. Also fix ftrace_enabled sysctl, though seems nothing bad happened as I tested it. Signed-off-by: Li Zefan Cc: Steven Rostedt Cc: Frederic Weisbecker LKML-Reference: <4A448D17.9010305@cn.fujitsu.com> Signed-off-by: Ingo Molnar --- kernel/trace/ftrace.c | 4 ++-- kernel/trace/trace_stack.c | 4 ++-- 2 files changed, 4 insertions(+), 4 deletions(-) diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index f3716bf04df6..bce9e01a29c8 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -3160,10 +3160,10 @@ ftrace_enable_sysctl(struct ctl_table *table, int write, ret = proc_dointvec(table, write, file, buffer, lenp, ppos); - if (ret || !write || (last_ftrace_enabled == ftrace_enabled)) + if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled)) goto out; - last_ftrace_enabled = ftrace_enabled; + last_ftrace_enabled = !!ftrace_enabled; if (ftrace_enabled) { diff --git a/kernel/trace/trace_stack.c b/kernel/trace/trace_stack.c index 2d7aebd71dbd..e644af910124 100644 --- a/kernel/trace/trace_stack.c +++ b/kernel/trace/trace_stack.c @@ -326,10 +326,10 @@ stack_trace_sysctl(struct ctl_table *table, int write, ret = proc_dointvec(table, write, file, buffer, lenp, ppos); if (ret || !write || - (last_stack_tracer_enabled == stack_tracer_enabled)) + (last_stack_tracer_enabled == !!stack_tracer_enabled)) goto out; - last_stack_tracer_enabled = stack_tracer_enabled; + last_stack_tracer_enabled = !!stack_tracer_enabled; if (stack_tracer_enabled) register_ftrace_function(&trace_ops);