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tracing: Fix stack tracer sysctl handling

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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 <lizf@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <4A448D17.9010305@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Li Zefan 2009-06-26 16:55:51 +08:00 committed by Ingo Molnar
parent 0296e4254f
commit a32c7765e2
2 changed files with 4 additions and 4 deletions
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4
kernel/trace/ftrace.c
View file

@ -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) {

4
kernel/trace/trace_stack.c
View file

@ -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);